Centralize NAX condition (#2811)

Co-authored-by: Awni Hannun <awni@apple.com>
Co-authored-by: Angelos Katharopoulos <katharas@gmail.com>
Co-authored-by: Angelos Katharopoulos <a_katharopoulos@apple.com>

.circleci/config.yml

@@ -1,579 +0,0 @@
-version: 2.1
-
-orbs:
-  apple: ml-explore/pr-approval@0.1.0
-
-parameters:
-  nightly_build:
-    type: boolean
-    default: false
-  test_release:
-    type: boolean
-    default: false
-
-jobs:
-  build_documentation:
-    parameters:
-      upload-docs:
-        type: boolean
-        default: false
-    macos:
-      xcode: "26.0.0"
-    resource_class: m4pro.medium
-    steps:
-      - checkout
-      - run:
-          name: Install
-          command: |
-            xcodebuild -downloadComponent MetalToolchain
-            brew install python@3.10
-            brew install doxygen
-            python3.10 -m venv env
-            source env/bin/activate
-            pip install --upgrade pip
-            pip install --upgrade cmake
-            pip install -r docs/requirements.txt
-            pip install . -v
-      - when:
-          condition:
-            not: << parameters.upload-docs >>
-          steps:
-            - run:
-               name: Build documentation
-               command: |
-                 source env/bin/activate
-                 cd docs && doxygen && make html O=-W
-      - when:
-          condition: << parameters.upload-docs >>
-          steps:
-            - add_ssh_keys:
-                fingerprints:
-                  - "SHA256:OhcVVMovbT0pkgMeiVRyxMnjV9R2t+hKBsNcuxq9h+0"
-            - run:
-               name: Upload documentation
-               command: |
-                 source env/bin/activate
-                 git config user.email "mlx@group.apple.com"
-                 git config user.name "CircleCI Docs"
-                 git checkout gh-pages
-                 git rebase main
-                 cd docs
-                 git rm -rf build/html
-                 doxygen && make html O=-W
-                 git add -f build/html
-                 git commit -m "rebase"
-                 git push -f origin gh-pages
-
-  linux_build_and_test:
-    machine:
-      image: ubuntu-2204:current
-      resource_class: large
-    steps:
-      - checkout
-      - run:
-          name: Run style checks
-          command: |
-            pip install pre-commit
-            pre-commit run --all
-            if ! git diff --quiet; then echo 'Style checks failed, please install pre-commit and run pre-commit run --all and push the change'; exit 1; fi
-      - run:
-          name: Install dependencies
-          command: |
-            export DEBIAN_FRONTEND=noninteractive
-            export NEEDRESTART_MODE=a
-            sudo apt-get update
-            sudo apt-get install -y libblas-dev liblapack-dev liblapacke-dev
-            sudo apt-get install openmpi-bin openmpi-common libopenmpi-dev
-            curl -LsSf https://astral.sh/uv/install.sh | sh
-      - run:
-          name: Install Python package
-          command: |
-            uv venv
-            uv pip install cmake
-            DEBUG=1 CMAKE_ARGS="-DCMAKE_COMPILE_WARNING_AS_ERROR=ON" \
-              uv pip install -e ".[dev]" -v
-      - run:
-          name: Generate package stubs
-          command: |
-            uv pip install typing_extensions
-            uv run --no-project setup.py generate_stubs
-      - run:
-          name: Run Python tests
-          command: |
-            source .venv/bin/activate
-            python -m unittest discover python/tests -v
-            mpirun --bind-to none -host localhost:8 -np 8 python python/tests/mpi_test_distributed.py
-            mlx.launch --verbose -n 8 python/tests/ring_test_distributed.py -v 2> >(tee -a stderr.log >&2)
-            if $(grep "\[WARN\]" stderr.log); then echo "Distributed ring test failed"; exit 1; fi
-      - run:
-          name: Build CPP only
-          command: |
-            source .venv/bin/activate
-            mkdir -p build && cd build
-            cmake .. -DMLX_BUILD_METAL=OFF -DCMAKE_BUILD_TYPE=DEBUG
-            make -j `nproc`
-      - run:
-          name: Run CPP tests
-          command: ./build/tests/tests
-
-  mac_build_and_test:
-    parameters:
-      xcode_version:
-        type: string
-        default: "26.0.0"
-      macosx_deployment_target:
-        type: string
-        default: ""
-    macos:
-      xcode: << parameters.xcode_version >>
-    environment:
-      MACOSX_DEPLOYMENT_TARGET: << parameters.macosx_deployment_target >>
-    resource_class: m4pro.medium
-    steps:
-      - checkout
-      - run:
-          name: Install dependencies
-          command: |
-            xcodebuild -downloadComponent MetalToolchain
-            HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1 \
-              brew install openmpi uv
-      - run:
-          name: Install Python package
-          command: |
-            uv venv --python 3.10
-            uv pip install \
-              nanobind==2.4.0 \
-              cmake \
-              numpy \
-              torch \
-              tensorflow \
-              unittest-xml-reporting
-            DEBUG=1 CMAKE_ARGS="-DCMAKE_COMPILE_WARNING_AS_ERROR=ON" \
-              uv pip install -e . -v
-      - run:
-          name: Generate package stubs
-          command: |
-            uv pip install typing_extensions
-            uv run --no-project setup.py generate_stubs
-      - run:
-          name: Run Python tests
-          command: |
-            source .venv/bin/activate
-            LOW_MEMORY=1 DEVICE=cpu python -m xmlrunner discover -v python/tests -o test-results/cpu
-            LOW_MEMORY=1 DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 python -m xmlrunner discover -v python/tests -o test-results/gpu
-            mpirun --bind-to none -host localhost:8 -np 8 -x DYLD_LIBRARY_PATH=/opt/homebrew/lib/ python python/tests/mpi_test_distributed.py
-            mlx.launch --verbose -n 8 python/tests/ring_test_distributed.py -v 2> >(tee -a stderr.log >&2)
-            if $(grep "\[WARN\]" stderr.log); then echo "Distributed ring test failed"; exit 1; fi
-      - run:
-          name: Build example extension
-          command: |
-            source .venv/bin/activate
-            cd examples/extensions
-            uv pip install -r requirements.txt
-            uv run --no-project setup.py build_ext --inplace
-            uv run --no-project python test.py
-      - store_test_results:
-          path: test-results
-      - run:
-          name: Build CPP only
-          command: |
-            source .venv/bin/activate
-            mkdir -p build && cd build && cmake .. && make -j `sysctl -n hw.ncpu`
-      - run:
-          name: Run CPP tests
-          command: |
-            DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 ./build/tests/tests
-      - run:
-          name: Build small binary
-          command: |
-            source .venv/bin/activate
-            cd build/
-            cmake .. -DCMAKE_BUILD_TYPE=MinSizeRel \
-              -DBUILD_SHARED_LIBS=ON \
-              -DMLX_BUILD_CPU=OFF \
-              -DMLX_BUILD_SAFETENSORS=OFF \
-              -DMLX_BUILD_GGUF=OFF \
-              -DMLX_METAL_JIT=ON
-            make -j `sysctl -n hw.ncpu`
-      - run:
-          name: Run Python tests with JIT
-          command: |
-            CMAKE_ARGS="-DMLX_METAL_JIT=ON" \
-              uv pip install -e . -v
-            LOW_MEMORY=1 DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 \
-              METAL_DEBUG_ERROR_MODE=0 \
-              uv run --no-project python -m xmlrunner discover \
-                -v python/tests \
-                -o test-results/gpu_jit
-
-  cuda_build_and_test:
-    parameters:
-      image_date:
-        type: string
-        default: "2023.11.1"
-    machine:
-      image: "linux-cuda-12:<< parameters.image_date >>"
-      resource_class: gpu.nvidia.small.gen2
-    steps:
-      - checkout
-      - restore_cache:
-          keys:
-            - cuda-<< parameters.image_date >>-{{ arch }}-
-      - run:
-          name: Install dependencies
-          command: |
-            sudo apt-get update
-            sudo apt-get install libcudnn9-dev-cuda-12
-            sudo apt-get install libblas-dev liblapack-dev liblapacke-dev
-            sudo apt-get install libnccl2 libnccl-dev
-            curl -sL https://github.com/ccache/ccache/releases/download/v4.11.3/ccache-4.11.3-linux-x86_64.tar.xz | tar xJf -
-            sudo mv ccache-4.11.3-linux-x86_64/ccache /usr/bin/ccache
-            rm -rf ccache-4.11.3-linux-x86_64
-            curl -LsSf https://astral.sh/uv/install.sh | sh
-      - run:
-          name: Set CCache size
-          command: ccache --max-size 1G
-      - run:
-          name: Install Python package
-          command: |
-            uv venv
-            uv pip install cmake
-            DEBUG=1 CMAKE_ARGS="-DMLX_BUILD_CUDA=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DCMAKE_CUDA_COMPILER=`which nvcc`" \
-              uv pip install -e ".[dev]" -v
-      - run:
-          name: Run Python tests
-          command: |
-            source .venv/bin/activate
-            LOW_MEMORY=1 DEVICE=cpu python -m unittest discover python/tests -v
-            LOW_MEMORY=1 DEVICE=gpu python -m tests discover python/tests -v
-      - run:
-          name: Build CPP only
-          command: |
-            source .venv/bin/activate
-            cmake . -B build \
-              -DMLX_BUILD_CUDA=ON \
-              -DCMAKE_CUDA_COMPILER=`which nvcc` \
-              -DCMAKE_BUILD_TYPE=DEBUG
-            cmake --build build -j `nproc`
-      - run:
-          name: Run CPP tests
-          command: ./build/tests/tests -sfe="*fft_tests.cpp,*linalg_tests.cpp"
-      - run:
-          name: CCache report
-          command: |
-            ccache --show-stats
-            ccache --zero-stats
-            ccache --cleanup
-      - save_cache:
-          key: cuda-<< parameters.image_date >>-{{ arch }}-{{ epoch }}
-          paths:
-            - /home/circleci/.cache/ccache
-
-  build_release:
-    parameters:
-      python_version:
-        type: string
-        default: "3.10"
-      xcode_version:
-        type: string
-        default: "26.0.0"
-      build_env:
-        type: string
-        default: ""
-      macosx_deployment_target:
-        type: string
-        default: ""
-    macos:
-      xcode: << parameters.xcode_version >>
-    resource_class: m4pro.medium
-    environment:
-      MACOSX_DEPLOYMENT_TARGET: << parameters.macosx_deployment_target >>
-    steps:
-      - checkout
-      - run:
-          name: Install dependencies
-          command: |
-            xcodebuild -downloadComponent MetalToolchain
-            mkdir -p ~/miniconda3
-            curl https://repo.anaconda.com/miniconda/Miniconda3-latest-MacOSX-arm64.sh -o ~/miniconda3/miniconda.sh
-            bash ~/miniconda3/miniconda.sh -b -u -p ~/miniconda3
-            rm ~/miniconda3/miniconda.sh
-            source ~/miniconda3/bin/activate
-            conda init --all
-            conda create -n env python=<< parameters.python_version >> -y
-            conda activate env
-            pip install --upgrade cmake
-            pip install nanobind==2.4.0
-            pip install --upgrade setuptools
-            pip install numpy
-            pip install twine
-            pip install build
-      - run:
-          name: Install Python package
-          command: |
-            conda activate env
-            env -u MACOSX_DEPLOYMENT_TARGET DEV_RELEASE=1 \
-              pip install . -v
-      - run:
-          name: Generate package stubs
-          command: |
-            conda activate env
-            pip install typing_extensions
-            python setup.py generate_stubs
-      - run:
-          name: Build Python package
-          command: |
-            conda activate env
-            python setup.py clean --all
-            << parameters.build_env >> MLX_BUILD_STAGE=1 python -m build -w
-      - when:
-          condition:
-            equal: ["3.10", << parameters.python_version >>]
-          steps:
-            - run:
-                name: Build common package
-                command: |
-                  conda activate env
-                  python setup.py clean --all
-                  << parameters.build_env >> MLX_BUILD_STAGE=2 python -m build -w
-      - when:
-          condition: << parameters.build_env >>
-          steps:
-            - run:
-                name: Upload package
-                command: |
-                  conda activate env
-                  twine upload dist/*
-      - store_artifacts:
-          path: dist/
-
-  build_linux_release:
-    parameters:
-      python_version:
-        type: string
-        default: "3.10"
-      build_env:
-        type: string
-        default: ""
-    machine:
-      image: ubuntu-2204:current
-      resource_class: large
-    steps:
-      - checkout
-      - run:
-          name: Build wheel
-          command: |
-            PYTHON=python<< parameters.python_version >>
-            export DEBIAN_FRONTEND=noninteractive
-            export NEEDRESTART_MODE=a
-            sudo apt-get update
-            TZ=Etc/UTC sudo apt-get -y install tzdata
-            sudo add-apt-repository -y ppa:deadsnakes/ppa
-            sudo apt-get install -y $PYTHON $PYTHON-dev $PYTHON-full
-            sudo apt-get install -y libblas-dev liblapack-dev liblapacke-dev
-            $PYTHON -m venv env
-            source env/bin/activate
-            pip install --upgrade pip
-            pip install --upgrade cmake
-            pip install auditwheel
-            pip install patchelf
-            pip install build
-            pip install twine
-            << parameters.build_env >> pip install ".[dev]" -v
-            pip install typing_extensions
-            python setup.py generate_stubs
-            python setup.py clean --all
-            MLX_BUILD_STAGE=1 << parameters.build_env >> python -m build -w
-            bash python/scripts/repair_linux.sh
-      - when:
-          condition:
-            equal: ["3.10", << parameters.python_version >>]
-          steps:
-            - run:
-                name: Build common package
-                command: |
-                  source env/bin/activate
-                  python setup.py clean --all
-                  << parameters.build_env >> MLX_BUILD_STAGE=2 \
-                    python -m build -w
-                  auditwheel repair dist/mlx_cpu*.whl --plat manylinux_2_35_x86_64
-      - when:
-          condition: << parameters.build_env >>
-          steps:
-            - run:
-                name: Upload packages
-                command: |
-                  source env/bin/activate
-                  twine upload wheelhouse/*.whl
-      - store_artifacts:
-          path: wheelhouse/
-
-  build_cuda_release:
-    parameters:
-      build_env:
-        type: string
-        default: ""
-    machine:
-      image: ubuntu-2204:current
-      resource_class: xlarge
-    steps:
-      - checkout
-      - run:
-          name: Build wheel
-          command: |
-            export DEBIAN_FRONTEND=noninteractive
-            export NEEDRESTART_MODE=a
-            wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2404/x86_64/cuda-keyring_1.1-1_all.deb
-            sudo dpkg -i cuda-keyring_1.1-1_all.deb
-            sudo apt-get update
-            sudo apt-get install cuda-toolkit-12-9 libcudnn9-dev-cuda-12
-            sudo apt-get install libblas-dev liblapack-dev liblapacke-dev
-            sudo apt-get install zip
-            pip install auditwheel
-            pip install patchelf
-            pip install build
-            pip install twine
-            export PATH=/usr/local/cuda/bin${PATH:+:${PATH}}
-            export LD_LIBRARY_PATH=/usr/local/cuda/lib64${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}
-            << parameters.build_env >> MLX_BUILD_STAGE=2 \
-              CMAKE_ARGS="-DMLX_BUILD_CUDA=ON -DCMAKE_CUDA_COMPILER=`which nvcc`" \
-              python -m build -w
-            bash python/scripts/repair_cuda.sh
-      - when:
-          condition: << parameters.build_env >>
-          steps:
-            - run:
-                name: Upload package
-                command: |
-                  twine upload wheelhouse/*.whl
-      - store_artifacts:
-          path: wheelhouse/
-
-workflows:
-  build_and_test:
-    when:
-      and:
-        - matches:
-            pattern: "^(?!pull/)[-\\w]+$"
-            value: << pipeline.git.branch >>
-        - not: << pipeline.parameters.nightly_build >>
-        - not: << pipeline.parameters.test_release >>
-    jobs:
-      - mac_build_and_test:
-          matrix:
-            parameters:
-              macosx_deployment_target: ["13.5", "15.0"]
-      - linux_build_and_test
-      - cuda_build_and_test:
-          matrix:
-            parameters:
-              image_date: ["2023.11.1", "2025.05.1"]
-      - build_documentation 
-
-  build_pypi_release:
-    when:
-      and:
-        - not: << pipeline.parameters.nightly_build >>
-        - not: << pipeline.parameters.test_release >>
-    jobs:
-      - build_release:
-          filters:
-            tags:
-              only: /^v.*/
-            branches:
-              ignore: /.*/
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-              macosx_deployment_target: ["13.5", "14.0", "15.0"]
-              build_env: ["PYPI_RELEASE=1"]
-              xcode_version: ["26.0.0"]
-      - build_documentation:
-          filters:
-            tags:
-              only: /^v.*/
-            branches:
-              ignore: /.*/
-          upload-docs: true
-      - build_linux_release:
-          filters:
-            tags:
-              only: /^v.*/
-            branches:
-              ignore: /.*/
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-              build_env: ["PYPI_RELEASE=1"]
-      - build_cuda_release:
-          filters:
-            tags:
-              only: /^v.*/
-            branches:
-              ignore: /.*/
-          matrix:
-            parameters:
-              build_env: ["PYPI_RELEASE=1"]
-
-  prb:
-    when:
-      matches:
-        pattern: "^pull/\\d+(/head)?$"
-        value: << pipeline.git.branch >>
-    jobs:
-      - hold:
-          type: approval
-      - apple/authenticate:
-          context: pr-approval
-      - mac_build_and_test:
-          requires: [ hold ]
-          matrix:
-            parameters:
-              macosx_deployment_target: ["13.5", "15.0"]
-      - linux_build_and_test:
-          requires: [ hold ]
-      - cuda_build_and_test:
-          requires: [ hold ]
-          matrix:
-            parameters:
-              image_date: ["2023.11.1", "2025.05.1"]
-  nightly_build:
-    when:
-      and:
-        - equal: [ main, << pipeline.git.branch >> ]
-        - << pipeline.parameters.nightly_build >>
-    jobs:
-      - build_release:
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-              macosx_deployment_target: ["13.5", "14.0", "15.0"]
-              xcode_version: ["26.0.0"]
-      - build_linux_release:
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-      - build_cuda_release
-
-  build_dev_release:
-    when:
-      and:
-        - equal: [ main, << pipeline.git.branch >> ]
-        - << pipeline.parameters.test_release >>
-    jobs:
-      - build_release:
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-              macosx_deployment_target: ["13.5", "14.0", "15.0"]
-              build_env: ["DEV_RELEASE=1"]
-              xcode_version: ["26.0.0"]
-      - build_linux_release:
-          matrix:
-            parameters:
-              python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-              build_env: ["DEV_RELEASE=1"]
-      - build_cuda_release:
-          matrix:
-            parameters:
-              build_env: ["DEV_RELEASE=1"]

.github/actions/build-cuda-release/action.yml

@@ -2,8 +2,8 @@ name: 'Build CUDA wheel'
 description: 'Build CUDA wheel'
 
 inputs:
-  nvcc-location:
-    description: 'Location of nvcc compiler'
+  toolkit:
+    description: 'The CUDA toolkit'
     required: true
 
 runs:
@@ -12,7 +12,7 @@ runs:
     - name: Build package
       shell: bash
       env:
-        CMAKE_ARGS: -DMLX_BUILD_CUDA=ON -DCMAKE_CUDA_COMPILER=${{ inputs.nvcc-location }}
+        CMAKE_ARGS: -DMLX_BUILD_CUDA=ON -DCMAKE_CUDA_COMPILER=/usr/local/${{ inputs.toolkit }}/bin/nvcc
       run: |
         pip install auditwheel build patchelf setuptools
         python setup.py clean --all

.github/actions/build-cuda/action.yml

@@ -2,10 +2,9 @@ name: 'Build and Test with CUDA'
 description: 'Build and test MLX with CUDA'
 
 inputs:
-  nvcc-location:
-    description: 'Location of nvcc compiler'
+  toolkit:
+    description: 'The CUDA toolkit'
     required: true
-    default: '/usr/local/cuda-12.9/bin/nvcc'
 
 runs:
   using: "composite"
@@ -14,32 +13,14 @@ runs:
       shell: bash
       env:
         DEBUG: 1
-        CMAKE_ARGS: -DMLX_BUILD_CUDA=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DCMAKE_CUDA_COMPILER=${{ inputs.nvcc-location }}
-      run: pip install -e ".[dev]" -v
-
-    - name: Run Python tests - CPU
-      shell: bash
-      env:
-        LOW_MEMORY: 1
-        DEVICE: cpu
-      run: python -m unittest discover python/tests -v
-
-    - name: Run Python tests - GPU
-      shell: bash
-      env:
-        LOW_MEMORY: 1
-        DEVICE: gpu
-      run: python -m tests discover python/tests -v
+        CMAKE_ARGS: -DMLX_BUILD_CUDA=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DCMAKE_CUDA_COMPILER=/usr/local/${{ inputs.toolkit }}/bin/nvcc
+      run: pip install --no-build-isolation -e ".[dev]" -v
 
     - name: Build CPP only
       shell: bash
       run: |
         cmake . -B build \
           -DMLX_BUILD_CUDA=ON \
-          -DCMAKE_CUDA_COMPILER=${{ inputs.nvcc-location }} \
+          -DCMAKE_CUDA_COMPILER=/usr/local/${{ inputs.toolkit }}/bin/nvcc \
           -DCMAKE_BUILD_TYPE=DEBUG
         cmake --build build -j $(nproc)
-    
-    - name: Run CPP tests
-      shell: bash
-      run: ./build/tests/tests -sfe="*fft_tests.cpp,*linalg_tests.cpp"

.github/actions/build-docs/action.yml

@@ -1,19 +1,19 @@
 name: 'Build Documentation'
-description: 'Build documentation on a mac'
+description: 'Build documentation'
 
 runs:
   using: "composite"
   steps:
     - name: Setup machine
-      uses: ./.github/actions/setup-macos
+      uses: ./.github/actions/setup-linux
 
     - name: Install dependencies
-      shell: sh
+      shell: bash
       run: |
-        brew install doxygen
-        uv pip install --upgrade pip cmake
-        uv pip install -r docs/requirements.txt
-        uv pip install . -v
+        sudo apt-get install -y doxygen
+        source .venv/bin/activate
+        pip install -r docs/requirements.txt
+        pip install . -v
   
     - name: Build documentation
       shell: bash
@@ -24,8 +24,8 @@ runs:
         make html O=-W
     
     - name: Create artifact tar
-      shell: sh
-      run: tar -cf artifact.tar --cd docs --dereference build/html index.html
+      shell: bash
+      run: tar -cf artifact.tar -C docs --dereference build/html index.html
 
     # Do it manually because upload-pages-artifact requires gtar
     - name: Upload artifact
@@ -35,4 +35,4 @@ runs:
         name: github-pages
         path: artifact.tar
         retention-days: 1
-        if-no-files-found: error
+        if-no-files-found: error

.github/actions/build-linux-release/action.yml

@@ -7,6 +7,13 @@ inputs:
     type: boolean
     required: false
     default: false
+  arch:
+    description: 'Platform architecture tag'
+    required: true
+    type: choice
+    options:
+      - x86_64
+      - aarch64
 
 runs:
   using: "composite"
@@ -23,11 +30,11 @@ runs:
         pip install auditwheel patchelf build
         python setup.py clean --all
         MLX_BUILD_STAGE=1 python -m build -w
-        bash python/scripts/repair_linux.sh
+        bash python/scripts/repair_linux.sh ${{ inputs.arch }}
     - name: Build backend package
       if: ${{ inputs.build-backend }}
       shell: bash
       run: |
         python setup.py clean --all
         MLX_BUILD_STAGE=2 python -m build -w
-        auditwheel repair dist/mlx_cpu*.whl --plat manylinux_2_35_x86_64
+        auditwheel repair dist/mlx_cpu*.whl --plat manylinux_2_35_${{ inputs.arch }}

.github/actions/build-linux/action.yml

@@ -9,33 +9,17 @@ runs:
       env:
         CMAKE_ARGS: "-DCMAKE_COMPILE_WARNING_AS_ERROR=ON"
         DEBUG: 1
-      run: pip install -e ".[dev]" -v
-    
+      run: pip install --no-build-isolation -e ".[dev]" -v
+
     - name: Generate package stubs
       shell: sh
       run: |
         pip install typing_extensions
         python setup.py generate_stubs
     
-    - name: Run Python tests
-      shell: bash
-      run: |
-        python -m unittest discover python/tests -v
-        mpirun --bind-to none --allow-run-as-root -host localhost:8 -np 8 python python/tests/mpi_test_distributed.py
-        mlx.launch --verbose -n 8 python/tests/ring_test_distributed.py -v 2> >(tee -a stderr.log >&2)
-        if grep -Fq '[WARN]' stderr.log ; then
-          grep -F '[WARN]' stderr.log
-          echo "Distributed ring test failed";
-          exit 1;
-        fi
-    
     - name: Build CPP only
       shell: bash
       run: |
         mkdir -p build && cd build
         cmake .. -DMLX_BUILD_METAL=OFF -DCMAKE_BUILD_TYPE=DEBUG
         make -j $(nproc)
-    
-    - name: Run CPP tests
-      shell: sh
-      run: ./build/tests/tests

.github/actions/build-macos-release/action.yml

@@ -16,18 +16,19 @@ runs:
   using: "composite"
   steps:
     - name: Build Python package
-      shell: bash
+      shell: bash -l {0}
       env:
         MACOSX_DEPLOYMENT_TARGET: ${{ inputs.macos-target }}
       run: |
-        uv pip install build
-        uv run --no-project setup.py clean --all
-        MLX_BUILD_STAGE=1 uv run -m build -w
+        pip install build
+        python setup.py clean --all
+        MLX_BUILD_STAGE=1 python -m build -w
+
     - name: Build backend package
       if: ${{ inputs.build-backend }}
-      shell: bash
+      shell: bash -l {0}
       env:
         MACOSX_DEPLOYMENT_TARGET: ${{ inputs.macos-target }}
       run: |
-        uv run --no-project setup.py clean --all
-        MLX_BUILD_STAGE=2 uv run -m build -w
+        python setup.py clean --all
+        MLX_BUILD_STAGE=2 python -m build -w

.github/actions/build-macos/action.yml

@@ -5,47 +5,47 @@ runs:
   using: "composite"
   steps:
     - name: Install dependencies
-      shell: sh
       env:
         DEBUG: 1
         CMAKE_ARGS: "-DCMAKE_COMPILE_WARNING_AS_ERROR=ON"
+      shell: bash -l {0}
       run: |
-        uv pip install --upgrade pip
-        uv pip install cmake setuptools nanobind==2.4.0
-        uv pip install -e . -v
+        pip install --upgrade pip
+        pip install cmake setuptools nanobind==2.4.0
+        pip install -e . -v
 
     - name: Generate package stubs
-      shell: bash
+      shell: bash -l {0}
       run: |
-        uv pip install typing_extensions
-        uv run --no-project setup.py generate_stubs
+        pip install typing_extensions
+        python setup.py generate_stubs
 
     - name: Install tests dependencies
-      shell: sh
+      shell: bash -l {0}
       run: |
-        uv pip install numpy torch tensorflow unittest-xml-reporting
+        pip install numpy torch tensorflow unittest-xml-reporting
 
     - name: Run Python tests
-      shell: bash
+      shell: bash -l {0}
       env:
         LOW_MEMORY: 1
       run: |
-        DEVICE=cpu uv run -m xmlrunner discover -v python/tests -o test-results/cpu
-        DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 uv run -m xmlrunner discover -v python/tests -o test-results/gpu
+        DEVICE=cpu python -m xmlrunner discover -v python/tests -o test-results/cpu
+        DEVICE=gpu METAL_DEVICE_WRAPPER_TYPE=1 METAL_DEBUG_ERROR_MODE=0 python -m xmlrunner discover -v python/tests -o test-results/gpu
         mpirun --bind-to none -host localhost:8 -np 8 -x DYLD_LIBRARY_PATH=/opt/homebrew/lib/ python python/tests/mpi_test_distributed.py
         mlx.launch --verbose -n 8 python/tests/ring_test_distributed.py -v 2> >(tee -a stderr.log >&2)
         if $(grep "\[WARN\]" stderr.log); then echo "Distributed ring test failed"; exit 1; fi
     
     - name: Build example extension
-      shell: bash
+      shell: bash -l {0}
       run: |
         cd examples/extensions
-        uv pip install -r requirements.txt
-        uv run --no-project setup.py build_ext --inplace
-        uv run --no-project test.py
+        pip install -r requirements.txt
+        python setup.py build_ext --inplace
+        python test.py
     
     - name: Build CPP only
-      shell: bash
+      shell: bash -l {0}
       run: |
         mkdir -p build
         cd build
@@ -53,7 +53,7 @@ runs:
         make -j $(sysctl -n hw.ncpu)
     
     - name: Run CPP tests
-      shell: bash
+      shell: bash -l {0}
       env:
         DEVICE: gpu
         METAL_DEVICE_WRAPPER_TYPE: 1
@@ -61,7 +61,7 @@ runs:
       run: ./build/tests/tests
     
     - name: Build small binary with JIT
-      shell: bash
+      shell: bash -l {0}
       run: |
         mkdir -p build
         cd build
@@ -74,7 +74,7 @@ runs:
         make -j $(sysctl -n hw.ncpu)
     
     - name: Run Python tests with JIT
-      shell: bash
+      shell: bash -l {0}
       env:
         LOW_MEMORY: 1
         DEVICE: gpu
@@ -82,7 +82,7 @@ runs:
         METAL_DEBUG_ERROR_MODE: 0
       run: |
         CMAKE_ARGS="-DMLX_METAL_JIT=ON" \
-          uv pip install -e . -v
-        uv run -m xmlrunner discover \
+          pip install -e . -v
+        python -m xmlrunner discover \
             -v python/tests \
             -o test-results/gpu_jit

.github/actions/setup-linux/action.yml

@@ -2,14 +2,10 @@ name: 'Setup Linux Environment'
 description: 'Install dependencies for Linux builds'
 
 inputs:
-  runner-type:
-    description: 'Whether to set this up as a linux or CUDA runner'
+  toolkit:
+    description: 'Which toolkit to install'
     required: false
-    default: 'linux'
-    type: choice
-    options:
-      - linux
-      - cuda
+    default: 'cpu'
   python-version:
     description: 'Version of python to set up'
     required: false
@@ -18,56 +14,62 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: Free disk space
-      shell: sh
-      if: inputs.runner-type == 'linux'
-      run: sudo rm -rf "$AGENT_TOOLSDIRECTORY"
+    - name: Use ccache
+      uses: hendrikmuhs/ccache-action@v1.2
+      with:
+        key: ccache-${{ runner.os }}-${{ runner.arch }}-${{ inputs.toolkit }}-py${{ inputs.python-version }}
+        max-size: 1GB
 
     - name: Install common dependencies
-      env:
-        TZ: Etc/UTC
       shell: bash
       run: |
         sudo apt-get update
-        sudo apt-get install -y libblas-dev liblapack-dev liblapacke-dev tzdata zip
-        sudo apt autoremove -y
+        sudo apt-get install -y libblas-dev liblapack-dev liblapacke-dev zip
 
     - uses: actions/setup-python@v6
       with:
         python-version: ${{ inputs.python-version }}
-        cache: 'pip'
 
-    - name: setup python venv
+    - name: Setup Python venv
       shell: bash
       run: |
         python -m venv .venv
         source .venv/bin/activate
+        pip install setuptools cmake nanobind==2.4.0
         echo PATH=$PATH >> $GITHUB_ENV
-        pip install --upgrade pip cmake
+        # Make cmake search .venv for nanobind
+        echo PYTHONPATH=`python -c 'import sys; print(sys.path[-1])'` >> $GITHUB_ENV
 
     - name: Install MPI
-      if: inputs.runner-type == 'linux'
       shell: bash
       run: sudo apt-get install -y openmpi-bin openmpi-common libopenmpi-dev
 
-    - name: Network CUDA installation from packages
-      id: install-cuda
-      if: inputs.runner-type == 'cuda'
+    - name: Install CUDA toolkit
+      if: ${{ startsWith(inputs.toolkit, 'cuda') }}
+      shell: bash
       env:
-        TZ: Etc/UTC
-      shell: bash ## Specific to Ubuntu 22.04 & Architecture x86_64
+        # Note: the CI machine does not meet CUDA 13's driver requirement.
+        # Compatibility matrix:
+        # https://docs.nvidia.com/deeplearning/cudnn/backend/latest/reference/support-matrix.html
+        # The `nvcc` is installed into `/usr/local/cuda-VERSION/bin/nvcc` - but
+        # it's *not* on the default toolkit path.
+        PACKAGES: |
+          {
+            "cuda-12.6": "libcudnn9-dev-cuda-12 cuda-toolkit-12-6",
+            "cuda-12.9": "libcudnn9-dev-cuda-12 cuda-toolkit-12-9",
+            "cuda-13.0": "libcudnn9-dev-cuda-13 cuda-toolkit-13-0"
+          }
       run: |
-        wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2204/x86_64/cuda-keyring_1.1-1_all.deb
+        export ARCH=${{ runner.arch == 'arm64' && 'arm64' || 'x86_64' }}
+        wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2204/$ARCH/cuda-keyring_1.1-1_all.deb
         sudo dpkg -i cuda-keyring_1.1-1_all.deb
         sudo apt-get update
-        sudo apt-get install -y libcudnn9-dev-cuda-12 libnccl2 libnccl-dev cuda-toolkit-12-9
-      # Note: This installs CUDA 12.9, which is the latest supported by cuDNN 9.x and works with the NVidia 570 drivers
-      # cuda-toolkit by itself installs version 13 (+) and requires updated drives (580+), which require a reboot to function properly.
-      # Compatibility matrix: https://docs.nvidia.com/deeplearning/cudnn/backend/latest/reference/support-matrix.html
-      # This also drops `nvcc` into `/usr/local/cuda-12.9/bin/nvcc` - but it's *not* on the default PATH
+        sudo apt-get install -y \
+            libnccl2 libnccl-dev \
+            ${{ fromJson(env.PACKAGES)[inputs.toolkit] }}
 
-    - name: Package and Driver Report
-      if: inputs.runner-type == 'cuda'
+    - name: CUDA packages and driver report
+      if: ${{ startsWith(inputs.toolkit, 'cuda') }}
       shell: bash
       run: |
         sudo apt-get install -y ubuntu-drivers-common dkms

.github/actions/setup-macos/action.yml

@@ -17,9 +17,8 @@ runs:
     - name: Verify MetalToolchain installed
       shell: bash
       run: xcodebuild -showComponent MetalToolchain
-    
-    - name: Setup uv
-      uses: astral-sh/setup-uv@v6
+
+    - uses: conda-incubator/setup-miniconda@v3
       with:
-          python-version: ${{ inputs.python-version }}
-          activate-environment: true
+        miniconda-version: "latest"
+        python-version: ${{ inputs.python-version }}

.github/actions/test-linux/action.yml

@@ -0,0 +1,69 @@
+name: 'Run Linux tests'
+
+inputs:
+  cpu-only:
+    description: 'Skip GPU tests'
+    required: false
+    default: false
+
+runs:
+  using: "composite"
+  steps:
+    - name: Run MPI tests
+      shell: bash
+      run: |
+        echo "::group::MPI tests"
+        mpirun --bind-to none --allow-run-as-root -host localhost:8 -np 8 python python/tests/mpi_test_distributed.py
+        echo "::endgroup::"
+
+    - name: Run distributed tests
+      if: ${{ inputs.cpu-only == 'true' }}
+      shell: bash
+      run: |
+        echo "::group::Distributed tests"
+        mlx.launch --verbose -n 8 python/tests/ring_test_distributed.py -v 2> >(tee -a stderr.log >&2)
+        if grep -Fq '[WARN]' stderr.log ; then
+          grep -F '[WARN]' stderr.log
+          echo "Distributed ring test failed";
+          exit 1;
+        fi
+        echo "::endgroup::"
+
+    - name: Run Python tests - CPU
+      if: ${{ inputs.cpu-only == 'true' }}
+      shell: bash
+      env:
+        DEVICE: cpu
+      run: |
+        echo "::group::Python tests - CPU"
+        python -m unittest discover python/tests -v
+        echo "::endgroup::"
+
+    - name: Run Python tests - GPU
+      if: ${{ inputs.cpu-only == 'false' }}
+      shell: bash
+      env:
+        DEVICE: gpu
+      run: |
+        echo "::group::Python tests - GPU"
+        python -m tests discover python/tests -v
+        echo "::endgroup::"
+
+    - name: Run CPP tests - CPU
+      shell: bash
+      env:
+        DEVICE: cpu
+      run: |
+        echo "::group::CPP tests - CPU"
+        ./build/tests/tests
+        echo "::endgroup::"
+
+    - name: Run CPP tests - GPU
+      if: ${{ inputs.cpu-only == 'false' }}
+      shell: bash
+      env:
+        DEVICE: gpu
+      run: |
+        echo "::group::CPP tests - GPU"
+        ./build/tests/tests -sfe="*fft_tests.cpp,*linalg_tests.cpp"
+        echo "::endgroup::"

.github/workflows/documentation.yml

@@ -8,7 +8,7 @@ permissions:
 
 jobs:
   build:
-    runs-on: [self-hosted, macos]
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/build-docs
@@ -25,4 +25,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v4

.github/workflows/nightly.yml

@@ -21,6 +21,7 @@ jobs:
       - uses: ./.github/actions/build-linux-release
         with:
           build-backend: ${{ matrix.python-version == '3.10' }}
+          arch: "x86_64"
       - name: Upload mlx artifacts
         uses: actions/upload-artifact@v5
         with:
@@ -34,19 +35,25 @@ jobs:
           name: mlx-cpu
           path: wheelhouse/mlx_cpu-*.whl
           retention-days: 7
-  
+
   build_linux_with_tests:
     strategy:
       fail-fast: false
       matrix:
-        python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-    runs-on: ubuntu-22.04
+        python_version: ["3.11", "3.12", "3.13", "3.14"]
+        runner:
+          - ubuntu-22.04
+          - ubuntu-22.04-arm
+    runs-on: ${{ matrix.runner }}
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
         with:
           python-version: ${{ matrix.python_version }}
       - uses: ./.github/actions/build-linux
+      - uses: ./.github/actions/test-linux
+        with:
+          cpu-only: true
 
   build_mac_release:
     if: github.repository == 'ml-explore/mlx'
@@ -60,7 +67,6 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
       - uses: ./.github/actions/build-macos
-
       - name: Build macOS 15 package
         uses: ./.github/actions/build-macos-release
         with:
@@ -72,16 +78,6 @@ jobs:
           macos-target: 14.0
           build-backend: ${{ matrix.python-version == '3.10' }}
 
-  build_cuda_with_tests:
-    if: github.repository == 'ml-explore/mlx'
-    runs-on: gpu-t4-4-core
-    steps:
-      - uses: actions/checkout@v5
-      - uses: ./.github/actions/setup-linux
-        with:
-          runner-type: 'cuda'
-      - uses: ./.github/actions/build-cuda
-
   build_cuda_release:
     if: github.repository == 'ml-explore/mlx'
     runs-on: ubuntu-22-large
@@ -89,36 +85,14 @@ jobs:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
         with:
-          runner-type: 'cuda'
+          toolkit: 'cuda-12.9'
       - name: Build Python package
         uses: ./.github/actions/build-cuda-release
         with:
-          nvcc-location: '/usr/local/cuda-12.9/bin/nvcc'
+          toolkit: 'cuda-12.9'
       - name: Upload artifacts
         uses: actions/upload-artifact@v5
         with:
           name: mlx-cuda
           path: wheelhouse/mlx_cuda-*.whl
           retention-days: 7
-
-  linux_fedora_build_cpp:
-    name: Linux Fedora CPP Build (${{ matrix.arch }})
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - host: ubuntu-22.04
-            arch: x86_64
-          - host: ubuntu-22.04-arm
-            arch: aarch64
-
-    runs-on: ${{ matrix.host }}
-    container:
-      image: fedora:42
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v5
-
-      - name: CPP Build Test - No Release
-        run: |
-          bash ./.github/scripts/setup+build-cpp-linux-fedora-container.sh

.github/workflows/pull_request.yml

@@ -1,28 +1,52 @@
 name: Build and Test
 
-on: pull_request  
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+      # For testing CI without starting a pull request:
+      - test/*
 
 permissions:
   contents: read
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/head/main' }}
+
 jobs:
   check_lint:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v5
-      - uses: ./.github/actions/setup-linux
       - uses: pre-commit/action@v3.0.1
 
   linux_build_and_test:
-    runs-on: ubuntu-22.04
+    needs: check_lint
+    strategy:
+      matrix:
+        runner:
+          - ubuntu-22.04
+          - ubuntu-22.04-arm
+      fail-fast: false
+    runs-on: ${{ matrix.runner }}
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
       - uses: ./.github/actions/build-linux
+      - uses: ./.github/actions/test-linux
+        with:
+          cpu-only: true
 
   mac_build_and_test:
     if: github.repository == 'ml-explore/mlx'
+    strategy:
+      matrix:
+        macos-target: ["14.0", "15.0"]
     runs-on: [self-hosted, macos]
+    env:
+      MACOSX_DEPLOYMENT_TARGET: ${{ matrix.macos-target }}
     needs: check_lint
     steps:
       - uses: actions/checkout@v5
@@ -31,18 +55,25 @@ jobs:
 
   cuda_build_and_test:
     if: github.repository == 'ml-explore/mlx'
+    strategy:
+      fail-fast: false
+      matrix:
+        toolkit: ['cuda-12.6', 'cuda-12.9']
     runs-on: gpu-t4-4-core
     needs: check_lint
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
         with:
-          runner-type: 'cuda'
+          toolkit: ${{ matrix.toolkit }}
       - uses: ./.github/actions/build-cuda
+        with:
+          toolkit: ${{ matrix.toolkit }}
+      - uses: ./.github/actions/test-linux
 
   build_documentation:
     if: github.repository == 'ml-explore/mlx'
-    runs-on: [self-hosted, macos]
+    runs-on: ubuntu-22.04
     needs: check_lint
     steps:
       - uses: actions/checkout@v5
@@ -50,6 +81,7 @@ jobs:
 
   linux_fedora_build_cpp:
     name: Linux Fedora CPP Build (${{ matrix.arch }})
+    needs: check_lint
     strategy:
       fail-fast: false
       matrix:

.github/workflows/release.yml

@@ -5,6 +5,11 @@ on:
     tags:
       - 'v*'
   workflow_dispatch:
+    inputs:
+      dev_release:
+        description: "Do a dev release or regular release"
+        required: true
+        default: "false"
 
 permissions:
   contents: read
@@ -12,16 +17,13 @@ permissions:
 jobs:
   setup:
     runs-on: ubuntu-latest
-    outputs:
-      pypi_env: ${{ github.event_name == 'push' && 'pypi' || 'test-pypi' }}
-      pypi_url: ${{ github.event_name == 'push' && 'https://upload.pypi.org/legacy/' || 'https://test.pypi.org/legacy/' }}
     steps:
       - name: Set publishing variables
         run: echo "Publishing setup complete"
 
   build_documentation:
     if: github.repository == 'ml-explore/mlx'
-    runs-on: [self-hosted, macos]
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/build-docs
@@ -45,9 +47,11 @@ jobs:
     strategy:
       matrix:
         python_version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-    runs-on: ubuntu-22.04
+        arch: ['x86_64', 'aarch64']
+    runs-on: ${{ matrix.arch == 'x86_64' && 'ubuntu-22.04' || 'ubuntu-22.04-arm' }}
     env:
       PYPI_RELEASE: 1
+      DEV_RELEASE: ${{ github.event.inputs.dev_release == 'true' && 1 || 0 }}
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
@@ -56,16 +60,19 @@ jobs:
       - uses: ./.github/actions/build-linux-release
         with:
           build-backend: ${{ matrix.python-version == '3.10' }}
+          arch: ${{ matrix.arch }}
       - name: Upload MLX artifacts
         uses: actions/upload-artifact@v5
         with:
-          name: linux-wheels-${{ matrix.python_version }}
+          overwrite: true
+          name: linux-wheels-${{ matrix.python_version }}-${{ matrix.arch }}
           path: wheelhouse/mlx-*.whl
       - name: Upload CPU artifacts
         if: matrix.python_version == '3.10'
         uses: actions/upload-artifact@v5
         with:
-          name: mlx-cpu
+          overwrite: true
+          name: mlx-cpu-${{ matrix.arch }}
           path: wheelhouse/mlx_cpu-*.whl
   
   build_mac_release:
@@ -76,22 +83,25 @@ jobs:
     runs-on: [self-hosted, macos]
     env:
       PYPI_RELEASE: 1
+      DEV_RELEASE: ${{ github.event.inputs.dev_release == 'true' && 1 || 0 }}
+
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-macos
         with:
           python-version: ${{ matrix.python-version }}
+
       - name: Install dependencies
-        shell: sh
+        shell: bash -l {0}
         run: |
-          uv pip install --upgrade pip
-          uv pip install cmake setuptools nanobind==2.4.0
-          uv pip install -e . -v
+          pip install --upgrade pip
+          pip install cmake setuptools nanobind==2.4.0
+          pip install -e . -v
       - name: Generate package stubs
-        shell: bash
+        shell: bash -l {0}
         run: |
-          uv pip install typing_extensions
-          uv run --no-project setup.py generate_stubs
+          pip install typing_extensions
+          python setup.py generate_stubs
       - name: Build macOS 14 package
         uses: ./.github/actions/build-macos-release
         with:
@@ -105,12 +115,14 @@ jobs:
       - name: Upload MLX artifacts
         uses: actions/upload-artifact@v5
         with:
+          overwrite: true
           name: mac-wheels-${{ matrix.python-version }}
           path: dist/mlx-*.whl
       - name: Upload Metal artifacts
         if: matrix.python-version == '3.10'
         uses: actions/upload-artifact@v5
         with:
+          overwrite: true
           name: mlx-metal
           path: dist/mlx_metal-*.whl
 
@@ -119,18 +131,20 @@ jobs:
     runs-on: ubuntu-22-large
     env:
       PYPI_RELEASE: 1
+      DEV_RELEASE: ${{ github.event.inputs.dev_release == 'true' && 1 || 0 }}
     steps:
       - uses: actions/checkout@v5
       - uses: ./.github/actions/setup-linux
         with:
-          runner-type: 'cuda'
+          toolkit: 'cuda-12.9'
       - name: Build Python package
         uses: ./.github/actions/build-cuda-release
         with:
-          nvcc-location: '/usr/local/cuda-12.9/bin/nvcc'
+          toolkit: 'cuda-12.9'
       - name: Upload artifacts
         uses: actions/upload-artifact@v5
         with:
+          overwrite: true
           name: mlx-cuda
           path: wheelhouse/mlx_cuda-*.whl
 
@@ -141,7 +155,7 @@ jobs:
     permissions:
       id-token: write
     environment:
-      name: ${{ needs.setup.outputs.pypi_env }}
+      name: pypi
       url: https://pypi.org/p/mlx
     steps:
       - uses: actions/download-artifact@v6
@@ -159,7 +173,7 @@ jobs:
       - name: Publish package distributions to PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
-          repository-url: ${{ needs.setup.outputs.pypi_url }}
+          repository-url: https://upload.pypi.org/legacy/
   
   pypi-publish-cuda:
     name: Upload CUDA release to PyPI
@@ -168,7 +182,7 @@ jobs:
     permissions:
       id-token: write
     environment:
-      name: ${{ needs.setup.outputs.pypi_env }}
+      name: pypi
       url: https://pypi.org/p/mlx-cuda
     steps:
       - uses: actions/download-artifact@v6
@@ -180,7 +194,7 @@ jobs:
       - name: Publish package distributions to PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
-          repository-url: ${{ needs.setup.outputs.pypi_url }}
+          repository-url: https://upload.pypi.org/legacy/
 
   pypi-publish-cpu:
     name: Upload CPU release to PyPI
@@ -189,19 +203,20 @@ jobs:
     permissions:
       id-token: write
     environment:
-      name: ${{ needs.setup.outputs.pypi_env }}
+      name: pypi
       url: https://pypi.org/p/mlx-cpu
     steps:
       - uses: actions/download-artifact@v6
         with:
-          name: mlx-cpu
+          pattern: mlx-cpu-*
+          merge-multiple: true
           path: dist
       - name: Display structure of downloaded files
         run: ls -R dist
       - name: Publish package distributions to PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
-          repository-url: ${{ needs.setup.outputs.pypi_url }}
+          repository-url: https://upload.pypi.org/legacy/
 
   pypi-publish-metal:
     name: Upload Metal release to PyPI
@@ -210,7 +225,7 @@ jobs:
     permissions:
       id-token: write
     environment:
-      name: ${{ needs.setup.outputs.pypi_env }}
+      name: pypi
       url: https://pypi.org/p/mlx-metal
     steps:
       - uses: actions/download-artifact@v6
@@ -222,5 +237,4 @@ jobs:
       - name: Publish package distributions to PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
-          repository-url: ${{ needs.setup.outputs.pypi_url }}
-
+          repository-url: https://upload.pypi.org/legacy/

CMakeLists.txt

@@ -74,6 +74,7 @@ endif()
 if(MLX_USE_CCACHE)
   find_program(CCACHE_PROGRAM ccache)
   if(CCACHE_PROGRAM)
+    message(STATUS "Found CCache: ${CCACHE_PROGRAM}")
     set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
     set(CMAKE_CXX_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
     set(CMAKE_CUDA_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")

benchmarks/cpp/irregular_strides.cpp

@@ -75,7 +75,7 @@ void time_irregular_binary_ops_3D() {
 
 void time_irregular_binary_ops_4D() {
   auto device = mx::default_device();
-  std::vector<int> shape = {8, 8, 512, 512};
+  mx::Shape shape = {8, 8, 512, 512};
   auto a = mx::random::uniform(shape);
   auto b = mx::random::uniform(shape);
 
@@ -115,7 +115,7 @@ void time_irregular_binary_ops_4D() {
 
 void time_irregular_reshape() {
   auto device = mx::default_device();
-  std::vector<int> shape;
+  mx::Shape shape;
   auto reshape_fn = [&shape, device](const mx::array& a) {
     return mx::reshape(a, shape, device);
   };
@@ -170,7 +170,7 @@ void time_irregular_astype_1D() {
 void time_irregular_astype_2D() {
   auto device = mx::default_device();
   int size = 2048;
-  std::vector<int> shape = {size, size};
+  mx::Shape shape = {size, size};
 
   auto a = mx::random::uniform(shape);
   TIMEM("2D regular", mx::astype, a, mx::int32, device);

benchmarks/python/blas/bench_gemv.py

@@ -1,6 +1,5 @@
 # Copyright © 2023 Apple Inc.
 
-import argparse
 import os
 import subprocess
 import time

benchmarks/python/masked_scatter.py

@@ -0,0 +1,212 @@
+import math
+import os
+import subprocess
+import time
+from copy import copy
+from functools import partial
+
+import matplotlib.pyplot as plt
+import mlx.core as mx
+import numpy as np
+import torch
+from matplotlib.ticker import FuncFormatter
+
+RESULTS_DIR = "./results"
+
+
+if not os.path.isdir(RESULTS_DIR):
+    os.mkdir(RESULTS_DIR)
+
+DEVICE_NAME = subprocess.check_output(["sysctl", "-n", "machdep.cpu.brand_string"])
+DEVICE_NAME = DEVICE_NAME.decode("utf-8").strip("\n")
+
+TORCH_DEVICE = torch.device(
+    "mps"
+    if torch.backends.mps.is_available()
+    else ("cuda" if torch.cuda.is_available() else "cpu")
+)
+
+
+N_WARMUP = 5
+N_ITER_BENCH = 50
+N_ITER_FUNC = 20
+
+VECTOR_LENGTHS = [4096 * (2**i) for i in range(10)]
+MASK_DENSITIES = [0.01, 0.1, 0.25, 0.5]
+D_TYPES = ("float32", "float16")
+
+
+def _power_of_two_formatter(value, _position):
+    if value <= 0:
+        return ""
+    exponent = int(round(math.log2(value)))
+    if abs(value - (1 << exponent)) / value > 1e-6:
+        return f"{value:g}"
+    return f"$2^{{{exponent}}}$"
+
+
+def torch_sync():
+    if TORCH_DEVICE.type == "cuda":
+        torch.cuda.synchronize()
+    elif TORCH_DEVICE.type == "mps":
+        torch.mps.synchronize()
+
+
+def masked_scatter_mlx(self_arr, mask_arr, src_arr):
+    outs = []
+    for _ in range(N_ITER_FUNC):
+        out = copy(self_arr)
+        out[mask_arr] = src_arr
+        outs.append(out)
+    mx.eval(outs)
+    return outs
+
+
+@torch.no_grad()
+def masked_scatter_torch(self_tensor, mask_tensor, src_tensor):
+    outs = []
+    for _ in range(N_ITER_FUNC):
+        out = self_tensor.clone()
+        out.masked_scatter_(mask_tensor, src_tensor)
+        outs.append(out)
+    torch_sync()
+    return outs
+
+
+def measure(fn):
+    for _ in range(N_WARMUP):
+        fn()
+    start = time.perf_counter_ns()
+    for _ in range(N_ITER_BENCH):
+        fn()
+    end = time.perf_counter_ns()
+    return (end - start) * 1e-9
+
+
+def bytes_touched(length, true_count, item_size):
+    mask_bytes = length
+    self_bytes = length * item_size * 2  # read + write
+    src_bytes = true_count * item_size
+    return (mask_bytes + self_bytes + src_bytes) * N_ITER_FUNC * N_ITER_BENCH
+
+
+def build_case(length, density, np_dtype, torch_dtype):
+    true_count = max(1, int(round(length * density)))
+
+    rng = np.random.default_rng()
+    self_np = rng.normal(0.0, 1.0, length).astype(np_dtype)
+    mask_np = np.zeros(length, dtype=bool)
+    mask_np[:true_count] = True
+    rng.shuffle(mask_np)
+    src_np = rng.normal(0.0, 1.0, true_count).astype(np_dtype)
+
+    self_mlx = mx.array(self_np)
+    mask_mlx = mx.array(mask_np)
+    src_mlx = mx.array(src_np)
+
+    self_torch = torch.from_numpy(self_np).to(device=TORCH_DEVICE, dtype=torch_dtype)
+    mask_torch = torch.from_numpy(mask_np).to(device=TORCH_DEVICE)
+    src_torch = torch.from_numpy(src_np).to(device=TORCH_DEVICE, dtype=torch_dtype)
+
+    # Correctness check once per configuration
+    mx_out = mx.array(self_np)
+    mx_out[mask_mlx] = src_mlx
+    mx.eval(mx_out)
+    torch_out = self_torch.clone()
+    torch_out.masked_scatter_(mask_torch, src_torch)
+
+    atol = 5e-3 if np_dtype == np.float16 else 1e-5
+    if not np.allclose(np.array(mx_out), torch_out.cpu().numpy(), atol=atol):
+        raise AssertionError("masked_scatter results diverged between MLX and Torch")
+
+    return (self_mlx, mask_mlx, src_mlx, self_torch, mask_torch, src_torch, true_count)
+
+
+def bench_case(length, density, dtype):
+    np_dtype = getattr(np, dtype)
+    torch_dtype = getattr(torch, dtype)
+    (
+        self_mlx,
+        mask_mlx,
+        src_mlx,
+        self_torch,
+        mask_torch,
+        src_torch,
+        true_count,
+    ) = build_case(length, density, np_dtype, torch_dtype)
+
+    time_mlx = measure(partial(masked_scatter_mlx, self_mlx, mask_mlx, src_mlx))
+    time_torch = measure(
+        partial(masked_scatter_torch, self_torch, mask_torch, src_torch)
+    )
+
+    total_bytes = bytes_touched(length, true_count, np_dtype().itemsize)
+    bytes_per_gb = float(1024**3)
+    mlx_gbps = (total_bytes / bytes_per_gb) / time_mlx
+    torch_gbps = (total_bytes / bytes_per_gb) / time_torch
+
+    return time_mlx, time_torch, mlx_gbps, torch_gbps
+
+
+def plot_density(ax_perf, ax_speedup, density, dtype):
+    mlx_gbps = []
+    torch_gbps = []
+    mlx_times = []
+    torch_times = []
+
+    for length in VECTOR_LENGTHS:
+        t_mlx, t_torch, gbps_mlx, gbps_torch = bench_case(length, density, dtype)
+        mlx_gbps.append(gbps_mlx)
+        torch_gbps.append(gbps_torch)
+        mlx_times.append(t_mlx)
+        torch_times.append(t_torch)
+
+    ax_perf.plot(VECTOR_LENGTHS, mlx_gbps, "tab:blue", label="MLX")
+    ax_perf.plot(VECTOR_LENGTHS, torch_gbps, "tab:red", label="Torch")
+    ax_perf.set_xscale("log", base=2)
+    ax_perf.set_xticks(VECTOR_LENGTHS)
+    formatter = FuncFormatter(_power_of_two_formatter)
+    ax_perf.xaxis.set_major_formatter(formatter)
+    ax_perf.set_title(f"density={density:.2f}")
+    ax_perf.set_ylabel("GB/s")
+    ax_perf.grid(True, which="both", linestyle=":", alpha=0.4)
+    ax_perf.legend()
+
+    speedup = np.array(torch_times) / np.array(mlx_times)
+    ax_speedup.plot(VECTOR_LENGTHS, speedup, "tab:green")
+    ax_speedup.axhline(1.0, color="tab:gray", linestyle="--")
+    ax_speedup.set_xscale("log", base=2)
+    ax_speedup.set_xticks(VECTOR_LENGTHS)
+    ax_speedup.xaxis.set_major_formatter(formatter)
+    ax_speedup.set_ylabel("Speedup (Torch_t / MLX_t)")
+    ax_speedup.grid(True, which="both", linestyle=":", alpha=0.4)
+
+
+def main():
+    for dtype in D_TYPES:
+        fig, axs = plt.subplots(
+            len(MASK_DENSITIES),
+            2,
+            figsize=(10, 12),
+            layout="constrained",
+            sharex=True,
+        )
+
+        for i, density in enumerate(MASK_DENSITIES):
+            plot_density(axs[i][0], axs[i][1], density, dtype)
+            axs[i][0].set_xlabel("vector length")
+            axs[i][1].set_xlabel("vector length")
+
+        fig.suptitle(
+            f"{DEVICE_NAME.replace('Apple ', '')} ({TORCH_DEVICE.type}) | dtype={dtype}"
+        )
+        output_path = os.path.join(
+            RESULTS_DIR,
+            f"{DEVICE_NAME.replace(' ', '_')}_masked_scatter_{dtype}.pdf",
+        )
+        fig.savefig(output_path)
+        plt.close(fig)
+
+
+if __name__ == "__main__":
+    main()

cmake/Findnvpl.cmake

@@ -0,0 +1,3 @@
+# This file does nothing but to suppress the cmake warning: "By not providing
+# Findnvpl.cmake in CMAKE_MODULE_PATH...", which is caused by the
+# find_package(nvpl) from cmake's builtin FindLAPACK.cmake module.

docs/src/usage/indexing.rst

@@ -70,7 +70,8 @@ Differences from NumPy
 
   * Indexing does not perform bounds checking. Indexing out of bounds is
     undefined behavior.
-  * Boolean mask based indexing is not yet supported.
+  * Boolean mask based indexing is supported for assignment only (see
+    :ref:`boolean-mask-assignment`).
 
 The reason for the lack of bounds checking is that exceptions cannot propagate
 from the GPU. Performing bounds checking for array indices before launching the
@@ -143,3 +144,51 @@ expected. For example:
 
 In the above ``dfdx`` will have the correct gradient, namely zeros at ``idx``
 and ones elsewhere.
+
+.. _boolean-mask-assignment:
+
+Boolean Mask Assignment
+-----------------------
+
+MLX supports boolean indices using NumPy syntax. A mask must already be
+a :class:`bool_` MLX :class:`array` or a NumPy ``ndarray`` with ``dtype=bool``.
+Other index types are routed through the standard scatter code.
+
+.. code-block:: shell
+
+   >>> a = mx.array([1.0, 2.0, 3.0])
+   >>> mask = mx.array([True, False, True])
+   >>> updates = mx.array([5.0, 6.0])
+   >>> a[mask] = updates
+   >>> a
+   array([5.0, 2.0, 6.0], dtype=float32)
+
+Scalar assignments broadcast to every ``True`` entry in ``mask``. For non-scalar
+assignments, ``updates`` must provide at least as many elements as there are
+``True`` entries in ``mask``.
+
+.. code-block:: shell
+
+   >>> a = mx.zeros((2, 3))
+   >>> mask = mx.array([[True, False, True],
+                        [False, False, True]])
+   >>> a[mask] = 1.0
+   >>> a
+   array([[1.0, 0.0, 1.0],
+          [0.0, 0.0, 1.0]], dtype=float32)
+
+Boolean masks follow NumPy semantics:
+
+- The mask shape must match the shape of the axes it indexes exactly. No mask
+  broadcasting occurs.
+- Any axes not covered by the mask are taken in full.
+
+.. code-block:: shell
+
+   >>> a = mx.arange(1000).reshape(10, 10, 10)
+   >>> a[mx.random.randn(10, 10) > 0.0] = 0  # valid: mask covers axes 0 and 1
+
+The mask of shape ``(10, 10)`` applies to the first two axes, so ``a[mask]``
+selects the 1-D slices ``a[i, j, :]`` where ``mask[i, j]`` is ``True``.
+Shapes such as ``(1, 10, 10)`` or ``(10, 10, 1)`` do not match the indexed
+axes and therefore raise errors.

mlx/array.cpp

@@ -167,7 +167,7 @@ void array::copy_shared_buffer(
     const Strides& strides,
     Flags flags,
     size_t data_size,
-    size_t offset /* = 0 */) {
+    int64_t offset /* = 0 */) {
   array_desc_->data = other.array_desc_->data;
   array_desc_->strides = strides;
   array_desc_->flags = flags;

mlx/array.h

@@ -439,7 +439,7 @@ class array {
       const Strides& strides,
       Flags flags,
       size_t data_size,
-      size_t offset = 0);
+      int64_t offset = 0);
 
   void copy_shared_buffer(const array& other);
 

mlx/backend/common/slicing.cpp

@@ -14,17 +14,13 @@ std::tuple<int64_t, Strides> prepare_slice(
     data_offset += start_indices[i] * in.strides()[i];
     inp_strides[i] = in.strides()[i] * strides[i];
   }
-  // Normalize the offset
-  if (data_offset < 0) {
-    data_offset += in.data_size();
-  }
   return std::make_tuple(data_offset, inp_strides);
 }
 
 void shared_buffer_slice(
     const array& in,
     const Strides& out_strides,
-    size_t data_offset,
+    int64_t data_offset,
     size_t data_size,
     array& out) {
   // Compute row/col contiguity
@@ -51,17 +47,24 @@ void slice(
 
   // Calculate out strides, initial offset
   auto [data_offset, inp_strides] = prepare_slice(in, start_indices, strides);
-  int64_t data_end = 1;
-  for (int i = 0; i < start_indices.size(); ++i) {
-    if (in.shape()[i] > 1) {
-      auto end_idx = start_indices[i] + out.shape()[i] * strides[i] - 1;
-      data_end += end_idx * in.strides()[i];
+
+  // Get the location of the end based on the inp strides and out.shape()
+  int64_t low_idx = 0;
+  int64_t high_idx = 0;
+  for (int i = 0; i < inp_strides.size(); ++i) {
+    auto delta = inp_strides[i] * (out.shape()[i] - 1);
+    if (inp_strides[i] > 0) {
+      high_idx += delta;
+    } else {
+      low_idx += delta;
     }
   }
-  if (data_end < 0) {
-    data_end += in.data_size();
+  int64_t data_size = (high_idx - low_idx) + 1;
+  if (data_size < 0) {
+    std::ostringstream msg;
+    msg << "[slice] Computed invalid data size: " << data_size << ".";
+    throw std::runtime_error(msg.str());
   }
-  size_t data_size = (data_end - data_offset);
   shared_buffer_slice(in, inp_strides, data_offset, data_size, out);
 }
 

mlx/backend/cpu/indexing.cpp

@@ -747,4 +747,108 @@ void ScatterAxis::eval_cpu(const std::vector<array>& inputs, array& out) {
   });
 }
 
+template <typename T>
+void masked_scatter_impl(const array& mask, const array& src, array& out) {
+  ContiguousIterator mask_it(mask);
+  ContiguousIterator src_it(src);
+  ContiguousIterator out_it(out);
+
+  const bool* mask_ptr = mask.data<bool>();
+  const T* src_ptr = src.data<T>();
+  T* dst_ptr = out.data<T>();
+
+  const size_t batch_count = mask.shape(0);
+  const size_t mask_batch_size = mask.size() / batch_count;
+  const size_t src_batch_size = src.size() / batch_count;
+
+  for (uint b = 0; b < batch_count; ++b) {
+    size_t src_consumed = 0;
+    src_it.seek(b * src_batch_size);
+
+    for (size_t i = 0; i < mask_batch_size; ++i) {
+      if (mask_ptr[mask_it.loc]) {
+        if (src_consumed >= src_batch_size) {
+          throw std::runtime_error(
+              "[MaskedScatter::eval_cpu] Source does not have enough elements for mask.");
+        }
+        dst_ptr[out_it.loc] = src_ptr[src_it.loc];
+        src_it.step();
+        ++src_consumed;
+      }
+      mask_it.step();
+      out_it.step();
+    }
+  }
+}
+
+void MaskedScatter::eval_cpu(const std::vector<array>& inputs, array& out) {
+  assert(inputs.size() == 3);
+
+  auto& dst = inputs[0];
+  auto& mask = inputs[1];
+  auto& src = inputs[2];
+
+  // Copy src into out (copy allocates memory for out)
+  auto ctype =
+      dst.flags().row_contiguous ? CopyType::Vector : CopyType::General;
+  copy_cpu(dst, out, ctype, stream());
+
+  if (mask.size() == 0) {
+    return;
+  }
+
+  auto& encoder = cpu::get_command_encoder(stream());
+  encoder.set_input_array(mask);
+  encoder.set_input_array(src);
+  encoder.set_output_array(out);
+  encoder.dispatch([mask = array::unsafe_weak_copy(mask),
+                    src = array::unsafe_weak_copy(src),
+                    out = array::unsafe_weak_copy(out)]() mutable {
+    switch (out.dtype()) {
+      case bool_:
+        masked_scatter_impl<bool>(mask, src, out);
+        break;
+      case uint8:
+        masked_scatter_impl<uint8_t>(mask, src, out);
+        break;
+      case uint16:
+        masked_scatter_impl<uint16_t>(mask, src, out);
+        break;
+      case uint32:
+        masked_scatter_impl<uint32_t>(mask, src, out);
+        break;
+      case uint64:
+        masked_scatter_impl<uint64_t>(mask, src, out);
+        break;
+      case int8:
+        masked_scatter_impl<int8_t>(mask, src, out);
+        break;
+      case int16:
+        masked_scatter_impl<int16_t>(mask, src, out);
+        break;
+      case int32:
+        masked_scatter_impl<int32_t>(mask, src, out);
+        break;
+      case int64:
+        masked_scatter_impl<int64_t>(mask, src, out);
+        break;
+      case float16:
+        masked_scatter_impl<float16_t>(mask, src, out);
+        break;
+      case float32:
+        masked_scatter_impl<float>(mask, src, out);
+        break;
+      case float64:
+        masked_scatter_impl<double>(mask, src, out);
+        break;
+      case bfloat16:
+        masked_scatter_impl<bfloat16_t>(mask, src, out);
+        break;
+      case complex64:
+        masked_scatter_impl<complex64_t>(mask, src, out);
+        break;
+    }
+  });
+}
+
 } // namespace mlx::core

mlx/backend/cuda/CMakeLists.txt

@@ -44,6 +44,7 @@ target_sources(
           ${CMAKE_CURRENT_SOURCE_DIR}/reduce/row_reduce.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/rms_norm.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/rope.cu
+          ${CMAKE_CURRENT_SOURCE_DIR}/scaled_dot_product_attention.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/scaled_dot_product_attention.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/scan.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/slicing.cpp
@@ -125,7 +126,11 @@ endif()
 # Compute capability >= 7.0 is required for synchronization between CPU/GPU with
 # managed memory.
 if(NOT DEFINED MLX_CUDA_ARCHITECTURES)
-  set(MLX_CUDA_ARCHITECTURES "native")
+  execute_process(
+    COMMAND bash detect_cuda_arch.sh
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+    OUTPUT_VARIABLE MLX_CUDA_ARCHITECTURES
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
 endif()
 message(STATUS "CUDA architectures: ${MLX_CUDA_ARCHITECTURES}")
 set_target_properties(mlx PROPERTIES CUDA_ARCHITECTURES
@@ -137,6 +142,7 @@ FetchContent_Declare(
   URL "https://github.com/NVIDIA/cccl/releases/download/v2.8.1/cccl-v2.8.1.zip")
 FetchContent_MakeAvailable(cccl)
 target_include_directories(mlx BEFORE PRIVATE "${cccl_SOURCE_DIR}/include")
+set_target_properties(mlx PROPERTIES CCCL_DIR "${cccl_SOURCE_DIR}/include")
 
 # Use fixed version of NVTX.
 FetchContent_Declare(
@@ -162,7 +168,7 @@ target_link_libraries(mlx PRIVATE CUDA::nvrtc CUDA::cuda_driver)
 FetchContent_Declare(
   cudnn
   GIT_REPOSITORY https://github.com/NVIDIA/cudnn-frontend.git
-  GIT_TAG v1.14.0
+  GIT_TAG v1.16.0
   GIT_SHALLOW TRUE
   EXCLUDE_FROM_ALL)
 set(CUDNN_FRONTEND_SKIP_JSON_LIB ON)

mlx/backend/cuda/allocator.cpp

@@ -92,7 +92,7 @@ CudaAllocator::CudaAllocator()
           [this](CudaBuffer* buf) { cuda_free(buf); }) {
   size_t free, total;
   CHECK_CUDA_ERROR(cudaMemGetInfo(&free, &total));
-  memory_limit_ = total * 0.95;
+  memory_limit_ = total * 0.9;
   max_pool_size_ = memory_limit_;
 
   int device_count = 0;
@@ -119,7 +119,8 @@ void copy_to_managed(CudaBuffer& buf) {
   buf.data = new_data;
 }
 
-Buffer CudaAllocator::malloc_impl(size_t size, cudaStream_t stream) {
+Buffer
+CudaAllocator::malloc_async(size_t size, int device, cudaStream_t stream) {
   if (size == 0) {
     return Buffer{new CudaBuffer{nullptr, 0, -1}};
   }
@@ -134,9 +135,8 @@ Buffer CudaAllocator::malloc_impl(size_t size, cudaStream_t stream) {
     size = page_size * ((size + page_size - 1) / page_size);
   }
 
-  int device = -1;
-  if (size > small_block_size && stream != nullptr) {
-    CHECK_CUDA_ERROR(cudaStreamGetDevice(stream, &device));
+  if (size <= small_block_size || stream == nullptr) {
+    device = -1;
   }
 
   CudaBuffer* buf = buffer_cache_.reuse_from_cache(size);
@@ -176,18 +176,14 @@ Buffer CudaAllocator::malloc_impl(size_t size, cudaStream_t stream) {
     buffer_cache_.release_cached_buffers(get_cache_memory() - max_pool_size_);
   }
   // Copy to managed here if the buffer is not on the right device
-  if (buf->device != device) {
+  if (buf->device >= 0 && buf->device != device) {
     copy_to_managed(*buf);
   }
   return Buffer{buf};
 }
 
-Buffer CudaAllocator::malloc_async(size_t size, cudaStream_t stream) {
-  return malloc_impl(size, stream);
-}
-
 Buffer CudaAllocator::malloc(size_t size) {
-  return malloc_impl(size, nullptr);
+  return malloc_async(size, -1, nullptr);
 }
 
 void CudaAllocator::free(Buffer buffer) {
@@ -223,9 +219,9 @@ void CudaAllocator::cuda_free(CudaBuffer* buf) {
     scalar_pool_.free(buf);
   } else {
     if (buf->device >= 0) {
-      cudaFreeAsync(buf->data, free_streams_[buf->device]);
+      CHECK_CUDA_ERROR(cudaFreeAsync(buf->data, free_streams_[buf->device]));
     } else {
-      cudaFree(buf->data);
+      CHECK_CUDA_ERROR(cudaFree(buf->data));
     }
     delete buf;
   }
@@ -277,8 +273,9 @@ CudaAllocator& allocator() {
   return *allocator_;
 }
 
-Buffer malloc_async(size_t size, cudaStream_t stream) {
-  auto buffer = allocator().malloc_async(size, stream);
+Buffer malloc_async(size_t size, CommandEncoder& encoder) {
+  auto buffer = allocator().malloc_async(
+      size, encoder.device().cuda_device(), encoder.stream());
   if (size && !buffer.ptr()) {
     std::ostringstream msg;
     msg << "[malloc_async] Unable to allocate " << size << " bytes.";

mlx/backend/cuda/allocator.h

@@ -13,6 +13,8 @@
 
 namespace mlx::core::cu {
 
+class CommandEncoder;
+
 using allocator::Buffer;
 
 // Stores cuda-managed unified memory.
@@ -48,7 +50,7 @@ class SmallSizePool {
 class CudaAllocator : public allocator::Allocator {
  public:
   Buffer malloc(size_t size) override;
-  Buffer malloc_async(size_t size, cudaStream_t stream);
+  Buffer malloc_async(size_t size, int device, cudaStream_t stream);
   void free(Buffer buffer) override;
   size_t size(Buffer buffer) const override;
 
@@ -62,7 +64,6 @@ class CudaAllocator : public allocator::Allocator {
   void clear_cache();
 
  private:
-  Buffer malloc_impl(size_t size, cudaStream_t stream);
   void cuda_free(CudaBuffer* buf);
 
   CudaAllocator();
@@ -80,6 +81,6 @@ class CudaAllocator : public allocator::Allocator {
 
 CudaAllocator& allocator();
 
-Buffer malloc_async(size_t size, cudaStream_t stream);
+Buffer malloc_async(size_t size, CommandEncoder& encoder);
 
 } // namespace mlx::core::cu

mlx/backend/cuda/arange.cu

@@ -42,7 +42,7 @@ void Arange::eval_gpu(const std::vector<array>& inputs, array& out) {
     return;
   }
   auto& encoder = cu::get_command_encoder(stream());
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   encoder.set_output_array(out);
 
   dispatch_int_float_types(out.dtype(), "Arange", [&](auto type_tag) {

mlx/backend/cuda/arg_reduce.cu

@@ -143,7 +143,7 @@ void ArgReduce::eval_gpu(const std::vector<array>& inputs, array& out) {
 
   auto& s = stream();
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
 
   // Prepare the shapes, strides and axis arguments.
   Shape shape = remove_index(in.shape(), axis_);

mlx/backend/cuda/binary/binary.cuh

@@ -367,9 +367,8 @@ void binary_op_gpu(
   auto bopt = get_binary_op_type(a, b);
   auto& encoder = cu::get_command_encoder(s);
 
-  set_binary_op_output_data(a, b, out, bopt, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
+  set_binary_op_output_data(
+      a, b, out, bopt, [&](auto n) { return cu::malloc_async(n, encoder); });
   binary_op_gpu_inplace<Op>(inputs, out, op, s);
 }
 

mlx/backend/cuda/binary_two.cu

@@ -246,12 +246,10 @@ void binary_two_op_gpu_inplace(
   auto& out_b = outputs[1];
   auto bopt = get_binary_op_type(a, b);
   auto& encoder = cu::get_command_encoder(s);
-  set_binary_op_output_data(a, b, out_a, bopt, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
-  set_binary_op_output_data(a, b, out_b, bopt, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
+  set_binary_op_output_data(
+      a, b, out_a, bopt, [&](auto n) { return cu::malloc_async(n, encoder); });
+  set_binary_op_output_data(
+      a, b, out_b, bopt, [&](auto n) { return cu::malloc_async(n, encoder); });
 
   if (out_a.size() == 0) {
     return;

mlx/backend/cuda/compiled.cpp

@@ -298,7 +298,7 @@ void Compiled::eval_gpu(
   // Put outputs.
   compiled_allocate_outputs(
       inputs, outputs, is_constant_, contiguous, [&](auto n) {
-        return cu::malloc_async(n, encoder.stream());
+        return cu::malloc_async(n, encoder);
       });
   for (auto& x : outputs) {
     args.append(x);

mlx/backend/cuda/conv.cpp

@@ -277,11 +277,12 @@ void Convolution::eval_gpu(const std::vector<array>& inputs, array& out_) {
   array in = inputs[0];
   array wt = inputs[1];
   array out = out_;
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   Dtype dtype = out.dtype();
 
   // Search cache.
-  ConvCacheKey cache_key{
+  BytesKey<ConvCacheKey> cache_key;
+  cache_key.pod = {
       encoder.device().cuda_device(),
       dtype_to_cudnn_type(dtype),
       vector_key(in.shape()),

mlx/backend/cuda/conv/gemm_conv.cu

@@ -86,7 +86,7 @@ array unfold_inputs_nd(
     int mat_N,
     ConvParams<NDIM>& params) {
   array unfolded({mat_M, mat_K}, in.dtype(), nullptr, {});
-  unfolded.set_data(cu::malloc_async(unfolded.nbytes(), encoder.stream()));
+  unfolded.set_data(cu::malloc_async(unfolded.nbytes(), encoder));
   encoder.add_temporary(unfolded);
 
   int filter_size = params.C;

mlx/backend/cuda/conv/gemm_grouped_conv.cu

@@ -89,7 +89,7 @@ array grouped_unfold_transpose_inputs_nd(
     int mat_N,
     ConvParams<NDIM>& params) {
   array unfolded({mat_M, mat_K * params.groups}, in.dtype(), nullptr, {});
-  unfolded.set_data(cu::malloc_async(unfolded.nbytes(), encoder.stream()));
+  unfolded.set_data(cu::malloc_async(unfolded.nbytes(), encoder));
   encoder.add_temporary(unfolded);
 
   int filter_size = params.C;

mlx/backend/cuda/copy.cu

@@ -7,9 +7,8 @@ namespace mlx::core {
 
 void copy_gpu(const array& in, array& out, CopyType ctype, const Stream& s) {
   auto& encoder = cu::get_command_encoder(s);
-  bool donated = set_copy_output_data(in, out, ctype, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
+  bool donated = set_copy_output_data(
+      in, out, ctype, [&](auto n) { return cu::malloc_async(n, encoder); });
   if (donated && in.dtype() == out.dtype()) {
     // If the output has the same type as the input then there is nothing to
     // copy, just use the buffer.
@@ -104,7 +103,7 @@ void fill_gpu(const array& in, array& out, const Stream& s) {
     return;
   }
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   encoder.set_input_array(in);
   encoder.set_output_array(out);
   copy_contiguous(encoder, CopyType::Scalar, in, out, 0, 0);
@@ -114,7 +113,7 @@ void reshape_gpu(const array& in, array& out, Stream s) {
   auto [copy_necessary, out_strides] = prepare_reshape(in, out);
   if (copy_necessary) {
     auto& encoder = cu::get_command_encoder(s);
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
     copy_gpu_inplace(
         in,
         out,

mlx/backend/cuda/cudnn_utils.cpp

@@ -135,9 +135,7 @@ bool prepare_cudnn_plan(
   void* workspace_ptr = nullptr;
   if (workspace_size > 0) {
     array workspace(
-        cu::malloc_async(workspace_size, encoder.stream()),
-        {workspace_size},
-        uint8);
+        cu::malloc_async(workspace_size, encoder), {workspace_size}, uint8);
     encoder.add_temporary(workspace);
     workspace_ptr = gpu_ptr<void>(workspace);
   }

mlx/backend/cuda/cudnn_utils.h

@@ -44,13 +44,13 @@ inline SmallVector<T> convert_vector(const Vec& vec) {
 // There are 2 differences from the const_param util from kernel_utils.cuh:
 // 1. The rest of array is filled with 0.
 // 2. This util can be used in .cpp files.
-template <typename T, template <typename U> class Vec>
-inline std::array<T, MAX_NDIM> vector_key(const Vec<T>& vec) {
-  if (vec.size() > MAX_NDIM) {
+template <int NDIM = MAX_NDIM, typename T, template <typename U> class Vec>
+inline std::array<T, NDIM> vector_key(const Vec<T>& vec) {
+  if (vec.size() > NDIM) {
     throw std::runtime_error(
-        fmt::format("ndim can not be larger than {}.", MAX_NDIM));
+        fmt::format("ndim can not be larger than {}.", NDIM));
   }
-  std::array<T, MAX_NDIM> result = {};
+  std::array<T, NDIM> result = {};
   std::copy_n(vec.begin(), vec.size(), result.begin());
   return result;
 }

mlx/backend/cuda/custom_kernel.cpp

@@ -57,7 +57,7 @@ std::string build_kernel(
     const std::vector<std::string>& output_names,
     const std::vector<Dtype>& output_dtypes,
     const std::vector<std::pair<std::string, TemplateArg>>& template_args,
-    const std::vector<CustomKernelShapeInfo>& shape_infos) {
+    const std::vector<std::tuple<bool, bool, bool>>& shape_infos) {
   std::string kernel_source;
   kernel_source.reserve(header.size() + source.size() + 8192);
   kernel_source += default_header;
@@ -81,17 +81,17 @@ std::string build_kernel(
     kernel_source += ",\n";
     // Add input shape, strides and ndim if present in the source
     if (arr.ndim() > 0) {
-      if (shape_infos[i].shape) {
+      if (std::get<0>(shape_infos[i])) {
         kernel_source += "    const __grid_constant__ Shape ";
         kernel_source += name;
         kernel_source += "_shape,\n";
       }
-      if (shape_infos[i].strides) {
+      if (std::get<1>(shape_infos[i])) {
         kernel_source += "    const __grid_constant__ Strides ";
         kernel_source += name;
         kernel_source += "_strides,\n";
       }
-      if (shape_infos[i].ndim) {
+      if (std::get<2>(shape_infos[i])) {
         kernel_source += "    const __grid_constant__ int ";
         kernel_source += name;
         kernel_source += "_ndim,\n";
@@ -154,12 +154,12 @@ CustomKernelFunction cuda_kernel(
         "[custom_kernel] Must specify at least one output.");
   }
 
-  std::vector<CustomKernelShapeInfo> shape_infos;
+  std::vector<std::tuple<bool, bool, bool>> shape_infos;
   for (auto& n : input_names) {
-    CustomKernelShapeInfo shape_info;
-    shape_info.shape = source.find(n + "_shape") != std::string::npos;
-    shape_info.strides = source.find(n + "_strides") != std::string::npos;
-    shape_info.ndim = source.find(n + "_ndim") != std::string::npos;
+    std::tuple<bool, bool, bool> shape_info;
+    std::get<0>(shape_info) = source.find(n + "_shape") != std::string::npos;
+    std::get<1>(shape_info) = source.find(n + "_strides") != std::string::npos;
+    std::get<2>(shape_info) = source.find(n + "_ndim") != std::string::npos;
     shape_infos.push_back(shape_info);
   }
 
@@ -254,8 +254,8 @@ std::vector<array> precompiled_cuda_kernel(
     std::optional<float> init_value,
     bool ensure_row_contiguous,
     StreamOrDevice s) {
-  std::vector<CustomKernelShapeInfo> shape_infos(
-      inputs.size(), CustomKernelShapeInfo{false, false, false});
+  std::vector<std::tuple<bool, bool, bool>> shape_infos(
+      inputs.size(), {false, false, false});
   return array::make_arrays(
       output_shapes,
       output_dtypes,
@@ -289,7 +289,7 @@ void CustomKernel::eval_gpu(
       copies.emplace_back(init_value_.value(), out.dtype());
       fill_gpu(copies.back(), out, s);
     } else {
-      out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+      out.set_data(cu::malloc_async(out.nbytes(), encoder));
     }
   }
 
@@ -327,13 +327,13 @@ void CustomKernel::eval_gpu(
     const array& in = checked_inputs[i];
     auto& shape_info = shape_infos_[i];
     args.append(in);
-    if (shape_info.shape) {
+    if (std::get<0>(shape_info)) {
       args.append_ndim(in.shape());
     }
-    if (shape_info.strides) {
+    if (std::get<1>(shape_info)) {
       args.append_ndim(in.strides());
     }
-    if (shape_info.ndim) {
+    if (std::get<2>(shape_info)) {
       args.append<int32_t>(in.ndim());
     }
   }

mlx/backend/cuda/detect_cuda_arch.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+arch=`__nvcc_device_query`
+case "$arch" in
+    "90")
+        echo "90a" ;;
+    "100")
+        echo "100a" ;;
+    "121")
+        echo "121a" ;;
+    *)
+        echo "native" ;;
+esac

mlx/backend/cuda/device.cpp

@@ -46,6 +46,7 @@ Device::Device(int device) : device_(device) {
         "Device {} does not support synchronization in managed memory.",
         device_));
   }
+
   // The cublasLt handle is used by matmul.
   make_current();
   CHECK_CUBLAS_ERROR(cublasLtCreate(&lt_));
@@ -189,12 +190,41 @@ void CommandEncoder::insert_graph_dependencies(std::vector<GraphNode> nodes) {
   }
 }
 
+// Can be tuned with MLX_MAX_OPS_PER_BUFFER, MLX_MAX_MB_PER_BUFFER
+std::pair<int, int> get_graph_limits(Device& d) {
+  auto cc =
+      d.compute_capability_major() * 100 + d.compute_capability_minor() * 10;
+  int ops = 20;
+  int mb = 100;
+  switch (cc) {
+    case 800: // A100
+      ops = 20;
+      mb = 400;
+      break;
+    case 900: // H100
+      ops = 30;
+      mb = 400;
+      break;
+    case 1000: // B200
+      ops = 50;
+      mb = 500;
+      break;
+    case 1210: // DGX Spark
+      ops = 20;
+      mb = 25;
+      break;
+  }
+  return {env::max_ops_per_buffer(ops), env::max_mb_per_buffer(mb)};
+}
+
 CommandEncoder::CommandEncoder(Device& d)
     : device_(d),
       stream_(d),
       graph_(d),
       worker_(d),
-      graph_cache_("MLX_CUDA_GRAPH_CACHE_SIZE", /* default_capacity */ 400) {}
+      graph_cache_("MLX_CUDA_GRAPH_CACHE_SIZE", /* default_capacity */ 400) {
+  std::tie(max_ops_per_graph_, max_mb_per_graph_) = get_graph_limits(d);
+}
 
 void CommandEncoder::add_completed_handler(std::function<void()> task) {
   worker_.add_task(std::move(task));
@@ -204,6 +234,7 @@ void CommandEncoder::set_input_array(const array& arr) {
   if (!use_cuda_graphs()) {
     return;
   }
+  bytes_in_graph_ += arr.data_size();
   auto id = reinterpret_cast<std::uintptr_t>(arr.buffer().ptr());
   active_deps_.push_back(id);
 }
@@ -301,8 +332,9 @@ void CommandEncoder::add_graph_node(cudaGraph_t child) {
   insert_graph_dependencies(GraphNode{node, 'G'});
 }
 
-int CommandEncoder::get_num_ops() {
-  return node_count_;
+bool CommandEncoder::needs_commit() {
+  return (node_count_ > max_ops_per_graph_) ||
+      ((bytes_in_graph_ >> 20) > max_mb_per_graph_);
 }
 
 void CommandEncoder::commit() {
@@ -365,10 +397,11 @@ void CommandEncoder::commit() {
   // Put completion handlers in a batch.
   worker_.commit(stream_);
   node_count_ = 0;
+  bytes_in_graph_ = 0;
 }
 
 void CommandEncoder::synchronize() {
-  cudaStreamSynchronize(stream_);
+  CHECK_CUDA_ERROR(cudaStreamSynchronize(stream_));
   auto p = std::make_shared<std::promise<void>>();
   std::future<void> f = p->get_future();
   add_completed_handler([p = std::move(p)]() { p->set_value(); });

mlx/backend/cuda/device.h

@@ -84,7 +84,7 @@ class CommandEncoder {
   }
 
   void add_completed_handler(std::function<void()> task);
-  int get_num_ops();
+  bool needs_commit();
   void commit();
 
   Device& device() {
@@ -131,6 +131,9 @@ class CommandEncoder {
   std::vector<std::uintptr_t> active_deps_;
   std::vector<std::uintptr_t> active_outputs_;
   std::unordered_map<std::uintptr_t, GraphNode> node_map_;
+  size_t bytes_in_graph_{0};
+  int max_ops_per_graph_;
+  int max_mb_per_graph_;
 };
 
 class Device {
@@ -166,6 +169,7 @@ class Device {
   int device_;
   int compute_capability_major_;
   int compute_capability_minor_;
+  std::string device_name_;
   cublasLtHandle_t lt_;
   cudnnHandle_t cudnn_;
   std::unordered_map<int, CommandEncoder> encoders_;

mlx/backend/cuda/distributed.cu

@@ -26,7 +26,7 @@ void AllReduce::eval_gpu(
       out.copy_shared_buffer(in);
       return {in, out};
     } else {
-      out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+      out.set_data(cu::malloc_async(out.nbytes(), encoder));
       return {in, out};
     }
   };
@@ -74,7 +74,7 @@ void AllGather::eval_gpu(
   };
 
   auto input = ensure_contiguous(inputs[0]);
-  outputs[0].set_data(cu::malloc_async(outputs[0].nbytes(), encoder.stream()));
+  outputs[0].set_data(cu::malloc_async(outputs[0].nbytes(), encoder));
 
   encoder.set_input_array(input);
   encoder.set_output_array(outputs[0]);
@@ -103,7 +103,7 @@ void ReduceScatter::eval_gpu(
   };
 
   auto input = ensure_contiguous(inputs[0]);
-  outputs[0].set_data(cu::malloc_async(outputs[0].nbytes(), encoder.stream()));
+  outputs[0].set_data(cu::malloc_async(outputs[0].nbytes(), encoder));
 
   encoder.set_input_array(input);
   encoder.set_output_array(outputs[0]);

mlx/backend/cuda/eval.cpp

@@ -11,9 +11,6 @@
 
 namespace mlx::core::gpu {
 
-// Can be tuned with MLX_MAX_OPS_PER_BUFFER
-constexpr int default_max_nodes_per_graph = 20;
-
 bool is_available() {
   return true;
 }
@@ -53,8 +50,7 @@ void eval(array& arr) {
     encoder.add_temporary(s);
   }
 
-  if (encoder.get_num_ops() >=
-      env::max_ops_per_buffer(default_max_nodes_per_graph)) {
+  if (encoder.needs_commit()) {
     scheduler::notify_new_task(stream);
     encoder.add_completed_handler(
         [stream]() { scheduler::notify_task_completion(stream); });

mlx/backend/cuda/gemms/cublas_gemm.cpp

@@ -370,7 +370,7 @@ void CublasGemm::execute(
     // Ensure workspace is 256-byte aligned
     int nbytes = cuda::ceil_div(heuristic_.workspaceSize, 256) * 256;
     array workspace(
-        cu::malloc_async(nbytes, encoder.stream()),
+        cu::malloc_async(nbytes, encoder),
         {static_cast<int>(heuristic_.workspaceSize)},
         int8);
     encoder.add_temporary(workspace);

mlx/backend/cuda/gemms/cublas_gemm_batched_12_9.cu

@@ -163,7 +163,7 @@ void CublasGemm::run_batched(
 
   // Launch kernel to set device offsets
   auto pointers = array(
-      cu::malloc_async(batch_count * sizeof(void*) * 3, encoder.stream()),
+      cu::malloc_async(batch_count * sizeof(void*) * 3, encoder),
       {batch_count * 3},
       uint64);
 
@@ -251,7 +251,7 @@ void CublasGemm::run_batched(
 
   // Launch kernel to set device offsets
   auto pointers = array(
-      cu::malloc_async(batch_count * sizeof(uint64_t) * 4, encoder.stream()),
+      cu::malloc_async(batch_count * sizeof(uint64_t) * 4, encoder),
       {batch_count * 4},
       uint64);
 

mlx/backend/cuda/indexing.cpp

@@ -61,7 +61,7 @@ void Gather::eval_gpu(const std::vector<array>& inputs, array& out) {
 
   auto& s = stream();
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   if (out.size() == 0) {
     return;
   }
@@ -241,7 +241,7 @@ void GatherAxis::eval_gpu(const std::vector<array>& inputs, array& out) {
 
   auto& s = stream();
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   if (out.size() == 0) {
     return;
   }

mlx/backend/cuda/jit_module.cpp

@@ -279,11 +279,14 @@ void compile(
   // Compile program.
   std::vector<const char*> args;
   bool use_sass = compiler_supports_device_sass(device);
+  auto cc = device.compute_capability_major();
+  std::string arch_tag = (cc == 90 || cc == 100 || cc == 121) ? "a" : "";
   std::string compute = fmt::format(
-      "--gpu-architecture={}_{}{}",
+      "--gpu-architecture={}_{}{}{}",
       use_sass ? "sm" : "compute",
-      device.compute_capability_major(),
-      device.compute_capability_minor());
+      cc,
+      device.compute_capability_minor(),
+      arch_tag);
   args.push_back(compute.c_str());
   std::string cccl_include = cccl_dir();
   if (!cccl_include.empty()) {

mlx/backend/cuda/layer_norm.cu

@@ -244,7 +244,7 @@ void LayerNorm::eval_gpu(
         out.copy_shared_buffer(x);
       } else {
         out.set_data(
-            cu::malloc_async(x.data_size() * x.itemsize(), encoder.stream()),
+            cu::malloc_async(x.data_size() * x.itemsize(), encoder),
             x.data_size(),
             x.strides(),
             x.flags());
@@ -335,7 +335,7 @@ void LayerNormVJP::eval_gpu(
     gx.copy_shared_buffer(g);
     g_in_gx = true;
   } else {
-    gx.set_data(cu::malloc_async(gx.nbytes(), encoder.stream()));
+    gx.set_data(cu::malloc_async(gx.nbytes(), encoder));
   }
   if (g_copied && !g_in_gx) {
     encoder.add_temporary(g);
@@ -355,7 +355,7 @@ void LayerNormVJP::eval_gpu(
       g_in_gw = true;
       gw_temp.copy_shared_buffer(g);
     } else {
-      gw_temp.set_data(cu::malloc_async(gw_temp.nbytes(), encoder.stream()));
+      gw_temp.set_data(cu::malloc_async(gw_temp.nbytes(), encoder));
       encoder.add_temporary(gw_temp);
     }
   }

mlx/backend/cuda/load.cpp

@@ -32,7 +32,7 @@ void Load::eval_gpu(const std::vector<array>& inputs, array& out) {
   auto& encoder = cu::get_command_encoder(stream());
   auto size = out.size();
   auto nbytes = size * out.itemsize();
-  out.set_data(cu::malloc_async(nbytes, encoder.stream()));
+  out.set_data(cu::malloc_async(nbytes, encoder));
   auto out_ptr = malloc(nbytes);
   reader_->read(static_cast<char*>(out_ptr), nbytes, offset_);
   if (swap_endianness_) {

mlx/backend/cuda/logsumexp.cu

@@ -115,7 +115,7 @@ void LogSumExp::eval_gpu(const std::vector<array>& inputs, array& out) {
 
   auto in = ensure_contiguous(inputs[0]);
   if (in.flags().row_contiguous) {
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
   } else {
     auto n = in.shape(-1);
     auto flags = in.flags();
@@ -130,7 +130,7 @@ void LogSumExp::eval_gpu(const std::vector<array>& inputs, array& out) {
     }
     flags.col_contiguous = col_contig;
     out.set_data(
-        cu::malloc_async(in.nbytes() / n, encoder.stream()),
+        cu::malloc_async(in.nbytes() / n, encoder),
         in.data_size() / n,
         std::move(strides),
         flags);

mlx/backend/cuda/lru_cache.h

@@ -135,12 +135,19 @@ class LRUCache {
 };
 
 // Turn a POD struct into a container key by doing bytes compare.
+//
+// Usage:
+//   BytesKey<MyKey> key;
+//   key.pod = { ... };
 template <typename T>
 struct BytesKey {
   T pod;
   static_assert(std::is_standard_layout_v<T>, "T is not POD");
 
-  BytesKey(T pod) : pod(std::move(pod)) {}
+  BytesKey() {
+    // Make sure the paddings between members are filled with 0.
+    memset(&pod, 0, sizeof(T));
+  }
 
   BytesKey(const BytesKey& other) {
     memcpy(&pod, &other.pod, sizeof(T));

mlx/backend/cuda/matmul.cpp

@@ -121,7 +121,7 @@ void Matmul::eval_gpu(const std::vector<array>& inputs, array& out) {
     return;
   }
 
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
 
   int M = a_pre.shape(-2);
   int N = b_pre.shape(-1);
@@ -163,7 +163,7 @@ void AddMM::eval_gpu(const std::vector<array>& inputs, array& out) {
 
   if (beta_ == 1 && a.dtype() != complex64 && c.strides(-1) == 1 &&
       c.data_size() == out.shape(-1)) {
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
     gemm_and_bias(
         encoder,
         M,
@@ -187,10 +187,10 @@ void AddMM::eval_gpu(const std::vector<array>& inputs, array& out) {
     auto sty = c.strides()[c.ndim() - 1];
     if (sty == 1 && stx == c.shape(-1)) {
       ldc = stx;
-      out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+      out.set_data(cu::malloc_async(out.nbytes(), encoder));
     } else if (sty == 1 && stx == 0) {
       ldc = 0;
-      out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+      out.set_data(cu::malloc_async(out.nbytes(), encoder));
     } else {
       // Copy C into out and set C to out
       ldc = c.shape(-1);

mlx/backend/cuda/primitives.cpp

@@ -37,6 +37,7 @@ NO_GPU(Inverse)
 NO_GPU(Cholesky)
 NO_GPU_MULTI(Eig)
 NO_GPU_MULTI(Eigh)
+NO_GPU(MaskedScatter)
 
 namespace distributed {
 NO_GPU_MULTI(Send)

mlx/backend/cuda/quantized/quantized.cpp

@@ -59,7 +59,7 @@ void fast::Quantize::eval_gpu(
     auto scales = ensure_row_contiguous(inputs[1], enc, s);
     auto& w = outputs[0];
 
-    w.set_data(cu::malloc_async(w.nbytes(), enc.stream()));
+    w.set_data(cu::malloc_async(w.nbytes(), enc));
 
     if (mode_ == QuantizationMode::Affine) {
       auto biases = ensure_row_contiguous(inputs[2], enc, s);
@@ -72,11 +72,11 @@ void fast::Quantize::eval_gpu(
     auto& wq = outputs[0];
     auto& scales = outputs[1];
 
-    wq.set_data(cu::malloc_async(wq.nbytes(), enc.stream()));
-    scales.set_data(cu::malloc_async(scales.nbytes(), enc.stream()));
+    wq.set_data(cu::malloc_async(wq.nbytes(), enc));
+    scales.set_data(cu::malloc_async(scales.nbytes(), enc));
     if (mode_ == QuantizationMode::Affine) {
       auto& biases = outputs[2];
-      biases.set_data(cu::malloc_async(biases.nbytes(), enc.stream()));
+      biases.set_data(cu::malloc_async(biases.nbytes(), enc));
       affine_quantize(w, wq, scales, biases, group_size_, bits_, enc, s);
     } else {
       fp_quantize(w, wq, scales, group_size_, bits_, enc, s);

mlx/backend/cuda/random.cu

@@ -139,30 +139,36 @@ void RandomBits::eval_gpu(const std::vector<array>& inputs, array& out) {
   // keys has shape (N1, ..., NK, 2)
   // out has shape (N1, ..., NK, M1, M2, ...)
   auto& keys = inputs[0];
-  uint32_t num_keys = keys.size() / 2;
+  size_t num_keys = keys.size() / 2;
 
-  uint32_t elems_per_key = out.size() / num_keys;
-  uint32_t bytes_per_key = out.itemsize() * elems_per_key;
+  size_t elems_per_key = out.size() / num_keys;
+  size_t bytes_per_key = out.itemsize() * elems_per_key;
   auto& s = stream();
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
   if (out.size() == 0) {
     return;
   }
 
-  uint32_t out_per_key = (bytes_per_key + 4 - 1) / 4;
-  uint32_t half_size = out_per_key / 2;
+  size_t out_per_key = (bytes_per_key + 4 - 1) / 4;
+  size_t half_size = out_per_key / 2;
+
   bool odd = out_per_key % 2;
+  if ((half_size + odd) >= UINT32_MAX || num_keys >= UINT32_MAX) {
+    throw std::runtime_error("[RandomBits::eval_gpu] Large size unsupported");
+  }
 
   encoder.set_input_array(keys);
   encoder.set_output_array(out);
-  dim3 grid_dims{num_keys, half_size + odd};
-  int64_t total = grid_dims.x * grid_dims.y;
-  int32_t threads_y = 1;
-  while ((total / threads_y) >= (1U << 31)) {
+  int64_t total = num_keys * (half_size + odd);
+  uint32_t threads_y = 1;
+  while ((total / threads_y) >= UINT_MAX) {
     threads_y *= 2;
   }
-  int32_t threads_x = cuda::ceil_div(total, threads_y);
+  uint32_t threads_x = cuda::ceil_div(total, threads_y);
+
+  dim3 grid_dims{
+      static_cast<uint32_t>(num_keys), static_cast<uint32_t>(half_size + odd)};
   auto [grid, block] = get_grid_and_block(threads_x, threads_y, 1);
   auto& stream = encoder.stream();
   if (keys.flags().row_contiguous) {

mlx/backend/cuda/reduce/all_reduce.cu

@@ -66,7 +66,7 @@ void all_reduce(
     Reduce::ReduceType reduce_type) {
   constexpr int N_READS = 8;
 
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
 
   auto get_args = [](size_t size, int N) {
     int threads = std::min(512UL, (size + N - 1) / N);
@@ -107,8 +107,7 @@ void all_reduce(
   encoder.set_input_array(in);
   if (blocks > 1) {
     array intermediate({blocks}, out.dtype(), nullptr, {});
-    intermediate.set_data(
-        cu::malloc_async(intermediate.nbytes(), encoder.stream()));
+    intermediate.set_data(cu::malloc_async(intermediate.nbytes(), encoder));
     encoder.add_temporary(intermediate);
     encoder.set_output_array(intermediate);
     dispatch_all_types(dt, [&](auto type_tag) {

mlx/backend/cuda/reduce/init_reduce.cu

@@ -28,7 +28,7 @@ void init_reduce(
     Reduce::ReduceType reduce_type) {
   // Allocate if needed
   if (out.data_shared_ptr() == nullptr) {
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
   }
 
   encoder.set_output_array(out);

mlx/backend/cuda/reduce/reduce_utils.cuh

@@ -96,7 +96,7 @@ inline void allocate_same_layout(
     const std::vector<int>& axes,
     cu::CommandEncoder& encoder) {
   if (in.flags().row_contiguous) {
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
     return;
   }
 
@@ -135,7 +135,7 @@ inline void allocate_same_layout(
   fl.col_contiguous = cc;
   fl.contiguous = true;
   out.set_data(
-      cu::malloc_async(out.nbytes(), encoder.stream()),
+      cu::malloc_async(out.nbytes(), encoder),
       data_size,
       final_strides,
       fl,

mlx/backend/cuda/rms_norm.cu

@@ -190,7 +190,7 @@ void RMSNorm::eval_gpu(
         out.copy_shared_buffer(x);
       } else {
         out.set_data(
-            cu::malloc_async(x.data_size() * x.itemsize(), encoder.stream()),
+            cu::malloc_async(x.data_size() * x.itemsize(), encoder),
             x.data_size(),
             x.strides(),
             x.flags());
@@ -274,7 +274,7 @@ void RMSNormVJP::eval_gpu(
     gx.copy_shared_buffer(g);
     g_in_gx = true;
   } else {
-    gx.set_data(cu::malloc_async(gx.nbytes(), encoder.stream()));
+    gx.set_data(cu::malloc_async(gx.nbytes(), encoder));
   }
   if (g_copied && !g_in_gx) {
     encoder.add_temporary(g);
@@ -292,7 +292,7 @@ void RMSNormVJP::eval_gpu(
     if (!g_in_gx && donate_g) {
       gw_temp.copy_shared_buffer(g);
     } else {
-      gw_temp.set_data(cu::malloc_async(gw_temp.nbytes(), encoder.stream()));
+      gw_temp.set_data(cu::malloc_async(gw_temp.nbytes(), encoder));
       encoder.add_temporary(gw_temp);
     }
   }

mlx/backend/cuda/rope.cu

@@ -292,14 +292,14 @@ void RoPE::eval_gpu(
       donated = true;
       out.copy_shared_buffer(in);
     } else {
-      out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+      out.set_data(cu::malloc_async(out.nbytes(), encoder));
     }
     strides[0] = mat_size;
     strides[1] = in.strides()[ndim - 2];
     strides[2] = in.strides()[ndim - 1];
   } else if (dispatch_ndim == 3) {
     // Handle non-contiguous 3D inputs
-    out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+    out.set_data(cu::malloc_async(out.nbytes(), encoder));
     strides[0] = in.strides()[ndim - 3];
     strides[1] = in.strides()[ndim - 2];
     strides[2] = in.strides()[ndim - 1];

mlx/backend/cuda/scaled_dot_product_attention.cpp

@@ -0,0 +1,537 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/cudnn_utils.h"
+#include "mlx/backend/cuda/device.h"
+#include "mlx/backend/cuda/lru_cache.h"
+#include "mlx/backend/gpu/copy.h"
+#include "mlx/fast_primitives.h"
+
+#include <nvtx3/nvtx3.hpp>
+
+namespace mlx::core {
+
+namespace fe = cudnn_frontend;
+
+namespace {
+
+#define CHECK_CUDNN_FE_ERROR(cmd)                                    \
+  do {                                                               \
+    auto error = cmd;                                                \
+    if (!error.is_good()) {                                          \
+      throw std::runtime_error(                                      \
+          fmt::format("{} failed: {}.", #cmd, error.get_message())); \
+    }                                                                \
+  } while (0)
+
+std::vector<int64_t> normalized_strides(const array& x) {
+  std::vector<int64_t> strides(x.strides().begin(), x.strides().end());
+  if (std::all_of(
+          strides.begin(), strides.end(), [](int64_t s) { return s == 0; })) {
+    strides.back() = 1;
+    return strides;
+  }
+  if (!x.flags().row_contiguous || x.ndim() < 2) {
+    return strides;
+  }
+  for (int i = x.ndim() - 2; i >= 0; --i) {
+    if (x.shape(i) == 1) {
+      strides[i] = x.shape(i + 1) * strides[i + 1];
+    }
+  }
+  return strides;
+}
+
+void set_tensor_attrs(
+    std::shared_ptr<fe::graph::Tensor_attributes>& tensor,
+    int64_t uid,
+    const array& x) {
+  tensor->set_uid(uid)
+      .set_dim({x.shape().begin(), x.shape().end()})
+      .set_stride(normalized_strides(x));
+}
+
+array prepare_sdpa_input(const array& x, Stream s) {
+  // SDPA kernel's requirements on inputs:
+  // 1. last dim's stride be 1;
+  // 2. pointer be aligned.
+  if (x.strides(-1) != 1 || get_alignment(x) < 16) {
+    array x_copy = contiguous_copy_gpu(x, s);
+    auto& encoder = cu::get_command_encoder(s);
+    encoder.add_temporary(x_copy);
+    return x_copy;
+  }
+  return x;
+}
+
+constexpr int QKV_NDIM = 4;
+
+struct SDPACacheKey {
+  int device_id;
+  cudnnDataType_t cudnn_dtype;
+  std::array<int, QKV_NDIM> q_shape;
+  std::array<int, QKV_NDIM> k_shape;
+  std::array<int, QKV_NDIM> v_shape;
+  std::array<int64_t, QKV_NDIM> q_strides;
+  std::array<int64_t, QKV_NDIM> k_strides;
+  std::array<int64_t, QKV_NDIM> v_strides;
+  bool do_causal;
+  bool output_logsumexp;
+};
+
+inline BytesKey<SDPACacheKey> build_sdpa_cache_key(
+    cu::CommandEncoder& encoder,
+    const array& q,
+    const array& k,
+    const array& v,
+    bool do_causal,
+    bool output_logsumexp = true) {
+  BytesKey<SDPACacheKey> cache_key;
+  cache_key.pod = {
+      encoder.device().cuda_device(),
+      dtype_to_cudnn_type(q.dtype()),
+      vector_key<QKV_NDIM>(q.shape()),
+      vector_key<QKV_NDIM>(k.shape()),
+      vector_key<QKV_NDIM>(v.shape()),
+      vector_key<QKV_NDIM>(q.strides()),
+      vector_key<QKV_NDIM>(k.strides()),
+      vector_key<QKV_NDIM>(v.strides()),
+      do_causal,
+      output_logsumexp,
+  };
+  return cache_key;
+}
+
+auto& sdpa_cache() {
+  static LRUBytesKeyCache<SDPACacheKey, fe::graph::Graph> cache(
+      "MLX_CUDA_SDPA_CACHE_SIZE", /* default_capacity */ 16);
+  return cache;
+}
+
+auto& sdpa_backward_cache() {
+  static LRUBytesKeyCache<SDPACacheKey, fe::graph::Graph> cache(
+      "MLX_CUDA_SDPA_BACKWARD_CACHE_SIZE", /* default_capacity */ 16);
+  return cache;
+}
+
+enum UIDS {
+  Q,
+  K,
+  V,
+  SCALE,
+  O,
+  STATS,
+  // Backward graph:
+  D_Q,
+  D_K,
+  D_V,
+  D_O,
+};
+
+fe::graph::Graph build_sdpa_graph(
+    cudnnHandle_t handle,
+    const array& q,
+    const array& k,
+    const array& v,
+    bool do_causal,
+    bool output_logsumexp,
+    const array& o,
+    const array& stats) {
+  auto dtype = fe::DataType_t::HALF;
+  if (q.dtype() == bfloat16) {
+    dtype = fe::DataType_t::BFLOAT16;
+  }
+
+  fe::graph::Graph graph;
+  graph.set_io_data_type(dtype)
+      .set_intermediate_data_type(fe::DataType_t::FLOAT)
+      .set_compute_data_type(fe::DataType_t::FLOAT);
+
+  auto q_ = graph.tensor(fe::graph::Tensor_attributes().set_name("Q"));
+  auto k_ = graph.tensor(fe::graph::Tensor_attributes().set_name("K"));
+  auto v_ = graph.tensor(fe::graph::Tensor_attributes().set_name("V"));
+  set_tensor_attrs(q_, Q, q);
+  set_tensor_attrs(k_, K, k);
+  set_tensor_attrs(v_, V, v);
+
+  auto scale = graph.tensor(fe::graph::Tensor_attributes()
+                                .set_name("Scale")
+                                .set_uid(SCALE)
+                                .set_dim({1, 1, 1, 1})
+                                .set_stride({1, 1, 1, 1})
+                                .set_is_pass_by_value(true)
+                                .set_data_type(fe::DataType_t::FLOAT));
+
+  auto options = fe::graph::SDPA_attributes()
+                     .set_name("sdpa_cudnn")
+                     .set_attn_scale(scale)
+                     .set_causal_mask(do_causal)
+                     .set_generate_stats(output_logsumexp);
+
+  auto [o_, stats_] = graph.sdpa(q_, k_, v_, options);
+  o_->set_output(true);
+  set_tensor_attrs(o_, O, o);
+  if (output_logsumexp) {
+    stats_->set_output(true).set_data_type(fe::DataType_t::FLOAT);
+    set_tensor_attrs(stats_, STATS, stats);
+  }
+
+  CHECK_CUDNN_FE_ERROR(graph.validate());
+  CHECK_CUDNN_FE_ERROR(graph.build_operation_graph(handle));
+  CHECK_CUDNN_FE_ERROR(graph.create_execution_plans({fe::HeurMode_t::A}));
+  graph.select_behavior_notes(
+      {fe::BehaviorNote_t::SUPPORTS_CUDA_GRAPH_NATIVE_API});
+  CHECK_CUDNN_FE_ERROR(graph.check_support(handle));
+  CHECK_CUDNN_FE_ERROR(graph.build_plans(handle));
+
+  return graph;
+}
+
+fe::graph::Graph build_sdpa_backward_graph(
+    cudnnHandle_t handle,
+    const array& q,
+    const array& k,
+    const array& v,
+    bool do_causal,
+    const array& o,
+    const array& d_o,
+    const array& stats,
+    array& d_q,
+    array& d_k,
+    array& d_v) {
+  auto dtype = fe::DataType_t::HALF;
+  if (q.dtype() == bfloat16) {
+    dtype = fe::DataType_t::BFLOAT16;
+  }
+
+  fe::graph::Graph graph;
+  graph.set_io_data_type(dtype)
+      .set_intermediate_data_type(fe::DataType_t::FLOAT)
+      .set_compute_data_type(fe::DataType_t::FLOAT);
+
+  auto q_ = graph.tensor(fe::graph::Tensor_attributes().set_name("Q"));
+  auto k_ = graph.tensor(fe::graph::Tensor_attributes().set_name("K"));
+  auto v_ = graph.tensor(fe::graph::Tensor_attributes().set_name("V"));
+  auto o_ = graph.tensor(fe::graph::Tensor_attributes().set_name("O"));
+  auto d_o_ = graph.tensor(fe::graph::Tensor_attributes().set_name("D_O"));
+  auto stats_ = graph.tensor(fe::graph::Tensor_attributes().set_name("STATS"));
+  set_tensor_attrs(q_, Q, q);
+  set_tensor_attrs(k_, K, k);
+  set_tensor_attrs(v_, V, v);
+  set_tensor_attrs(o_, O, o);
+  set_tensor_attrs(d_o_, D_O, d_o);
+  set_tensor_attrs(stats_, STATS, stats);
+  stats_->set_data_type(fe::DataType_t::FLOAT);
+
+  auto scale = graph.tensor(fe::graph::Tensor_attributes()
+                                .set_name("Scale")
+                                .set_uid(SCALE)
+                                .set_dim({1, 1, 1, 1})
+                                .set_stride({1, 1, 1, 1})
+                                .set_is_pass_by_value(true)
+                                .set_data_type(fe::DataType_t::FLOAT));
+
+  auto options = fe::graph::SDPA_backward_attributes()
+                     .set_name("sdpa_backward_cudnn")
+                     .set_attn_scale(scale)
+                     .set_causal_mask(do_causal);
+
+  auto [d_q_, d_k_, d_v_] =
+      graph.sdpa_backward(q_, k_, v_, o_, d_o_, stats_, options);
+  d_q_->set_output(true);
+  d_k_->set_output(true);
+  d_v_->set_output(true);
+  set_tensor_attrs(d_q_, D_Q, d_q);
+  set_tensor_attrs(d_k_, D_K, d_k);
+  set_tensor_attrs(d_v_, D_V, d_v);
+
+  CHECK_CUDNN_FE_ERROR(graph.validate());
+  CHECK_CUDNN_FE_ERROR(graph.build_operation_graph(handle));
+  CHECK_CUDNN_FE_ERROR(graph.create_execution_plans({fe::HeurMode_t::A}));
+  graph.select_behavior_notes(
+      {fe::BehaviorNote_t::SUPPORTS_CUDA_GRAPH_NATIVE_API});
+  CHECK_CUDNN_FE_ERROR(graph.check_support(handle));
+  CHECK_CUDNN_FE_ERROR(graph.build_plans(handle));
+
+  return graph;
+}
+
+void execute_graph(
+    cu::CommandEncoder& encoder,
+    cudnnHandle_t handle,
+    fe::graph::Graph& graph,
+    std::unordered_map<int64_t, void*>& variant_pack) {
+  int64_t workspace_size = 0;
+  CHECK_CUDNN_FE_ERROR(graph.get_workspace_size(workspace_size));
+  void* workspace_ptr = nullptr;
+  if (workspace_size > 0) {
+    array workspace(
+        cu::malloc_async(workspace_size, encoder),
+        {static_cast<int>(workspace_size)},
+        uint8);
+    encoder.add_temporary(workspace);
+    workspace_ptr = gpu_ptr<void>(workspace);
+  }
+
+  cudnnSetStream(handle, encoder.stream());
+
+  CudaGraph cuda_graph(encoder.device());
+  CHECK_CUDNN_FE_ERROR(graph.populate_cuda_graph(
+      handle, variant_pack, workspace_ptr, cuda_graph));
+  encoder.add_graph_node(cuda_graph);
+}
+
+} // namespace
+
+bool supports_sdpa_cudnn(
+    const array& q,
+    const array& k,
+    const array& v,
+    bool has_mask,
+    bool do_causal,
+    Stream s) {
+  static bool enabled = env::get_var("MLX_CUDA_USE_CUDNN_SPDA", 1);
+  if (!enabled) {
+    return false;
+  }
+
+  // cuDNN SDPA requires Ampere and later.
+  if (cu::device(s.device).compute_capability_major() < 8) {
+    return false;
+  }
+
+  if (has_mask) {
+    // TODO: Support array masks.
+    if (!do_causal) {
+      return false;
+    }
+    // FIXME: Causal mask generates wrong results when L_Q != L_K.
+    if (q.shape(2) != k.shape(2)) {
+      return false;
+    }
+  }
+
+  // Only use cuDNN for prefilling and training.
+  if (q.shape(2) != k.shape(2)) {
+    return false;
+  }
+
+  // D_qk and D_v must be a multiple of 8 with maximum value 128.
+  if ((q.shape(-1) % 8 != 0) || (q.shape(-1) > 128) || (v.shape(-1) % 8 != 0) ||
+      (v.shape(-1) > 128)) {
+    return false;
+  }
+
+  Dtype dtype = q.dtype();
+  return dtype == float16 || dtype == bfloat16;
+}
+
+void sdpa_cudnn(
+    const array& q,
+    const array& k,
+    const array& v,
+    float scale,
+    array& o,
+    array& stats,
+    bool do_causal,
+    bool output_logsumexp,
+    Stream s) {
+  auto& encoder = cu::get_command_encoder(s);
+  auto handle = encoder.device().cudnn_handle();
+
+  // TODO: Handle donation.
+  // TODO: Make O use same memory layout with Q.
+  o.set_data(cu::malloc_async(o.nbytes(), encoder));
+
+  encoder.set_input_array(q);
+  encoder.set_input_array(k);
+  encoder.set_input_array(v);
+  encoder.set_output_array(o);
+
+  if (output_logsumexp) {
+    stats.set_data(cu::malloc_async(stats.nbytes(), encoder));
+    encoder.set_output_array(stats);
+  }
+
+  // Search cache.
+  auto cache_key =
+      build_sdpa_cache_key(encoder, q, k, v, do_causal, output_logsumexp);
+  auto it = sdpa_cache().find(cache_key);
+  if (it == sdpa_cache().end()) {
+    auto graph = build_sdpa_graph(
+        handle, q, k, v, do_causal, output_logsumexp, o, stats);
+    it = sdpa_cache().emplace(cache_key, std::move(graph)).first;
+  }
+  auto& graph = it->second;
+
+  std::unordered_map<int64_t, void*> variant_pack{
+      {Q, const_cast<void*>(gpu_ptr<void>(q))},
+      {K, const_cast<void*>(gpu_ptr<void>(k))},
+      {V, const_cast<void*>(gpu_ptr<void>(v))},
+      {SCALE, &scale},
+      {O, gpu_ptr<void>(o)}};
+  if (output_logsumexp) {
+    variant_pack[STATS] = gpu_ptr<void>(stats);
+  }
+
+  execute_graph(encoder, handle, graph, variant_pack);
+}
+
+void sdpa_backward_cudnn(
+    const array& q,
+    const array& k,
+    const array& v,
+    float scale,
+    const array& o,
+    const array& stats,
+    bool do_causal,
+    const array& d_o,
+    array& d_q,
+    array& d_k,
+    array& d_v,
+    Stream s) {
+  auto& encoder = cu::get_command_encoder(s);
+  auto handle = encoder.device().cudnn_handle();
+
+  // TODO: Handle donation.
+  d_q.set_data(cu::malloc_async(d_q.nbytes(), encoder));
+  d_k.set_data(cu::malloc_async(d_k.nbytes(), encoder));
+  d_v.set_data(cu::malloc_async(d_v.nbytes(), encoder));
+
+  encoder.set_input_array(q);
+  encoder.set_input_array(k);
+  encoder.set_input_array(v);
+  encoder.set_input_array(o);
+  encoder.set_input_array(stats);
+  encoder.set_input_array(d_o);
+  encoder.set_output_array(d_q);
+  encoder.set_output_array(d_k);
+  encoder.set_output_array(d_v);
+
+  // Search cache.
+  auto cache_key = build_sdpa_cache_key(encoder, q, k, v, do_causal);
+  auto it = sdpa_backward_cache().find(cache_key);
+  if (it == sdpa_backward_cache().end()) {
+    auto graph = build_sdpa_backward_graph(
+        handle, q, k, v, do_causal, o, d_o, stats, d_q, d_k, d_v);
+    it = sdpa_backward_cache().emplace(cache_key, std::move(graph)).first;
+  }
+  auto& graph = it->second;
+
+  std::unordered_map<int64_t, void*> variant_pack{
+      {Q, const_cast<void*>(gpu_ptr<void>(q))},
+      {K, const_cast<void*>(gpu_ptr<void>(k))},
+      {V, const_cast<void*>(gpu_ptr<void>(v))},
+      {SCALE, &scale},
+      {O, const_cast<void*>(gpu_ptr<void>(o))},
+      {STATS, const_cast<void*>(gpu_ptr<void>(stats))},
+      {D_O, const_cast<void*>(gpu_ptr<void>(d_o))},
+      {D_Q, gpu_ptr<void>(d_q)},
+      {D_K, gpu_ptr<void>(d_k)},
+      {D_V, gpu_ptr<void>(d_v)}};
+
+  execute_graph(encoder, handle, graph, variant_pack);
+}
+
+// Defined in scaled_dot_product_attention.cu file.
+bool supports_sdpa_vector(
+    const array& q,
+    const array& k,
+    const array& v,
+    bool has_mask,
+    bool has_arr_mask,
+    bool do_causal,
+    bool output_logsumexp);
+void sdpa_vector(
+    const array& q,
+    const array& k,
+    const array& v,
+    float scale,
+    array& o,
+    bool do_causal,
+    const std::optional<array>& sinks,
+    Stream s);
+
+namespace fast {
+
+bool ScaledDotProductAttention::use_fallback(
+    const array& q,
+    const array& k,
+    const array& v,
+    bool has_mask,
+    bool has_arr_mask,
+    bool do_causal,
+    bool is_training,
+    bool output_logsumexp,
+    Stream s) {
+  if (s.device == Device::cpu) {
+    return true;
+  }
+
+  return !supports_sdpa_vector(
+             q, k, v, has_mask, has_arr_mask, do_causal, output_logsumexp) &&
+      !supports_sdpa_cudnn(q, k, v, has_mask, do_causal, s);
+}
+
+void ScaledDotProductAttention::eval_gpu(
+    const std::vector<array>& inputs,
+    std::vector<array>& outputs) {
+  nvtx3::scoped_range r("ScaledDotProductAttention::eval_gpu");
+
+  auto& s = stream();
+
+  array q = prepare_sdpa_input(inputs[0], s);
+  array k = prepare_sdpa_input(inputs[1], s);
+  array v = prepare_sdpa_input(inputs[2], s);
+  auto& out = outputs[0];
+  auto& stats = outputs[1];
+  bool has_mask = inputs.size() - has_sinks_ > 3;
+  bool has_arr_mask = has_mask && !do_causal_;
+
+  if (supports_sdpa_vector(
+          q, k, v, has_mask, has_arr_mask, do_causal_, output_logsumexp_)) {
+    if (has_sinks_) {
+      sdpa_vector(q, k, v, scale_, out, do_causal_, inputs.back(), s);
+    } else {
+      sdpa_vector(q, k, v, scale_, out, do_causal_, std::nullopt, s);
+    }
+  } else {
+    sdpa_cudnn(q, k, v, scale_, out, stats, do_causal_, output_logsumexp_, s);
+  }
+}
+
+bool ScaledDotProductAttentionVJP::use_fallback(const array& q, Stream s) {
+  // The frontend adds a padding mask when sequence length is not a multiple of
+  // tile size.
+  if (q.shape(2) % 128 != 0) {
+    return true;
+  }
+  return s.device == Device::cpu;
+}
+
+void ScaledDotProductAttentionVJP::eval_gpu(
+    const std::vector<array>& inputs,
+    std::vector<array>& outputs) {
+  nvtx3::scoped_range r("ScaledDotProductAttentionVJP::eval_gpu");
+
+  auto& s = stream();
+
+  assert(inputs.size() == 6);
+  array q = prepare_sdpa_input(inputs[0], s);
+  array k = prepare_sdpa_input(inputs[1], s);
+  array v = prepare_sdpa_input(inputs[2], s);
+  array o = prepare_sdpa_input(inputs[3], s);
+  array stats = prepare_sdpa_input(inputs[4], s);
+  array d_o = prepare_sdpa_input(inputs[5], s);
+
+  assert(outputs.size() == 3);
+  auto& d_q = outputs[0];
+  auto& d_k = outputs[1];
+  auto& d_v = outputs[2];
+
+  sdpa_backward_cudnn(
+      q, k, v, scale_, o, stats, do_causal_, d_o, d_q, d_k, d_v, s);
+}
+
+} // namespace fast
+
+} // namespace mlx::core

mlx/backend/cuda/scaled_dot_product_attention.cu

@@ -6,10 +6,6 @@
 #include "mlx/backend/cuda/kernel_utils.cuh"
 #include "mlx/backend/gpu/copy.h"
 #include "mlx/dtype_utils.h"
-#include "mlx/fast_primitives.h"
-#include "mlx/transforms_impl.h"
-
-#include <nvtx3/nvtx3.hpp>
 
 #include <cooperative_groups.h>
 #include <cooperative_groups/reduce.h>
@@ -565,10 +561,9 @@ void sdpa_vector_2pass_fallback(
   array sums(intermediate_shape, float32, nullptr, {});
   array maxs(std::move(intermediate_shape), float32, nullptr, {});
 
-  intermediate.set_data(
-      cu::malloc_async(intermediate.nbytes(), encoder.stream()));
-  sums.set_data(cu::malloc_async(sums.nbytes(), encoder.stream()));
-  maxs.set_data(cu::malloc_async(maxs.nbytes(), encoder.stream()));
+  intermediate.set_data(cu::malloc_async(intermediate.nbytes(), encoder));
+  sums.set_data(cu::malloc_async(sums.nbytes(), encoder));
+  maxs.set_data(cu::malloc_async(maxs.nbytes(), encoder));
 
   encoder.add_temporary(intermediate);
   encoder.add_temporary(sums);
@@ -663,21 +658,16 @@ void sdpa_vector_fallback(
 
 } // namespace
 
-namespace fast {
-
-bool ScaledDotProductAttention::use_fallback(
+bool supports_sdpa_vector(
     const array& q,
     const array& k,
     const array& v,
     bool has_mask,
     bool has_arr_mask,
     bool do_causal,
-    Stream s) {
-  if (detail::in_grad_tracing()) {
-    return true;
-  }
-  if (s.device == Device::cpu) {
-    return true;
+    bool output_logsumexp) {
+  if (output_logsumexp) {
+    return false;
   }
 
   const int value_head_dim = v.shape(-1);
@@ -691,29 +681,24 @@ bool ScaledDotProductAttention::use_fallback(
   const bool supported_vector_config =
       sdpa_supported_head_dim && query_sequence_length < 4;
 
-  const bool supported_config = supported_vector_config;
-
-  return has_arr_mask || !supported_config;
+  return supported_vector_config && !has_arr_mask;
 }
 
-void ScaledDotProductAttention::eval_gpu(
-    const std::vector<array>& inputs,
-    array& out) {
-  nvtx3::scoped_range r("ScaledDotProductAttention::eval_gpu");
-
-  auto& s = stream();
+void sdpa_vector(
+    const array& q_pre,
+    const array& k_pre,
+    const array& v_pre,
+    float scale,
+    array& o,
+    bool do_causal,
+    const std::optional<array>& sinks_pre,
+    Stream s) {
   auto& encoder = cu::get_command_encoder(s);
-
-  auto& q_pre = inputs[0];
-  auto& k_pre = inputs[1];
-  auto& v_pre = inputs[2];
-  auto& o = out;
-
   std::vector<array> copies;
 
   // Define some copy functions to ensure the layout of the inputs is as
   // expected.
-  copies.reserve(inputs.size());
+  copies.reserve(4);
   auto copy_unless = [&copies, &s](
                          auto predicate, const array& arr) -> const array& {
     if (!predicate(arr)) {
@@ -731,8 +716,8 @@ void ScaledDotProductAttention::eval_gpu(
   };
 
   std::optional<array> sinks = std::nullopt;
-  if (has_sinks_) {
-    sinks = copy_unless(is_matrix_contiguous, inputs.back());
+  if (sinks_pre) {
+    sinks = copy_unless(is_matrix_contiguous, sinks_pre.value());
   }
 
   // We are in vector mode ie single query
@@ -788,7 +773,7 @@ void ScaledDotProductAttention::eval_gpu(
       };
 
       o.set_data(
-          cu::malloc_async(o.nbytes(), encoder.stream()),
+          cu::malloc_async(o.nbytes(), encoder),
           o.size(),
           {str_oB, str_oH, str_oL, str_oD},
           flags);
@@ -798,8 +783,7 @@ void ScaledDotProductAttention::eval_gpu(
       encoder.add_temporary(cp);
     }
 
-    return sdpa_vector_fallback(
-        s, encoder, q, k, v, scale_, o, do_causal_, sinks);
+    sdpa_vector_fallback(s, encoder, q, k, v, scale, o, do_causal, sinks);
   }
 
   // Full attention mode should never reach here
@@ -808,6 +792,4 @@ void ScaledDotProductAttention::eval_gpu(
   }
 }
 
-} // namespace fast
-
 } // namespace mlx::core

mlx/backend/cuda/scan.cu

@@ -374,7 +374,7 @@ void Scan::eval_gpu(const std::vector<array>& inputs, array& out) {
       out.copy_shared_buffer(in);
     } else {
       out.set_data(
-          cu::malloc_async(in.data_size() * out.itemsize(), encoder.stream()),
+          cu::malloc_async(in.data_size() * out.itemsize(), encoder),
           in.data_size(),
           in.strides(),
           in.flags());

mlx/backend/cuda/slicing.cpp

@@ -24,7 +24,7 @@ void concatenate_gpu(
   std::partial_sum(sizes.cbegin(), sizes.cend(), sizes.begin());
 
   auto& encoder = cu::get_command_encoder(s);
-  out.set_data(cu::malloc_async(out.nbytes(), encoder.stream()));
+  out.set_data(cu::malloc_async(out.nbytes(), encoder));
 
   auto strides = out.strides();
   auto flags = out.flags();
@@ -89,7 +89,7 @@ array compute_dynamic_offset(
   if (donate) {
     offset.copy_shared_buffer(indices);
   } else {
-    offset.set_data(cu::malloc_async(offset.itemsize(), encoder.stream()));
+    offset.set_data(cu::malloc_async(offset.itemsize(), encoder));
   }
 
   encoder.add_temporary(offset);

mlx/backend/cuda/softmax.cu

@@ -118,7 +118,7 @@ void Softmax::eval_gpu(const std::vector<array>& inputs, array& out) {
         out.copy_shared_buffer(x);
       } else {
         out.set_data(
-            cu::malloc_async(x.data_size() * x.itemsize(), encoder.stream()),
+            cu::malloc_async(x.data_size() * x.itemsize(), encoder),
             x.data_size(),
             x.strides(),
             x.flags());

mlx/backend/cuda/sort.cu

@@ -49,14 +49,12 @@ void gpu_sort(const Stream& s, array in, array& out_, int axis, bool argsort) {
     array trans = swapaxes_in_eval(in, axis, last_dim);
     in = contiguous_copy_gpu(trans, s);
     encoder.add_temporary(in);
-    out = array(
-        cu::malloc_async(out.nbytes(), encoder.stream()),
-        in.shape(),
-        out.dtype());
+    out =
+        array(cu::malloc_async(out.nbytes(), encoder), in.shape(), out.dtype());
     encoder.add_temporary(out);
   } else {
     out.set_data(
-        cu::malloc_async(in.data_size() * out.itemsize(), encoder.stream()),
+        cu::malloc_async(in.data_size() * out.itemsize(), encoder),
         in.data_size(),
         in.strides(),
         in.flags());
@@ -74,17 +72,13 @@ void gpu_sort(const Stream& s, array in, array& out_, int axis, bool argsort) {
       if (argsort) {
         // Indices in the sorted dimension.
         array indices(
-            cu::malloc_async(out.nbytes(), encoder.stream()),
-            in.shape(),
-            out.dtype());
+            cu::malloc_async(out.nbytes(), encoder), in.shape(), out.dtype());
         encoder.add_temporary(indices);
 
         // In argsort though we don't need the result of sorted values, the
         // API requires us to provide an array to store it.
         array discard(
-            cu::malloc_async(in.nbytes(), encoder.stream()),
-            in.shape(),
-            in.dtype());
+            cu::malloc_async(in.nbytes(), encoder), in.shape(), in.dtype());
         encoder.add_temporary(discard);
 
         size_t size;
@@ -104,9 +98,7 @@ void gpu_sort(const Stream& s, array in, array& out_, int axis, bool argsort) {
             stream));
 
         array temp(
-            cu::malloc_async(size, encoder.stream()),
-            {static_cast<int>(size)},
-            uint8);
+            cu::malloc_async(size, encoder), {static_cast<int>(size)}, uint8);
         encoder.add_temporary(temp);
 
         // Start capturing after allocations
@@ -148,9 +140,7 @@ void gpu_sort(const Stream& s, array in, array& out_, int axis, bool argsort) {
             stream));
 
         array temp(
-            cu::malloc_async(size, encoder.stream()),
-            {static_cast<int>(size)},
-            uint8);
+            cu::malloc_async(size, encoder), {static_cast<int>(size)}, uint8);
         encoder.add_temporary(temp);
 
         // Start capturing after allocations

mlx/backend/cuda/ternary.cu

@@ -257,9 +257,8 @@ void ternary_op_gpu(
   auto& c = inputs[2];
   auto topt = get_ternary_op_type(a, b, c);
   auto& encoder = cu::get_command_encoder(s);
-  set_ternary_op_output_data(a, b, c, out, topt, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
+  set_ternary_op_output_data(
+      a, b, c, out, topt, [&](auto n) { return cu::malloc_async(n, encoder); });
   ternary_op_gpu_inplace<Op>(inputs, out, s);
 }
 

mlx/backend/cuda/unary/unary.cuh

@@ -208,9 +208,8 @@ void unary_op_gpu(
     const char* op,
     const Stream& s) {
   auto& encoder = cu::get_command_encoder(s);
-  set_unary_output_data(inputs[0], out, [&](auto n) {
-    return cu::malloc_async(n, encoder.stream());
-  });
+  set_unary_output_data(
+      inputs[0], out, [&](auto n) { return cu::malloc_async(n, encoder); });
   unary_op_gpu_inplace<Op>(inputs, out, op, s);
 }
 

mlx/backend/cuda/utils.cpp

@@ -60,7 +60,7 @@ const char* dtype_to_cuda_type(const Dtype& dtype) {
     case float64:
       return "double";
     case complex64:
-      return "complex64_t";
+      return "mlx::core::cu::complex64_t";
     default:
       return "unknown";
   }

mlx/backend/cuda/worker.cpp

@@ -44,7 +44,7 @@ void Worker::commit(cudaStream_t stream) {
   }
   signal_event_.record(stream);
   signal_event_.wait(signal_stream_);
-  cudaLaunchHostFunc(signal_stream_, signal, this);
+  CHECK_CUDA_ERROR(cudaLaunchHostFunc(signal_stream_, signal, this));
 }
 
 void Worker::thread_fn() {

mlx/backend/gpu/slicing.cpp

@@ -11,7 +11,7 @@ void slice_gpu(
     array& out,
     const Shape& start_indices,
     const Shape& strides,
-    const Stream& s) {
+    const Stream&) {
   slice(in, out, start_indices, strides);
 }
 

mlx/backend/metal/CMakeLists.txt

@@ -28,6 +28,7 @@ make_jit_source(binary_ops)
 make_jit_source(ternary_ops)
 make_jit_source(reduce_utils kernels/atomic.h kernels/reduction/ops.h)
 make_jit_source(indexing/scatter kernels/indexing/indexing.h)
+make_jit_source(indexing/masked_scatter)
 make_jit_source(indexing/gather kernels/indexing/indexing.h)
 make_jit_source(indexing/gather_front kernels/indexing/indexing.h)
 make_jit_source(indexing/gather_axis)

mlx/backend/metal/custom_kernel.cpp

@@ -32,7 +32,7 @@ std::string write_signature(
     const std::vector<Dtype>& output_dtypes,
     const std::vector<std::pair<std::string, TemplateArg>>& template_args,
     const std::vector<std::string>& attributes,
-    const std::vector<CustomKernelShapeInfo>& shape_infos,
+    const std::vector<std::tuple<bool, bool, bool>>& shape_infos,
     bool atomic_outputs) {
   std::string kernel_source;
   kernel_source.reserve(header.size() + source.size() + 16384);
@@ -88,19 +88,19 @@ std::string write_signature(
     index++;
     // Add input shape, strides and ndim if present in the source
     if (arr.ndim() > 0) {
-      if (shape_infos[i].shape) {
+      if (std::get<0>(shape_infos[i])) {
         kernel_source +=
             ("  const constant int* " + name + "_shape [[buffer(" +
              std::to_string(index) + ")]],\n");
         index++;
       }
-      if (shape_infos[i].strides) {
+      if (std::get<1>(shape_infos[i])) {
         kernel_source +=
             ("  const constant int64_t* " + name + "_strides [[buffer(" +
              std::to_string(index) + ")]],\n");
         index++;
       }
-      if (shape_infos[i].ndim) {
+      if (std::get<2>(shape_infos[i])) {
         kernel_source +=
             ("  const constant int& " + name + "_ndim [[buffer(" +
              std::to_string(index) + ")]],\n");
@@ -184,12 +184,12 @@ CustomKernelFunction metal_kernel(
     throw std::invalid_argument(
         "[metal_kernel] Must specify at least one output.");
   }
-  std::vector<CustomKernelShapeInfo> shape_infos;
+  std::vector<std::tuple<bool, bool, bool>> shape_infos;
   for (auto& n : input_names) {
-    CustomKernelShapeInfo shape_info;
-    shape_info.shape = source.find(n + "_shape") != std::string::npos;
-    shape_info.strides = source.find(n + "_strides") != std::string::npos;
-    shape_info.ndim = source.find(n + "_ndim") != std::string::npos;
+    std::tuple<bool, bool, bool> shape_info;
+    std::get<0>(shape_info) = source.find(n + "_shape") != std::string::npos;
+    std::get<1>(shape_info) = source.find(n + "_strides") != std::string::npos;
+    std::get<2>(shape_info) = source.find(n + "_ndim") != std::string::npos;
     shape_infos.push_back(shape_info);
   }
   const std::vector<std::pair<std::string, std::string>> metal_attributes = {
@@ -388,15 +388,15 @@ void CustomKernel::eval_gpu(
     index++;
     if (in.ndim() > 0) {
       int ndim = in.ndim();
-      if (shape_info.shape) {
+      if (std::get<0>(shape_info)) {
         compute_encoder.set_vector_bytes(in.shape(), ndim, index);
         index++;
       }
-      if (shape_info.strides) {
+      if (std::get<1>(shape_info)) {
         compute_encoder.set_vector_bytes(in.strides(), ndim, index);
         index++;
       }
-      if (shape_info.ndim) {
+      if (std::get<2>(shape_info)) {
         compute_encoder.set_bytes(ndim, index);
         index++;
       }

mlx/backend/metal/device.cpp

@@ -382,11 +382,8 @@ MTL::CommandQueue* Device::get_queue(Stream stream) {
 
 bool Device::command_buffer_needs_commit(int index) {
   auto& stream = get_stream_(index);
-  if (stream.buffer_ops > max_ops_per_buffer_ ||
-      (stream.buffer_sizes >> 20) > max_mb_per_buffer_) {
-    return true;
-  }
-  return false;
+  return (stream.buffer_ops > max_ops_per_buffer_) ||
+      ((stream.buffer_sizes >> 20) > max_mb_per_buffer_);
 }
 
 MTL::CommandBuffer* Device::get_command_buffer(int index) {

mlx/backend/metal/device.h

@@ -265,4 +265,19 @@ Device& device(mlx::core::Device);
 
 std::unique_ptr<void, std::function<void(void*)>> new_scoped_memory_pool();
 
+inline bool is_nax_available() {
+  auto _check_nax = []() {
+    bool can_use_nax = false;
+    if (__builtin_available(
+            macOS 26.2, iOS 26.2, tvOS 26.2, visionOS 26.2, *)) {
+      can_use_nax = true;
+    }
+    can_use_nax &=
+        metal::device(mlx::core::Device::gpu).get_architecture_gen() >= 17;
+    return can_use_nax;
+  };
+  static bool is_nax_available_ = _check_nax();
+  return is_nax_available_;
+}
+
 } // namespace mlx::core::metal

mlx/backend/metal/indexing.cpp

@@ -1,4 +1,5 @@
 // Copyright © 2023-2024 Apple Inc.
+
 #include <fmt/format.h>
 
 #include "mlx/backend/common/compiled.h"
@@ -8,7 +9,9 @@
 #include "mlx/backend/metal/jit/includes.h"
 #include "mlx/backend/metal/jit/indexing.h"
 #include "mlx/backend/metal/kernels.h"
+#include "mlx/backend/metal/scan.h"
 #include "mlx/backend/metal/utils.h"
+#include "mlx/dtype.h"
 #include "mlx/primitives.h"
 #include "mlx/utils.h"
 
@@ -641,4 +644,84 @@ void ScatterAxis::eval_gpu(const std::vector<array>& inputs, array& out) {
   compute_encoder.dispatch_threads(grid_dims, group_dims);
 }
 
+void MaskedScatter::eval_gpu(const std::vector<array>& inputs, array& out) {
+  const array& dst = inputs[0];
+  const array& mask = inputs[1];
+  const array& src = inputs[2];
+
+  auto& s = stream();
+  auto& d = metal::device(s.device);
+
+  const size_t total = mask.size();
+  const CopyType ct = (total == 1)
+      ? CopyType::Scalar
+      : (dst.flags().row_contiguous ? CopyType::Vector : CopyType::General);
+  copy_gpu(dst, out, ct, s);
+  if (total == 0) {
+    return;
+  }
+
+  array mask_flat = flatten_in_eval(mask, 1, -1, s);
+  if (mask_flat.data<void>() != mask.data<void>()) {
+    d.add_temporary(mask_flat, s.index);
+  }
+
+  if (!mask_flat.flags().row_contiguous) {
+    mask_flat = contiguous_copy_gpu(mask_flat, s);
+    d.add_temporary(mask_flat, s.index);
+  }
+
+  // Prefix (exclusive) of mask → scatter_offsets
+  array scatter_offsets(mask_flat.shape(), uint32, nullptr, {});
+  scatter_offsets.set_data(allocator::malloc(scatter_offsets.nbytes()));
+  d.add_temporary(scatter_offsets, s.index);
+
+  scan_gpu_inplace(
+      mask_flat,
+      scatter_offsets,
+      Scan::Sum,
+      /*axis=*/1,
+      /*reverse=*/false,
+      /*inclusive=*/false,
+      s);
+
+  // Kernel selection/build
+  static constexpr std::string_view kBaseName = "masked_assign";
+  const std::string dtype_tag = type_to_name(out.dtype());
+  const std::string value_type = get_type_string(out.dtype());
+  const std::string contiguous =
+      (src.flags().row_contiguous) ? "true" : "false";
+  const std::string kernel_name =
+      fmt::format("{}_{}_{}", kBaseName, dtype_tag, contiguous);
+
+  auto lib = d.get_library(kernel_name, [&]() {
+    std::string source = metal::utils();
+    source += metal::masked_scatter();
+    source += fmt::format(
+        std::string(masked_assign_kernel), kernel_name, value_type, contiguous);
+    return source;
+  });
+  auto kernel = d.get_kernel(kernel_name, lib);
+
+  // Binding
+  int bind_idx = 0;
+  const int ndim = static_cast<int>(src.ndim());
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  compute_encoder.set_compute_pipeline_state(kernel);
+  compute_encoder.set_input_array(mask_flat, bind_idx++);
+  compute_encoder.set_input_array(scatter_offsets, bind_idx++);
+  compute_encoder.set_input_array(src, bind_idx++);
+  compute_encoder.set_output_array(out, bind_idx++);
+  compute_encoder.set_vector_bytes(src.shape(), bind_idx++);
+  compute_encoder.set_vector_bytes(src.strides(), bind_idx++);
+  compute_encoder.set_bytes(ndim, bind_idx++);
+  compute_encoder.set_bytes(src.size() / src.shape(0), bind_idx++);
+  compute_encoder.set_bytes(mask_flat.size() / mask.shape(0), bind_idx++);
+
+  // Dispatch
+  auto group_dims = get_block_dims(total, 1, 1);
+  MTL::Size grid_dims(total, 1, 1);
+  compute_encoder.dispatch_threads(grid_dims, group_dims);
+}
+
 } // namespace mlx::core

mlx/backend/metal/jit/includes.h

@@ -11,6 +11,7 @@ const char* ternary_ops();
 const char* reduce_utils();
 const char* gather();
 const char* scatter();
+const char* masked_scatter();
 
 const char* arange();
 const char* unary();

mlx/backend/metal/jit/indexing.h

@@ -70,3 +70,7 @@ constexpr std::string_view scatter_kernels = R"(
       gid);
 }}
 )";
+
+constexpr std::string_view masked_assign_kernel = R"(
+template [[host_name("{0}")]] [[kernel]] decltype(masked_assign_impl<{1}, {2}>) masked_assign_impl<{1}, {2}>;
+)";

mlx/backend/metal/kernels/CMakeLists.txt

@@ -9,7 +9,14 @@ set(BASE_HEADERS
     utils.h)
 
 function(build_kernel_base TARGET SRCFILE DEPS)
-  set(METAL_FLAGS -Wall -Wextra -fno-fast-math -Wno-c++17-extensions)
+  set(METAL_FLAGS
+      -x
+      metal
+      -Wall
+      -Wextra
+      -fno-fast-math
+      -Wno-c++17-extensions
+      -Wno-c++20-extensions)
   if(MLX_METAL_DEBUG)
     set(METAL_FLAGS ${METAL_FLAGS} -gline-tables-only -frecord-sources)
   endif()
@@ -120,6 +127,30 @@ if(NOT MLX_METAL_JIT)
   build_kernel(gemv_masked steel/utils.h)
 endif()
 
+if((MLX_METAL_VERSION GREATER_EQUAL 400) AND (MACOS_SDK_VERSION GREATER_EQUAL
+                                              26.2))
+  set(STEEL_NAX_HEADERS
+      steel/defines.h
+      steel/utils.h
+      steel/gemm/transforms.h
+      steel/gemm/nax.h
+      steel/gemm/gemm_nax.h
+      steel/utils/type_traits.h
+      steel/utils/integral_constant.h)
+
+  build_kernel(steel/gemm/kernels/steel_gemm_fused_nax ${STEEL_NAX_HEADERS})
+  build_kernel(steel/gemm/kernels/steel_gemm_gather_nax ${STEEL_NAX_HEADERS})
+
+  build_kernel(quantized_nax quantized_nax.h ${STEEL_NAX_HEADERS})
+  build_kernel(fp_quantized_nax fp_quantized_nax.h ${STEEL_NAX_HEADERS})
+
+  set(STEEL_NAX_ATTN_HEADERS
+      steel/defines.h steel/utils.h steel/attn/nax.h steel/utils/type_traits.h
+      steel/utils/integral_constant.h)
+
+  build_kernel(steel/attn/kernels/steel_attention_nax ${STEEL_NAX_ATTN_HEADERS})
+endif()
+
 add_custom_command(
   OUTPUT ${MLX_METAL_PATH}/mlx.metallib
   COMMAND xcrun -sdk macosx metallib ${KERNEL_AIR} -o

mlx/backend/metal/kernels/fp_quantized_nax.metal

@@ -0,0 +1,74 @@
+// Copyright © 2025 Apple Inc.
+
+// clang-format off
+#include "mlx/backend/metal/kernels/utils.h"
+#include "mlx/backend/metal/kernels/steel/gemm/gemm.h"
+#include "mlx/backend/metal/kernels/quantized_utils.h"
+#include "mlx/backend/metal/kernels/steel/gemm/nax.h"
+#include "mlx/backend/metal/kernels/fp_quantized_nax.h"
+
+
+#define instantiate_quantized_batched(mode, name, type, bm, bn, bk, wm, wn, batched) \
+  instantiate_kernel( \
+      #mode "_" #name "_" #type "_gs_32_b_4_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_batch_" #batched, \
+      fp_ ## name,  \
+      type,         \
+      32,           \
+      4,            \
+      batched)
+
+#define instantiate_quantized_aligned(mode, name, type, bm, bn, bk, wm, wn, aligned) \
+  instantiate_kernel( \
+      #mode "_" #name "_" #type "_gs_32_b_4_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_alN_" #aligned, \
+      fp_ ## name, \
+      type,        \
+      32,          \
+      4,           \
+      aligned)
+
+#define instantiate_quantized_aligned_batched(mode, name, type, bm, bn, bk, wm, wn, aligned, batched) \
+  instantiate_kernel( \
+      #mode "_" #name "_" #type "_gs_32_b_4_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_alN_" #aligned "_batch_" #batched, \
+      fp_ ## name,    \
+      type,    \
+      32,      \
+      4,       \
+      aligned, \
+      batched)
+
+#define instantiate_gather_qmm_rhs(func, name, type, bm, bn, bk, wm, wn, transpose) \
+  instantiate_kernel( \
+      #name "_" #type "_gs_32_b_4_bm_" #bm "_bn_" #bn "_bk_" #bk "_wm_" #wm "_wn_" #wn, \
+      func,    \
+      type,    \
+      32,      \
+      4,       \
+      bm,      \
+      bn,      \
+      bk,      \
+      wm,      \
+      wn,      \
+      transpose)
+
+
+#define instantiate_quantized_all_aligned(type) \
+  instantiate_quantized_aligned(mxfp4, gather_qmm_t_nax, type, 64, 64, 64, 2, 2, true)      \
+  instantiate_quantized_aligned(mxfp4, gather_qmm_t_nax, type, 64, 64, 64, 2, 2, false)     \
+  instantiate_quantized_aligned_batched(mxfp4, qmm_t_nax, type, 64, 64, 64, 2, 2, true, 1)  \
+  instantiate_quantized_aligned_batched(mxfp4, qmm_t_nax, type, 64, 64, 64, 2, 2, true, 0)  \
+  instantiate_quantized_aligned_batched(mxfp4, qmm_t_nax, type, 64, 64, 64, 2, 2, false, 1) \
+  instantiate_quantized_aligned_batched(mxfp4, qmm_t_nax, type, 64, 64, 64, 2, 2, false, 0)
+
+
+#define instantiate_quantized_all_rhs(type) \
+  instantiate_gather_qmm_rhs(fp_gather_qmm_rhs_nax, mxfp4_gather_qmm_rhs_nax_nt, type, 64, 64, 64, 2, 2, true) \
+  instantiate_gather_qmm_rhs(fp_gather_qmm_rhs_nax, mxfp4_gather_qmm_rhs_nax_nn, type, 64, 64, 64, 2, 2, false) 
+
+#define instantiate_quantized_types(type) \
+  instantiate_quantized_all_aligned(type) \
+  instantiate_quantized_all_rhs(type)
+
+instantiate_quantized_types(float)
+instantiate_quantized_types(bfloat16_t)
+instantiate_quantized_types(float16_t)
+    // clang-format on

mlx/backend/metal/kernels/indexing/masked_scatter.h

@@ -0,0 +1,38 @@
+// Copyright © 2025 Apple Inc.
+
+#pragma once
+
+template <typename T, bool src_contiguous>
+[[kernel]] void masked_assign_impl(
+    const device bool* mask [[buffer(0)]],
+    const device uint* scatter_offsets [[buffer(1)]],
+    const device T* src [[buffer(2)]],
+    device T* out [[buffer(3)]],
+    const constant int* src_shapes [[buffer(4)]],
+    const constant int64_t* src_strides [[buffer(5)]],
+    const constant int& src_ndim [[buffer(6)]],
+    const constant int64_t& src_batch_size [[buffer(7)]],
+    const constant int64_t& mask_batch_size [[buffer(8)]],
+    uint idx [[thread_position_in_grid]]) {
+  const bool mask_value = mask[idx];
+  if (!mask_value) {
+    return;
+  }
+
+  const uint src_index = scatter_offsets[idx];
+  if (src_index >= src_batch_size) {
+    return;
+  }
+
+  const uint batch_idx = idx / mask_batch_size;
+
+  if (src_contiguous) {
+    out[idx] = src[batch_idx * src_batch_size + src_index];
+  } else {
+    out[idx] = src[elem_to_loc<uint>(
+        batch_idx * src_batch_size + src_index,
+        src_shapes,
+        src_strides,
+        src_ndim)];
+  }
+}

mlx/backend/metal/kernels/quantized_nax.metal

@@ -0,0 +1,106 @@
+// Copyright © 2023-2024 Apple Inc.
+
+// clang-format off
+#include "mlx/backend/metal/kernels/utils.h"
+#include "mlx/backend/metal/kernels/steel/gemm/gemm.h"
+#include "mlx/backend/metal/kernels/steel/gemm/nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/loader.h"
+#include "mlx/backend/metal/kernels/quantized_nax.h"
+
+#define instantiate_quantized(name, type, group_size, bits, bm, bn, bk, wm, wn)  \
+  instantiate_kernel(                                                    \
+      #name "_" #type "_gs_" #group_size "_b_" #bits,                    \
+      name,                                                              \
+      type,                                                              \
+      group_size,                                                        \
+      bits, bm, bk, bn, wm, wn)
+
+#define instantiate_quantized_batched(name, type, group_size, bits, bm, bn, bk, wm, wn, batched)     \
+  instantiate_kernel(                                                    \
+      #name "_" #type "_gs_" #group_size "_b_" #bits "_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_batch_" #batched, \
+      name,                                                              \
+      type,                                                              \
+      group_size,                                                        \
+      bits,                                                              \
+      batched, bm, bk, bn, wm, wn)
+
+#define instantiate_quantized_aligned(name, type, group_size, bits, bm, bn, bk, wm, wn, aligned)     \
+  instantiate_kernel(                                                                     \
+      #name "_" #type "_gs_" #group_size "_b_" #bits "_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_alN_" #aligned, \
+      name,                                                                  \
+      type,                                                                  \
+      group_size,                                                            \
+      bits,                                                                  \
+      aligned, bm, bk, bn, wm, wn)
+
+#define instantiate_quantized_aligned_batched(name, type, group_size, bits, bm, bn, bk, wm, wn, aligned, batched)     \
+  instantiate_kernel(                                                                     \
+      #name "_" #type "_gs_" #group_size "_b_" #bits "_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn "_alN_" #aligned "_batch_" #batched, \
+      name,                                                                  \
+      type,                                                                  \
+      group_size,                                                            \
+      bits,                                                                  \
+      aligned,                                                               \
+      batched, bm, bk, bn, wm, wn)
+
+#define instantiate_gather_qmm_rhs(func, name, type, group_size, bits, bm, bn, bk, wm, wn, transpose)        \
+  instantiate_kernel(                                                                                        \
+      #name "_" #type "_gs_" #group_size "_b_" #bits "_bm_" #bm "_bn_" #bn "_bk_" #bk "_wm_" #wm "_wn_" #wn, \
+      func,                                                         \
+      type,                                                         \
+      group_size,                                                   \
+      bits,                                                         \
+      bm,                                                           \
+      bn,                                                           \
+      bk,                                                           \
+      wm,                                                           \
+      wn,                                                           \
+      transpose)
+
+#define instantiate_quantized_batched_wrap(name, type, group_size, bits) \
+  instantiate_quantized_batched(name, type, group_size, bits, 64, 64, 64, 2, 2, 1)      \
+  instantiate_quantized_batched(name, type, group_size, bits, 64, 64, 64, 2, 2, 0)
+
+#define instantiate_quantized_all_batched(type, group_size, bits) \
+  instantiate_quantized_batched_wrap(affine_qmm_n_nax, type, group_size, bits)
+
+
+#define instantiate_quantized_all_single(type, group_size, bits) \
+  instantiate_quantized(affine_gather_qmm_n_nax, type, group_size, bits, 64, 64, 64, 2, 2)
+
+#define instantiate_quantized_all_aligned(type, group_size, bits)   \
+  instantiate_quantized_aligned(affine_gather_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, true) \
+  instantiate_quantized_aligned(affine_gather_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, false) \
+  instantiate_quantized_aligned_batched(affine_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, true, 1) \
+  instantiate_quantized_aligned_batched(affine_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, true, 0) \
+  instantiate_quantized_aligned_batched(affine_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, false, 1) \
+  instantiate_quantized_aligned_batched(affine_qmm_t_nax, type, group_size, bits, 64, 64, 64, 2, 2, false, 0)
+
+#define instantiate_quantized_all_rhs(type, group_size, bits) \
+  instantiate_gather_qmm_rhs(affine_gather_qmm_rhs_nax, affine_gather_qmm_rhs_nax_nt, type, group_size, bits, 64, 64, 64, 2, 2, true) \
+  instantiate_gather_qmm_rhs(affine_gather_qmm_rhs_nax, affine_gather_qmm_rhs_nax_nn, type, group_size, bits, 64, 64, 64, 2, 2, false)
+
+#define instantiate_quantized_funcs(type, group_size, bits) \
+  instantiate_quantized_all_batched(type, group_size, bits) \
+  instantiate_quantized_all_aligned(type, group_size, bits) \
+  instantiate_quantized_all_rhs(type, group_size, bits)
+
+#define instantiate_quantized_types(group_size, bits)       \
+  instantiate_quantized_funcs(float, group_size, bits)      \
+  instantiate_quantized_funcs(float16_t, group_size, bits)  \
+  instantiate_quantized_funcs(bfloat16_t, group_size, bits)  
+
+#define instantiate_quantized_groups(bits) \
+  instantiate_quantized_types(128, bits)   \
+  instantiate_quantized_types(64, bits)    \
+  instantiate_quantized_types(32, bits)
+
+#define instantiate_quantized_all() \
+  instantiate_quantized_groups(2) \
+  instantiate_quantized_groups(3) \
+  instantiate_quantized_groups(4) \
+  instantiate_quantized_groups(5) \
+  instantiate_quantized_groups(6) \
+  instantiate_quantized_groups(8)
+
+instantiate_quantized_all() // clang-format on

mlx/backend/metal/kernels/scan.metal

@@ -51,6 +51,7 @@ using namespace metal;
   instantiate_strided_scan(reverse_exclusive_##name, itype, otype, op, false, true, nreads)
 
 instantiate_scan_helper(sum_bool__int32,         bool,        int32_t,     CumSum, 4)
+instantiate_scan_helper(sum_bool__uint32,        bool,        uint32_t,    CumSum, 4)
 instantiate_scan_helper(sum_uint8_uint8,         uint8_t,     uint8_t,     CumSum, 4)
 instantiate_scan_helper(sum_uint16_uint16,       uint16_t,    uint16_t,    CumSum, 4)
 instantiate_scan_helper(sum_uint32_uint32,       uint32_t,    uint32_t,    CumSum, 4)

mlx/backend/metal/kernels/steel/attn/kernels/steel_attention_nax.h

@@ -0,0 +1,476 @@
+// Copyright © 2024-25 Apple Inc.
+
+using namespace mlx::steel;
+
+///////////////////////////////////////////////////////////////////////////////
+// GEMM kernels
+///////////////////////////////////////////////////////////////////////////////
+
+constant bool align_Q [[function_constant(200)]];
+constant bool align_K [[function_constant(201)]];
+
+constant bool has_mask [[function_constant(300)]];
+constant bool do_causal [[function_constant(301)]];
+constant bool has_sinks [[function_constant(302)]];
+
+template <typename T>
+struct TransformScale {
+  T scale;
+  METAL_FUNC TransformScale(T scale_) : scale(scale_) {}
+
+  METAL_FUNC T apply(T x) const {
+    return scale * x;
+  }
+};
+
+struct MaxOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return metal::max(x, y);
+  }
+};
+
+struct SumOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return x + y;
+  }
+};
+
+struct MulOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return x * y;
+  }
+};
+
+struct SubOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return x - y;
+  }
+};
+
+struct ExpSubOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return fast::exp2(x - y);
+  }
+};
+
+struct DivOp {
+  template <typename T>
+  METAL_FUNC static constexpr T apply(T x, T y) {
+    return x / y;
+  }
+};
+
+// clang-format off
+template <
+    typename T,
+    int BQ,
+    int BK,
+    int BD,
+    int WM,
+    int WN,
+    typename MaskType = float,
+    typename AccumType = float>
+[[kernel, max_total_threads_per_threadgroup(WM * WN * 32)]] void attention_nax(
+    const device T* Q [[buffer(0)]],
+    const device T* K [[buffer(1)]],
+    const device T* V [[buffer(2)]],
+    device T* O [[buffer(3)]],
+    const constant AttnParams* params [[buffer(4)]],
+    const constant AttnMaskParams* mask_params [[buffer(5), function_constant(has_mask)]],
+    const device MaskType* mask [[buffer(6), function_constant(has_mask)]],
+    const device T* sinks [[buffer(7), function_constant(has_sinks)]],
+    uint simd_lane_id [[thread_index_in_simdgroup]],
+    uint simd_group_id [[simdgroup_index_in_threadgroup]],
+    uint3 tid [[threadgroup_position_in_grid]],
+    uint3 lid [[thread_position_in_threadgroup]]) { // clang-format on
+
+  // Pacifying compiler
+  (void)lid;
+  (void)simd_lane_id;
+
+  // Move to correct block
+  ulong3 tidl{tid.x, tid.y, tid.z};
+
+  Q += tidl.z * params->Q_strides[0] + // Batch
+      tidl.y * params->Q_strides[1] + // Head
+      tidl.x * BQ * params->Q_strides[2]; // Sequence
+
+  ulong kv_head_idx = int(tid.y) / params->gqa_factor;
+  K += tidl.z * params->K_strides[0] + // Batch
+      kv_head_idx * params->K_strides[1]; // Head
+
+  V += tidl.z * params->V_strides[0] + // Batch
+      kv_head_idx * params->V_strides[1]; // Head
+
+  O += tidl.z * params->O_strides[0] + // Batch
+      tidl.y * params->O_strides[1] + // Head
+      tidl.x * BQ * params->O_strides[2]; // Sequence
+
+  if (has_mask) {
+    mask += tidl.z * mask_params->M_strides[0] + // Batch
+        tidl.y * mask_params->M_strides[1]; // Head
+  }
+
+  const metal::uniform<float> scale2 =
+      make_uniform(params->scale) * make_uniform(1.44269504089f);
+
+  // Prepare MMA tiles
+  constexpr short UQ = 16;
+  constexpr short UD = 32;
+
+  constexpr int kNWarps = WM * WN;
+  static_assert(
+      BQ >= (kNWarps * UQ) && BQ % (kNWarps * UQ) == 0,
+      "Each simdgroup must host atleast 1 simdgroup matrix along Q sequence.");
+
+  // Q seq frags per warp
+  constexpr int TQ = BQ / (kNWarps * UQ);
+  // HeadDim frags (all warps load the same frags)
+  constexpr int TD = BD / UD;
+
+  static_assert(TQ == 1, "Check TQ");
+
+  using OSubTile = NAXSubTile<AccumType, UQ, UD>;
+  NAXTile<AccumType, TQ, TD, OSubTile> Otile;
+
+  Otile.clear();
+
+  // Prepare mma tile offsets
+  const short2 simd_coord = OSubTile::NAXFrag_t::get_coord();
+  const short sm = simd_coord.y;
+  const short sn = simd_coord.x;
+  const short tm = UQ * TQ * simd_group_id;
+
+  Q += (tm + sm) * int(params->Q_strides[2]) + sn;
+  K += sm * int(params->K_strides[2]) + sn;
+  V += sm * int(params->V_strides[2]) + sn;
+
+  // Init row reduction variables
+  constexpr short kRowsPT = decltype(Otile)::kRowsPerThread;
+
+  metal::vec<AccumType, kRowsPT> max_score;
+  metal::vec<AccumType, kRowsPT> sum_score{0};
+
+  // Init to -Inf
+  STEEL_PRAGMA_UNROLL
+  for (short i = 0; i < kRowsPT; ++i) {
+    max_score[i] = Limits<AccumType>::finite_min;
+  }
+
+  if (has_sinks) {
+    STEEL_PRAGMA_UNROLL
+    for (short i = 0; i < kRowsPT; ++i) {
+      max_score[i] = M_LOG2E_F * static_cast<AccumType>(sinks[tidl.y]);
+      sum_score[i] = 1;
+    }
+  }
+
+  int kb_lim = params->NK;
+
+  if (do_causal) {
+    int q_max = (tid.x + 1) * BQ + params->qL_off;
+    kb_lim = (q_max + BK - 1) / BK;
+    kb_lim = min(params->NK, kb_lim);
+  }
+
+  const bool is_last_bq = int(tid.x) == (params->NQ_aligned);
+  // const bool is_last_tq = int(simd_group_id) >= (params->qL_rem / UQ);
+  const bool is_last_q = is_last_bq;
+
+  const short lim_rows_q = params->qL_rem - (tm + sm);
+  const short lim_rows_k = params->kL_rem - sm;
+
+  // Loop over KV seq length
+  for (int kb = 0; kb < kb_lim; kb++) {
+    const int is_last_k = (kb == (params->NK_aligned));
+
+    // Do S = Q @ K.T
+    constexpr short UDs = 16;
+    constexpr short UKs = 32;
+
+    constexpr short TDs = BD / UDs;
+    constexpr short TKs = BK / UKs;
+
+    using SSubTile = NAXSubTile<AccumType, UQ, UKs>;
+    using QSubTile = NAXSubTile<T, UQ, UDs>;
+    using KSubTile = NAXSubTile<T, UKs, UDs>;
+
+    NAXTile<AccumType, TQ, TKs, SSubTile> Stile;
+
+    Stile.clear();
+
+    STEEL_PRAGMA_UNROLL
+    for (short iq = 0; iq < TQ; iq++) {
+      STEEL_PRAGMA_UNROLL
+      for (short ik = 0; ik < TKs; ik++) {
+        STEEL_PRAGMA_UNROLL
+        for (short id = 0; id < TDs; id++) {
+          NAXTile<T, 1, 1, QSubTile> Qtile;
+          NAXTile<T, 1, 1, KSubTile> Ktile;
+
+          const int Q_load_off = iq * UQ * int(params->Q_strides[2]) + id * UDs;
+          const int K_load_off =
+              ik * UKs * int(params->K_strides[2]) + id * UDs;
+
+          if (!align_Q && is_last_q) {
+            // Qtile.load_rows(
+            //     Q + Q_load_off,
+            //     int(params->Q_strides[2]),
+            //     lim_rows_q - iq * UQ);
+            Qtile.load_safe(
+                Q + Q_load_off,
+                int(params->Q_strides[2]),
+                short2(BD, lim_rows_q - iq * UQ));
+          } else {
+            Qtile.load(Q + Q_load_off, int(params->Q_strides[2]));
+          }
+
+          if (!align_K && is_last_k) {
+            // Ktile.load_rows(
+            //     K + K_load_off,
+            //     int(params->K_strides[2]),
+            //     lim_rows_k - ik * UKs);
+            Ktile.load_safe(
+                K + K_load_off,
+                int(params->K_strides[2]),
+                short2(BD, lim_rows_k - ik * UKs));
+          } else {
+            Ktile.load(K + K_load_off, int(params->K_strides[2]));
+          }
+
+          subtile_matmad_nax(
+              Stile.subtile_at(iq, ik),
+              Qtile.subtile_at(0, 0),
+              metal::false_type{},
+              Ktile.subtile_at(0, 0),
+              metal::true_type{});
+        }
+      }
+    }
+
+    // Scale S
+    STEEL_PRAGMA_UNROLL
+    for (short ii = 0; ii < decltype(Stile)::kElemsPerTile; ii++) {
+      Stile.elems()[ii] *= float(scale2);
+    }
+
+    // Scale and Retile S
+    constexpr short UK = 16;
+    constexpr short TK = BK / UK;
+    using PSubTile = NAXSubTile<AccumType, UQ, UK>;
+
+    NAXTile<AccumType, TQ, TK, PSubTile> Ptile;
+
+    STEEL_PRAGMA_UNROLL
+    for (short ii = 0; ii < decltype(Stile)::kElemsPerTile; ii++) {
+      Ptile.elems()[ii] = Stile.elems()[ii];
+    }
+
+    // Mask out length sequence
+    if (!align_K && is_last_k) {
+      constexpr auto neg_inf = Limits<AccumType>::finite_min;
+
+      STEEL_PRAGMA_UNROLL
+      for (short iq = 0; iq < TQ; iq++) {
+        STEEL_PRAGMA_UNROLL
+        for (short ik = 0; ik < TK; ik++) {
+          const short col_pos = sn + ik * UK;
+
+          thread auto& fg = Ptile.subtile_at(iq, ik).frag_at(0, 0);
+
+          STEEL_PRAGMA_UNROLL
+          for (short ii = 0; ii < PSubTile::kFragThrRows; ii++) {
+            STEEL_PRAGMA_UNROLL
+            for (short jj = 0; jj < PSubTile::kFragThrCols; jj++) {
+              const auto loc = ii * PSubTile::kFragThrCols + jj;
+              fg[loc] = ((col_pos + jj) >= params->kL_rem) ? neg_inf : fg[loc];
+            }
+          }
+        }
+      }
+    }
+
+    // Mask out if causal
+    if (do_causal && kb >= (kb_lim - ((BQ + BK - 1) / BK) - int(!align_K))) {
+      constexpr auto neg_inf = Limits<AccumType>::finite_min;
+
+      const int base_row = tid.x * BQ + params->qL_off + tm;
+      const int base_col = kb * BK;
+
+      STEEL_PRAGMA_UNROLL
+      for (short iq = 0; iq < TQ; iq++) {
+        STEEL_PRAGMA_UNROLL
+        for (short ik = 0; ik < TK; ik++) {
+          const short row_pos = base_row + iq * UQ;
+          const short col_pos = base_col + ik * UK;
+
+          thread auto& fg = Ptile.subtile_at(iq, ik).frag_at(0, 0);
+
+          STEEL_PRAGMA_UNROLL
+          for (short ii = 0; ii < PSubTile::kFragThrRows; ii++) {
+            STEEL_PRAGMA_UNROLL
+            for (short jj = 0; jj < PSubTile::kFragThrCols; jj++) {
+              const auto r = row_pos + ii * PSubTile::kFragRowsJump + sm;
+              const auto c = col_pos + jj + sn;
+              const auto loc = ii * PSubTile::kFragThrCols + jj;
+              fg[loc] = (r < c) ? neg_inf : fg[loc];
+            }
+          }
+        }
+      }
+    }
+
+    // Other masking as needed
+    if (has_mask) {
+      constexpr auto neg_inf = Limits<AccumType>::finite_min;
+
+      const int base_row = tid.x * BQ + tm;
+      const int base_col = kb * BK;
+
+      constexpr bool is_bool = is_same_v<MaskType, bool>;
+      using melem_t = typename metal::conditional_t<is_bool, bool, AccumType>;
+      using MSubTile = NAXSubTile<melem_t, UQ, UK>;
+
+      STEEL_PRAGMA_UNROLL
+      for (short iq = 0; iq < TQ; iq++) {
+        STEEL_PRAGMA_UNROLL
+        for (short ik = 0; ik < TK; ik++) {
+          const short row_pos = base_row + iq * UQ + sm;
+          const short col_pos = base_col + ik * UK + sn;
+
+          MSubTile mfrag;
+          mfrag.load_safe(
+              mask,
+              int(mask_params->M_strides[2]),
+              Int<1>{},
+              params->qL,
+              params->kL,
+              row_pos,
+              col_pos);
+
+          thread auto& fg = Ptile.subtile_at(iq, ik).frag_at(0, 0);
+
+          STEEL_PRAGMA_UNROLL
+          for (short jj = 0; jj < MSubTile::kElemsPerFrag; jj++) {
+            if constexpr (is_bool) {
+              fg[jj] = mfrag.elems()[jj] ? fg[jj] : neg_inf;
+            } else {
+              fg[jj] += M_LOG2E_F * AccumType(mfrag.elems()[jj]);
+            }
+          }
+        }
+      }
+    }
+
+    // Do softmax
+
+    // Temp variables
+    metal::vec<AccumType, kRowsPT> new_max;
+    metal::vec<AccumType, kRowsPT> factor;
+    STEEL_PRAGMA_UNROLL
+    for (short i = 0; i < kRowsPT; ++i) {
+      new_max[i] = max_score[i];
+    }
+
+    // Row max
+    Ptile.template row_reduce<MaxOp>(new_max);
+
+    // exp(Si - rowmax(Si))
+    Ptile.template row_bin_op<ExpSubOp>(new_max);
+
+    // Factor exp(rowmax(Si) - rowmax(Si-1))
+    STEEL_PRAGMA_UNROLL
+    for (short i = 0; i < kRowsPT; ++i) {
+      factor[i] = fast::exp2(max_score[i] - new_max[i]);
+      max_score[i] = new_max[i];
+    }
+
+    // Row Sum
+    STEEL_PRAGMA_UNROLL
+    for (short i = 0; i < kRowsPT; ++i) {
+      sum_score[i] = sum_score[i] * factor[i];
+    }
+
+    Ptile.template row_reduce<SumOp>(sum_score);
+
+    // Update O
+    Otile.template row_bin_op<MulOp>(factor);
+
+    simdgroup_barrier(mem_flags::mem_none);
+
+    // Do O = P @ V
+    STEEL_PRAGMA_UNROLL
+    for (short iq = 0; iq < TQ; iq++) {
+      STEEL_PRAGMA_UNROLL
+      for (short id = 0; id < TD; id++) {
+        if constexpr (BD == 128) {
+          if (id == 2) {
+            threadgroup_barrier(mem_flags::mem_none);
+          }
+        }
+
+        STEEL_PRAGMA_UNROLL
+        for (short ik = 0; ik < TK; ik++) {
+          using VSubTile = NAXSubTile<T, UK, UD>;
+          NAXTile<T, 1, 1, VSubTile> Vtile;
+
+          const int V_load_off = ik * UK * int(params->V_strides[2]) + id * UD;
+
+          if (!align_K && is_last_k) {
+            // Vtile.load_rows(
+            //     V + V_load_off,
+            //     int(params->V_strides[2]),
+            //     lim_rows_k - ik * UK);
+            Vtile.load_safe(
+                V + V_load_off,
+                int(params->V_strides[2]),
+                short2(BD, lim_rows_k - ik * UK));
+          } else {
+            Vtile.load(V + V_load_off, int(params->V_strides[2]));
+          }
+
+          subtile_matmad_nax(
+              Otile.subtile_at(iq, id),
+              Ptile.subtile_at(iq, ik),
+              metal::bool_constant<false>{},
+              Vtile.subtile_at(0, 0),
+              metal::bool_constant<false>{});
+        }
+      }
+    }
+
+    // Prepare for next iteration
+    K += BK * int(params->K_strides[2]);
+    V += BK * int(params->V_strides[2]);
+  }
+
+  // Normalize output
+
+  threadgroup_barrier(mem_flags::mem_none);
+
+  metal::vec<AccumType, kRowsPT> rcp;
+  STEEL_PRAGMA_UNROLL
+  for (short i = 0; i < kRowsPT; ++i) {
+    rcp[i] = (1.f / sum_score[i]);
+  }
+
+  Otile.template row_bin_op<MulOp>(rcp);
+
+  // Store results
+  O += (tm + sm) * int(params->O_strides[2]) + sn;
+
+  if (!align_Q && is_last_q) {
+    if (lim_rows_q <= 0)
+      return;
+
+    // Otile.store_rows(O, params->O_strides[2], lim_rows_q);
+    Otile.store_safe(O, params->O_strides[2], short2(BD, lim_rows_q));
+  } else {
+    Otile.store(O, int(params->O_strides[2]));
+  }
+}

mlx/backend/metal/kernels/steel/attn/kernels/steel_attention_nax.metal

@@ -0,0 +1,33 @@
+// Copyright © 2024-25 Apple Inc.
+
+// clang-format off
+#include "mlx/backend/metal/kernels/utils.h"
+
+#include "mlx/backend/metal/kernels/steel/attn/nax.h"
+#include "mlx/backend/metal/kernels/steel/attn/params.h"
+#include "mlx/backend/metal/kernels/steel/attn/transforms.h"
+#include "mlx/backend/metal/kernels/steel/utils.h"
+
+#include "mlx/backend/metal/kernels/steel/attn/kernels/steel_attention_nax.h"
+
+#define instantiate_attn(tname, dtype, bq, bk, bd, wm, wn, mname, mtype) \
+  instantiate_kernel(                                                    \
+      "steel_attention_" #tname "_bq" #bq "_bk" #bk "_bd" #bd            \
+      "_wm" #wm "_wn" #wn "_mask" #mname,                                \
+  attention_nax, dtype, bq, bk, bd, wm, wn, mtype, float)
+
+#define instantiate_attn_shapes_helper(iname, itype, mname, mtype)  \
+    instantiate_attn(iname, itype, 64, 32, 128, 4, 1, mname, mtype) \
+    instantiate_attn(iname, itype, 64, 32,  64, 4, 1, mname, mtype) \
+    instantiate_attn(iname, itype, 64, 64, 128, 4, 1, mname, mtype) \
+    instantiate_attn(iname, itype, 64, 64,  64, 4, 1, mname, mtype)
+
+#define instantiate_attn_mask_helper(iname, itype) \
+    instantiate_attn_shapes_helper(iname, itype, iname, itype) \
+    instantiate_attn_shapes_helper(iname, itype, bool_, bool)
+
+instantiate_attn_mask_helper(float16, half);
+instantiate_attn_mask_helper(bfloat16, bfloat);
+
+instantiate_attn_mask_helper(float32, float);
+// clang-format on

mlx/backend/metal/kernels/steel/defines.h

@@ -1,4 +1,7 @@
 // Copyright © 2024 Apple Inc.
 
+#pragma once
+
 #define STEEL_CONST static constant constexpr const
 #define STEEL_PRAGMA_UNROLL _Pragma("clang loop unroll(full)")
+#define STEEL_PRAGMA_NO_UNROLL _Pragma("clang loop unroll(disable)")

mlx/backend/metal/kernels/steel/gemm/gemm_nax.h

@@ -0,0 +1,154 @@
+// Copyright © 2025 Apple Inc.
+
+#pragma once
+
+#include "mlx/backend/metal/kernels/steel/gemm/nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/params.h"
+
+using namespace metal;
+
+namespace mlx::steel {
+
+template <
+    typename T,
+    short SM,
+    short SN,
+    short SK,
+    short BK,
+    bool transpose_a,
+    bool transpose_b,
+    bool kAlignedM,
+    bool kAlignedN,
+    bool kAlignedK,
+    short UM,
+    short UN,
+    short UK,
+    typename AccumType = float>
+auto gemm_loop(
+    const device T* A,
+    const device T* B,
+    const constant GEMMParams* params [[buffer(4)]],
+    const short sgp_sm,
+    const short sgp_sn) {
+  constexpr short TM = SM / UM;
+  constexpr short TN = SN / UN;
+  constexpr short TK = SK / UK;
+
+  constexpr int RA = transpose_a ? TK : TM;
+  constexpr int CA = transpose_a ? TM : TK;
+
+  constexpr int RB = transpose_b ? TN : TK;
+  constexpr int CB = transpose_b ? TK : TN;
+
+  using DSubTile = NAXSubTile<AccumType, UM, UN>;
+  using ASubTile =
+      NAXSubTile<T, (transpose_a ? UK : UM), (transpose_a ? UM : UK)>;
+  using BSubTile =
+      NAXSubTile<T, (transpose_b ? UN : UK), (transpose_b ? UK : UN)>;
+
+  NAXTile<AccumType, TM, TN, DSubTile> Dtile;
+  Dtile.clear();
+
+  int gemm_k_iterations_ = params->gemm_k_iterations_aligned;
+
+  STEEL_PRAGMA_NO_UNROLL
+  for (int kk0 = 0; kk0 < gemm_k_iterations_; kk0++) {
+    threadgroup_barrier(mem_flags::mem_none);
+
+    STEEL_PRAGMA_NO_UNROLL
+    for (int kk1 = 0; kk1 < BK; kk1 += SK) {
+      NAXTile<T, RA, CA, ASubTile> Atile;
+      NAXTile<T, RB, CB, BSubTile> Btile;
+      const int k = kk1;
+
+      volatile int compiler_barrier;
+
+      const int A_offset = transpose_a ? k * params->lda : k;
+      const int B_offset = transpose_b ? k : k * params->ldb;
+
+      if constexpr (kAlignedM) {
+        Atile.load(A + A_offset, params->lda);
+      } else {
+        const short rmax = transpose_a ? SK : sgp_sm;
+        const short cmax = transpose_a ? sgp_sm : SK;
+        Atile.load_safe(A + A_offset, params->lda, short2(cmax, rmax));
+      }
+
+      if constexpr (kAlignedN) {
+        Btile.load(B + B_offset, params->ldb);
+      } else {
+        const short rmax = transpose_b ? sgp_sn : SK;
+        const short cmax = transpose_b ? SK : sgp_sn;
+        Btile.load_safe(B + B_offset, params->ldb, short2(cmax, rmax));
+      }
+
+      tile_matmad_nax(
+          Dtile,
+          Atile,
+          metal::bool_constant<transpose_a>{},
+          Btile,
+          metal::bool_constant<transpose_b>{});
+
+      (void)compiler_barrier;
+    }
+
+    A += transpose_a ? (BK * params->lda) : BK;
+    B += transpose_b ? BK : (BK * params->ldb);
+  }
+
+  if constexpr (!kAlignedK) {
+    simdgroup_barrier(mem_flags::mem_none);
+
+    const short rem_bk = params->K - gemm_k_iterations_ * BK;
+
+    STEEL_PRAGMA_NO_UNROLL
+    for (int kk1 = 0; kk1 < rem_bk; kk1 += SK) {
+      NAXTile<T, 1, 1, ASubTile> Atile;
+      NAXTile<T, 1, 1, BSubTile> Btile;
+
+      STEEL_PRAGMA_UNROLL
+      for (int mm = 0; mm < TM; mm++) {
+        STEEL_PRAGMA_UNROLL
+        for (int nn = 0; nn < TN; nn++) {
+          STEEL_PRAGMA_UNROLL
+          for (int kk = 0; kk < TK; kk++) {
+            const int m = mm * UM;
+            const int n = nn * UN;
+            const int k = kk1 + kk * UK;
+            const short psk = max(0, rem_bk - k);
+
+            const int A_offset =
+                transpose_a ? (m + k * params->lda) : (m * params->lda + k);
+            const int B_offset =
+                transpose_b ? (k + n * params->ldb) : (k * params->ldb + n);
+
+            {
+              const short psm = kAlignedM ? SM : max(0, sgp_sm - m);
+              const short rmax = transpose_a ? psk : psm;
+              const short cmax = transpose_a ? psm : psk;
+              Atile.load_safe(A + A_offset, params->lda, short2(cmax, rmax));
+            }
+
+            {
+              const short psn = kAlignedN ? SN : max(0, sgp_sn - n);
+              const short rmax = transpose_b ? psn : psk;
+              const short cmax = transpose_b ? psk : psn;
+              Btile.load_safe(B + B_offset, params->ldb, short2(cmax, rmax));
+            }
+
+            subtile_matmad_nax(
+                Dtile.subtile_at(mm, nn),
+                Atile.subtile_at(0, 0),
+                metal::bool_constant<transpose_a>{},
+                Btile.subtile_at(0, 0),
+                metal::bool_constant<transpose_b>{});
+          }
+        }
+      }
+    }
+  }
+
+  return Dtile;
+}
+
+} // namespace mlx::steel

mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_fused_nax.h

@@ -0,0 +1,207 @@
+// Copyright © 2025 Apple Inc.
+
+using namespace mlx::steel;
+
+constant bool has_batch [[function_constant(10)]];
+
+constant bool use_out_source [[function_constant(100)]];
+constant bool do_axpby [[function_constant(110)]];
+
+constant bool align_M [[function_constant(200)]];
+constant bool align_N [[function_constant(201)]];
+constant bool align_K [[function_constant(202)]];
+
+// clang-format off
+template <
+    bool kAlignedM,
+    bool kAlignedN,
+    typename NAXTile_t,
+    typename T>
+void gemm_epilogue(
+    thread NAXTile_t& Dtile,
+    const device T* C,
+    const constant GEMMParams* params,
+    const constant GEMMAddMMParams* addmm_params,
+    const short sgp_sm, 
+    const short sgp_sn) { // clang-format on
+
+  (void)params;
+
+  constexpr short UM = NAXTile_t::kSubTileRows;
+  constexpr short UN = NAXTile_t::kSubTileCols;
+  using CSubTile = NAXSubTile<T, UM, UN>;
+
+  using V = typename NAXTile_t::elem_type;
+
+  constexpr short TM = NAXTile_t::kTileRows;
+  constexpr short TN = NAXTile_t::kTileCols;
+  constexpr short kElemsPerSubTile = NAXTile_t::kElemsPerSubTile;
+
+  STEEL_PRAGMA_UNROLL
+  for (short mm = 0; mm < TM; mm++) {
+    STEEL_PRAGMA_UNROLL
+    for (short nn = 0; nn < TN; nn++) {
+      const short m = mm * UM;
+      const short n = nn * UN;
+
+      CSubTile CTile;
+
+      if constexpr (kAlignedM && kAlignedN) {
+        CTile.load(C, addmm_params->ldc, addmm_params->fdc, m, n);
+      } else {
+        CTile.load_safe(
+            C, addmm_params->ldc, addmm_params->fdc, sgp_sm, sgp_sn, m, n);
+      }
+
+      auto delems = Dtile.subtile_at(mm, nn).elems();
+      auto celems = CTile.elems();
+
+      STEEL_PRAGMA_UNROLL
+      for (short i = 0; i < kElemsPerSubTile; i++) {
+        if (do_axpby) {
+          delems[i] = addmm_params->alpha * delems[i] +
+              addmm_params->beta * static_cast<V>(celems[i]);
+        } else {
+          delems[i] += static_cast<V>(celems[i]);
+        }
+      }
+    }
+  }
+}
+
+// clang-format off
+template <
+    typename T,
+    int BM,
+    int BN,
+    int BK,
+    int WM,
+    int WN,
+    bool transpose_a,
+    bool transpose_b,
+    typename AccumType = float>
+[[kernel, max_total_threads_per_threadgroup(WM* WN * 32)]] void gemm(
+    const device T* A [[buffer(0)]],
+    const device T* B [[buffer(1)]],
+    const device T* C [[buffer(2), function_constant(use_out_source)]],
+    device T* D [[buffer(3)]],
+    const constant GEMMParams* params [[buffer(4)]],
+    const constant GEMMAddMMParams* addmm_params [[buffer(5), function_constant(use_out_source)]],
+    const constant int* batch_shape [[buffer(6), function_constant(has_batch)]],
+    const constant int64_t* batch_strides [[buffer(7), function_constant(has_batch)]],
+    uint simd_group_id [[simdgroup_index_in_threadgroup]],
+    uint3 tid [[threadgroup_position_in_grid]]) { // clang-format on
+  // Find block
+  const int tid_y = ((tid.y) << params->swizzle_log) +
+      ((tid.x) & ((1 << params->swizzle_log) - 1));
+  const int tid_x = (tid.x) >> params->swizzle_log;
+
+  // Exit early if out of bounds
+  if (params->tiles_n <= tid_x || params->tiles_m <= tid_y) {
+    return;
+  }
+
+  // Adjust for batch
+  if (has_batch) {
+    const constant auto* A_bstrides = batch_strides;
+    const constant auto* B_bstrides = batch_strides + params->batch_ndim;
+
+    ulong2 batch_offsets = elem_to_loc_broadcast(
+        tid.z, batch_shape, A_bstrides, B_bstrides, params->batch_ndim);
+
+    A += batch_offsets.x;
+    B += batch_offsets.y;
+
+    if (use_out_source) {
+      const constant auto* C_bstrides = B_bstrides + params->batch_ndim;
+      C += elem_to_loc(tid.z, batch_shape, C_bstrides, params->batch_ndim);
+    }
+  } else {
+    A += params->batch_stride_a * tid.z;
+    B += params->batch_stride_b * tid.z;
+
+    if (use_out_source) {
+      C += addmm_params->batch_stride_c * tid.z;
+    }
+  }
+
+  D += params->batch_stride_d * tid.z;
+
+  // Prepare threadgroup memory
+  threadgroup_barrier(mem_flags::mem_none);
+
+  // Find block in A, B, C
+  const int c_row = tid_y * BM;
+  const int c_col = tid_x * BN;
+  const size_t c_row_long = size_t(c_row);
+  const size_t c_col_long = size_t(c_col);
+
+  A += transpose_a ? c_row_long : c_row_long * params->lda;
+  B += transpose_b ? c_col_long * params->ldb : c_col_long;
+  D += c_row_long * params->ldd + c_col_long;
+
+  if (use_out_source) {
+    C += c_row_long * addmm_params->ldc + c_col_long * addmm_params->fdc;
+  }
+
+  constexpr short UM = 16;
+  constexpr short UN = 32;
+  constexpr short UK = 16;
+  constexpr short SM = BM / WM;
+  constexpr short SN = BN / WN;
+  constexpr short SK = 32;
+
+  constexpr short TM = SM / UM;
+  constexpr short TN = SN / UN;
+
+  const short tm = SM * (simd_group_id / WN);
+  const short tn = SN * (simd_group_id % WN);
+
+  const short sgp_sm = align_M ? SM : min(SM, short(params->M - (c_row + tm)));
+  const bool is_unaligned_sm = align_M ? false : (sgp_sm != SM);
+
+  const short sgp_sn = align_N ? SN : min(SN, short(params->N - (c_col + tn)));
+  const bool is_unaligned_sn = align_N ? false : (sgp_sn != SN);
+
+  A += transpose_a ? tm : (tm * params->lda);
+  B += transpose_b ? (tn * params->ldb) : tn;
+  D += tm * params->ldd + tn;
+
+  if (use_out_source) {
+    C += tm * addmm_params->ldc + tn * addmm_params->fdc;
+  }
+
+  using DSubTile = NAXSubTile<AccumType, UM, UN>;
+  NAXTile<AccumType, TM, TN, DSubTile> Dtile;
+
+  dispatch_bool(align_K, [&](auto kAlignedK) {
+    dispatch_bool(align_M || !is_unaligned_sm, [&](auto kAlignedM) {
+      dispatch_bool(align_N || !is_unaligned_sn, [&](auto kAlignedN) {
+        Dtile = gemm_loop<
+            T,
+            SM,
+            SN,
+            SK,
+            BK,
+            transpose_a,
+            transpose_b,
+            kAlignedM.value,
+            kAlignedN.value,
+            kAlignedK.value,
+            UM,
+            UN,
+            UK,
+            AccumType>(A, B, params, sgp_sm, sgp_sn);
+        if (use_out_source) {
+          gemm_epilogue<kAlignedM.value, kAlignedN.value>(
+              Dtile, C, params, addmm_params, sgp_sm, sgp_sn);
+        }
+        if constexpr (kAlignedM && kAlignedN) {
+          Dtile.store(D, int(params->ldd));
+        } else {
+          Dtile.store_safe(D, int(params->ldd), short2(sgp_sn, sgp_sm));
+        }
+      });
+    });
+  });
+}

mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_fused_nax.metal

@@ -0,0 +1,35 @@
+// Copyright © 2025 Apple Inc.
+
+#include <metal_stdlib>
+
+#include "mlx/backend/metal/kernels/utils.h"
+
+#include "mlx/backend/metal/kernels/steel/gemm/gemm_nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/params.h"
+#include "mlx/backend/metal/kernels/steel/gemm/transforms.h"
+#include "mlx/backend/metal/kernels/steel/utils.h"
+
+#include "mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_fused_nax.h"
+
+// clang-format off
+#define instantiate_gemm(tname, trans_a, trans_b, iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+  instantiate_kernel(                                                                             \
+      "steel_gemm_fused_nax_" #tname "_"  #iname "_" #oname                                       \
+      "_bm" #bm "_bn" #bn "_bk" #bk "_wm" #wm "_wn" #wn,                                          \
+  gemm, itype, bm, bn, bk, wm, wn, trans_a, trans_b, float)
+
+#define instantiate_gemm_transpose_helper(iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+    instantiate_gemm(nn, false, false, iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+    instantiate_gemm(nt, false, true , iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+    instantiate_gemm(tn, true , false, iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+    instantiate_gemm(tt, true , true , iname, itype, oname, otype, bm, bn, bk, wm, wn)
+
+#define instantiate_gemm_shapes_helper(iname, itype, oname, otype) \
+    instantiate_gemm_transpose_helper(iname, itype, oname, otype,  64,  64, 256, 2, 2) \
+    instantiate_gemm_transpose_helper(iname, itype, oname, otype, 128, 128, 512, 4, 4)
+
+instantiate_gemm_shapes_helper(float16, half, float16, half);
+instantiate_gemm_shapes_helper(bfloat16, bfloat, bfloat16, bfloat);
+instantiate_gemm_shapes_helper(float32, float, float32, float);
+// clang-format on

mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_gather_nax.h

@@ -0,0 +1,132 @@
+// Copyright © 2024 Apple Inc.
+
+using namespace mlx::steel;
+
+constant bool align_M [[function_constant(200)]];
+constant bool align_N [[function_constant(201)]];
+constant bool align_K [[function_constant(202)]];
+
+template <
+    typename T,
+    int BM,
+    int BN,
+    int BK,
+    int WM,
+    int WN,
+    bool transpose_a,
+    bool transpose_b,
+    typename AccumType = float>
+[[kernel, max_total_threads_per_threadgroup(WM* WN * 32)]] void
+gather_mm_rhs_nax(
+    const device T* A [[buffer(0)]],
+    const device T* B [[buffer(1)]],
+    const device uint32_t* rhs_indices [[buffer(2)]],
+    device T* C [[buffer(3)]],
+    const constant GEMMParams* params [[buffer(4)]],
+    uint simd_group_id [[simdgroup_index_in_threadgroup]],
+    uint3 tid [[threadgroup_position_in_grid]]) {
+  constexpr short UM = 16;
+  constexpr short UN = 32;
+  constexpr short UK = 16;
+  constexpr short SM = BM / WM;
+  constexpr short SN = BN / WN;
+  constexpr short SK = 32;
+  constexpr short TM = SM / UM;
+  constexpr short TN = SN / UN;
+
+  if (params->tiles_n <= static_cast<int>(tid.x) ||
+      params->tiles_m <= static_cast<int>(tid.y)) {
+    return;
+  }
+
+  // Find the block in A, B, C
+  const int c_row = tid.y * BM;
+  const int c_col = tid.x * BN;
+  const size_t c_row_long = size_t(c_row);
+  const size_t c_col_long = size_t(c_col);
+
+  A += transpose_a ? c_row_long : c_row_long * params->lda;
+  B += transpose_b ? c_col_long * params->ldb : c_col_long;
+  C += c_row_long * params->ldd + c_col_long;
+  rhs_indices += c_row;
+
+  const short tm = SM * (simd_group_id / WN);
+  const short tn = SN * (simd_group_id % WN);
+
+  const short sgp_sm = align_M ? SM : min(SM, short(params->M - (c_row + tm)));
+  const bool is_unaligned_sm = align_M ? false : (sgp_sm != SM);
+
+  const short sgp_sn = align_N ? SN : min(SN, short(params->N - (c_col + tn)));
+  const bool is_unaligned_sn = align_N ? false : (sgp_sn != SN);
+
+  A += transpose_a ? tm : (tm * params->lda);
+  B += transpose_b ? (tn * params->ldb) : tn;
+  C += tm * params->ldd + tn;
+  rhs_indices += tm;
+
+  // Do as many matmuls as necessary
+  uint32_t index;
+  short offset;
+  uint32_t index_next = rhs_indices[0];
+  short offset_next = 0;
+  int n = 0;
+  while (n < sgp_sm) {
+    n++;
+    offset = offset_next;
+    index = index_next;
+    offset_next = sgp_sm;
+    for (; n < sgp_sm; n++) {
+      if (rhs_indices[n] != index) {
+        offset_next = n;
+        index_next = rhs_indices[n];
+        break;
+      }
+    }
+    threadgroup_barrier(mem_flags::mem_none);
+
+    using DSubTile = NAXSubTile<AccumType, UM, UN>;
+    NAXTile<AccumType, TM, TN, DSubTile> Ctile;
+
+    dispatch_bool(align_K, [&](auto kAlignedK) {
+      dispatch_bool(align_M || !is_unaligned_sm, [&](auto kAlignedM) {
+        dispatch_bool(align_N || !is_unaligned_sn, [&](auto kAlignedN) {
+          auto do_gemm = gemm_loop<
+              T,
+              SM,
+              SN,
+              SK,
+              BK,
+              transpose_a,
+              transpose_b,
+              kAlignedM.value,
+              kAlignedN.value,
+              kAlignedK.value,
+              UM,
+              UN,
+              UK,
+              AccumType>;
+          Ctile = do_gemm(
+              A, B + index * params->batch_stride_b, params, sgp_sm, sgp_sn);
+
+          if constexpr (kAlignedN.value) {
+            if (offset_next - offset == SM) {
+              Ctile.store(C, int(params->ldd));
+            } else {
+              Ctile.store_slice(
+                  C,
+                  int(params->ldd),
+                  short2(0, offset),
+                  short2(SN, offset_next));
+            }
+          } else {
+            Ctile.store_slice(
+                C,
+                int(params->ldd),
+                short2(0, offset),
+                short2(sgp_sn, offset_next));
+          }
+        });
+      });
+    });
+  }
+}

mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_gather_nax.metal

@@ -0,0 +1,39 @@
+// Copyright © 2024 Apple Inc.
+
+#include <metal_stdlib>
+
+#include "mlx/backend/metal/kernels/steel/gemm/gemm_nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/kernels/steel_gemm_gather_nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/nax.h"
+#include "mlx/backend/metal/kernels/steel/gemm/params.h"
+#include "mlx/backend/metal/kernels/steel/utils.h"
+#include "mlx/backend/metal/kernels/utils.h"
+
+// clang-format off
+#define instantiate_gather_mm_rhs(tname, trans_a, trans_b, iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+  instantiate_kernel(                                                             \
+      "steel_gather_mm_rhs_nax_" #tname "_" #iname "_" #oname "_bm" #bm "_bn" #bn \
+      "_bk" #bk "_wm" #wm "_wn" #wn,                                              \
+      gather_mm_rhs_nax,                                                          \
+      itype,                                                                      \
+      bm,                                                                         \
+      bn,                                                                         \
+      bk,                                                                         \
+      wm,                                                                         \
+      wn,                                                                         \
+      trans_a,                                                                    \
+      trans_b,                                                                    \
+      float)
+
+#define instantiate_gather_mm_rhs_transpose_helper(iname, itype, oname, otype, bm, bn, bk, wm, wn) \
+  instantiate_gather_mm_rhs(nn, false, false, iname, itype, oname, otype, bm, bn, bk, wm, wn)  \
+  instantiate_gather_mm_rhs(nt, false,  true, iname, itype, oname, otype, bm, bn, bk, wm, wn)
+
+#define instantiate_gather_mm_shapes_helper(iname, itype, oname, otype)                      \
+  instantiate_gather_mm_rhs_transpose_helper(iname, itype, oname, otype, 16, 128, 128, 1, 4) \
+  instantiate_gather_mm_rhs_transpose_helper(iname, itype, oname, otype, 32, 128, 128, 1, 4) \
+  instantiate_gather_mm_rhs_transpose_helper(iname, itype, oname, otype, 64, 128, 128, 2, 4)
+// clang-format on
+
+instantiate_gather_mm_shapes_helper(float16, half, float16, half);
+instantiate_gather_mm_shapes_helper(bfloat16, bfloat, bfloat16, bfloat);

mlx/backend/metal/kernels/steel/utils/integral_constant.h

@@ -74,6 +74,44 @@ integral_const_binop(>=, operator>=);
 integral_const_binop(&&, operator&&);
 integral_const_binop(||, operator||);
 
+template <typename T, typename = metal::enable_if_t<!is_integral_v<T>>>
+METAL_FUNC constexpr auto operator||(true_type, T) {
+  return true_type{};
+}
+template <typename T, typename = metal::enable_if_t<!is_integral_v<T>>>
+METAL_FUNC constexpr auto operator||(T, true_type) {
+  return true_type{};
+}
+
+template <typename T, typename = metal::enable_if_t<!is_integral_v<T>>>
+METAL_FUNC constexpr auto operator&&(false_type, T) {
+  return false_type{};
+}
+
+template <typename T, typename = metal::enable_if_t<!is_integral_v<T>>>
+METAL_FUNC constexpr auto operator&&(T, false_type) {
+  return false_type{};
+}
+
+// Dispatch utilities
+template <typename F>
+void dispatch_bool(bool v, F f) {
+  if (v) {
+    f(true_type{});
+  } else {
+    f(false_type{});
+  }
+}
+
+template <int start, int stop, int step, typename F>
+constexpr void const_for_loop(F f) {
+  if constexpr (start < stop) {
+    constexpr auto idx = Int<start>{};
+    f(idx);
+    const_for_loop<start + step, stop, step, F>(f);
+  }
+}
+
 #undef integral_const_binop
 
 ///////////////////////////////////////////////////////////////////////////////

mlx/backend/metal/matmul.cpp

@@ -173,7 +173,7 @@ ensure_batch_contiguous(const array& x, metal::Device& d, const Stream& s) {
 ///////////////////////////////////////////////////////////////////////////////
 
 template <bool CHECK_AB>
-void steel_matmul_regular_axpby(
+void steel_matmul_regular_axpby_nax(
     const Stream& s,
     metal::Device& d,
     const array& a,
@@ -200,6 +200,190 @@ void steel_matmul_regular_axpby(
     float beta /* = 0.0f */) {
   using namespace mlx::steel;
 
+  // Determine dispatch kernel
+  int bm = 128, bn = 128, bk = 512;
+  int wm = 4, wn = 4;
+
+  // Prepare kernel name
+  std::ostringstream kname;
+
+  // clang-format off
+  kname << "steel_gemm_fused_nax_"
+        << (transpose_a ? 't' : 'n')
+        << (transpose_b ? 't' : 'n')
+        << "_" << type_to_name(a)
+        << "_" << type_to_name(out)
+        << "_bm" << bm << "_bn" << bn << "_bk" << bk
+        << "_wm" << wm << "_wn" << wn; // clang-format on
+
+  std::string base_name = kname.str();
+
+  const bool has_batch = (batch_shape.size() > 1);
+  const bool use_out_source = CHECK_AB && (alpha != 0.0f || beta != 1.0f);
+  const bool do_axpby = use_out_source && (alpha != 1.0f || beta != 1.0f);
+  const bool align_M = (M % bm) == 0;
+  const bool align_N = (N % bn) == 0;
+  const bool align_K = (K % bk) == 0;
+
+  metal::MTLFCList func_consts = {
+      {&has_batch, MTL::DataType::DataTypeBool, 10},
+      {&use_out_source, MTL::DataType::DataTypeBool, 100},
+      {&do_axpby, MTL::DataType::DataTypeBool, 110},
+      {&align_M, MTL::DataType::DataTypeBool, 200},
+      {&align_N, MTL::DataType::DataTypeBool, 201},
+      {&align_K, MTL::DataType::DataTypeBool, 202},
+  };
+
+  // clang-format off
+  kname << "_has_batch_" << (has_batch ? 't' : 'n')
+        << "_use_out_source_" << (use_out_source ? 't' : 'n')
+        << "_do_axpby_" << (do_axpby ? 't' : 'n')
+        << "_align_M_" << (align_M ? 't' : 'n')
+        << "_align_N_" << (align_N ? 't' : 'n')
+        << "_align_K_" << (align_K ? 't' : 'n'); // clang-format on
+
+  std::string hash_name = kname.str();
+
+  // Encode and dispatch kernel
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  auto kernel = get_steel_gemm_fused_kernel(
+      /* metal::Device& d = */ d,
+      /* const std::string& kernel_name = */ base_name,
+      /* const std::string& hash_name = */ hash_name,
+      /* const metal::MTLFCList& func_consts = */ func_consts,
+      /* const array& out = */ out,
+      /* bool transpose_a = */ transpose_a,
+      /* bool transpose_b = */ transpose_b,
+      /* int bm = */ bm,
+      /* int bn = */ bn,
+      /* int bk = */ bk,
+      /* int wm = */ wm,
+      /* int wn = */ wn);
+
+  compute_encoder.set_compute_pipeline_state(kernel);
+
+  // Use problem size to determine threadblock swizzle
+  int tn = (N + bn - 1) / bn;
+  int tm = (M + bm - 1) / bm;
+
+  // TODO: Explore device-based tuning for swizzle
+  int swizzle_log = tm <= 3 ? 0 : 1;
+
+  // Prepare steel matmul params
+  GEMMParams params{
+      /* const int M = */ M,
+      /* const int N = */ N,
+      /* const int K = */ K,
+      /* const int lda = */ lda,
+      /* const int ldb = */ ldb,
+      /* const int ldd = */ ldd,
+      /* const int tiles_n = */ tn,
+      /* const int tiles_m = */ tm,
+      /* const int64_t batch_stride_a = */ A_batch_stride,
+      /* const int64_t batch_stride_b = */ B_batch_stride,
+      /* const int64_t batch_stride_d = */ matrix_stride_out,
+      /* const int swizzle_log = */ swizzle_log,
+      /* const int gemm_k_iterations_aligned = */ (K / bk),
+      /* const int batch_ndim = */ int(batch_shape.size())};
+
+  // Prepare launch grid params
+  int tile = 1 << swizzle_log;
+  tm = (tm + tile - 1) / tile;
+  tn = tn * tile;
+
+  MTL::Size group_dims = MTL::Size(32, wn, wm);
+  MTL::Size grid_dims = MTL::Size(tn, tm, batch_size_out);
+
+  // Launch kernel
+  compute_encoder.set_input_array(a, 0);
+  compute_encoder.set_input_array(b, 1);
+  compute_encoder.set_output_array(out, 3);
+
+  compute_encoder.set_bytes(params, 4);
+
+  if (has_batch) {
+    compute_encoder.set_vector_bytes(batch_shape, 6);
+    compute_encoder.set_vector_bytes(batch_strides, 7);
+  }
+
+  if (use_out_source) {
+    int ldc = c.strides()[c.ndim() - 2];
+    int fdc = c.strides()[c.ndim() - 1];
+
+    GEMMAddMMParams params{
+        /* const int ldc = */ ldc,
+        /* const int fdc = */ fdc,
+        /* const int64_t batch_stride_c = */ C_batch_stride,
+        /* const float alpha = */ alpha,
+        /* const float beta = */ beta};
+
+    compute_encoder.set_input_array(c, 2);
+    compute_encoder.set_bytes(params, 5);
+  }
+
+  compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
+
+  // Record copies
+  d.add_temporaries(std::move(copies), s.index);
+}
+
+template <bool CHECK_AB>
+void steel_matmul_regular_axpby(
+    const Stream& s,
+    metal::Device& d,
+    const array& a,
+    const array& b,
+    const array& c,
+    array& out,
+    int M,
+    int N,
+    int K,
+    int batch_size_out,
+    int lda,
+    int ldb,
+    int ldd,
+    bool transpose_a,
+    bool transpose_b,
+    std::vector<array>& copies,
+    Shape batch_shape,
+    Strides batch_strides,
+    int64_t A_batch_stride,
+    int64_t B_batch_stride,
+    int64_t matrix_stride_out,
+    int64_t C_batch_stride /* = 0*/,
+    float alpha /* = 1.0f */,
+    float beta /* = 0.0f */) {
+  if (metal::is_nax_available() && !issubdtype(a.dtype(), complexfloating) &&
+      (env::enable_tf32() || a.dtype() != float32)) {
+    return steel_matmul_regular_axpby_nax<CHECK_AB>(
+        /* const Stream& s = */ s,
+        /* metal::Device& d = */ d,
+        /* const array& a = */ a,
+        /* const array& b = */ b,
+        /* const array& c = */ c,
+        /* array& out = */ out,
+        /* int M = */ M,
+        /* int N = */ N,
+        /* int K = */ K,
+        /* int batch_size_out = */ batch_size_out,
+        /* int lda = */ lda,
+        /* int ldb = */ ldb,
+        /* int ldd = */ ldd,
+        /* bool transpose_a = */ transpose_a,
+        /* bool transpose_b = */ transpose_b,
+        /* std::vector<array>& copies = */ copies,
+        /* Shape batch_shape = */ batch_shape,
+        /* Strides batch_strides = */ batch_strides,
+        /* int64_t A_batch_stride = */ A_batch_stride,
+        /* int64_t B_batch_stride = */ B_batch_stride,
+        /* int64_t matrix_stride_out = */ matrix_stride_out,
+        /* int64_t C_batch_stride = */ C_batch_stride,
+        /* float alpha = */ alpha,
+        /* float beta = */ beta);
+  }
+
+  using namespace mlx::steel;
+
   // Determine dispatch kernel
   int bm = 64, bn = 64, bk = 16;
   int wm = 2, wn = 2;
@@ -211,11 +395,11 @@ void steel_matmul_regular_axpby(
   std::ostringstream kname;
 
   // clang-format off
-  kname << "steel_gemm_fused_" 
+  kname << "steel_gemm_fused_"
         << (transpose_a ? 't' : 'n')
-        << (transpose_b ? 't' : 'n') 
-        << "_" << type_to_name(a) 
-        << "_" << type_to_name(out) 
+        << (transpose_b ? 't' : 'n')
+        << "_" << type_to_name(a)
+        << "_" << type_to_name(out)
         << "_bm" << bm << "_bn" << bn << "_bk" << bk
         << "_wm" << wm << "_wn" << wn; // clang-format on
 
@@ -380,14 +564,14 @@ void steel_gemm_splitk_axpby(
   std::ostringstream kname;
 
   // clang-format off
-  kname << "steel_gemm_splitk_" 
+  kname << "steel_gemm_splitk_"
         << (transpose_a ? 't' : 'n')
-        << (transpose_b ? 't' : 'n') 
-        << "_" << type_to_name(a) 
-        << "_" << type_to_name(C_split) 
+        << (transpose_b ? 't' : 'n')
+        << "_" << type_to_name(a)
+        << "_" << type_to_name(C_split)
         << "_bm" << bm << "_bn" << bn << "_bk" << bk
-        << "_wm" << wm << "_wn" << wn 
-        << "_MN_" << (mn_aligned ? "t" : "n") << "aligned" 
+        << "_wm" << wm << "_wn" << wn
+        << "_MN_" << (mn_aligned ? "t" : "n") << "aligned"
         << "_K_" << (k_aligned ? "t" : "n") << "aligned"; // clang-format on
 
   // Encode and dispatch gemm kernel
@@ -721,10 +905,10 @@ void gemv_axbpy(
   const bool do_axpby = CHECK_AB && (alpha != 1.0f || beta != 0.0f);
 
   // clang-format off
-  kname << "_bm" << bm << "_bn" << bn 
-        << "_sm" << sm << "_sn" << sn 
+  kname << "_bm" << bm << "_bn" << bn
+        << "_sm" << sm << "_sn" << sn
         << "_tm" << tm << "_tn" << tn
-        << "_nc" << !contiguous_kernel 
+        << "_nc" << !contiguous_kernel
         << "_axpby" << do_axpby; // clang-format on
 
   // Encode and dispatch kernel
@@ -1572,6 +1756,149 @@ void gather_mm_rhs(
   compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
 }
 
+void gather_mm_rhs_nax(
+    const array& a_,
+    const array& b_,
+    const array& indices_,
+    array& out,
+    metal::Device& d,
+    const Stream& s) {
+  array indices = ensure_row_contiguous(indices_, d, s);
+  auto [transpose_b, ldb, b] = ensure_batch_contiguous(b_, d, s);
+
+  // Broadcast a with indices. If we are here that means lhs_indices were not
+  // provided so the lhs_indices are implied to be the shape of a broadcasted
+  // with rhs_indices. We need only broadcast a and copy it as if applying the
+  // lhs_indices.
+  auto broadcast_with_indices = [&d, &s, &indices](const array& x) {
+    if (x.size() / x.shape(-2) / x.shape(-1) == indices.size()) {
+      return ensure_row_contiguous(x, d, s);
+    }
+
+    auto x_shape = indices.shape();
+    x_shape.push_back(x.shape(-2));
+    x_shape.push_back(x.shape(-1));
+    array new_x(std::move(x_shape), x.dtype(), nullptr, {});
+    broadcast(x, new_x);
+    return ensure_row_contiguous(new_x, d, s);
+  };
+  array a = broadcast_with_indices(a_);
+
+  // Extract the matmul shapes
+  int K = a.shape(-1);
+  int M = a.size() / K;
+  int N = b.shape(-1);
+  int lda = a.strides()[a.ndim() - 2]; // should be K
+  int E = b.shape(0);
+
+  // Define the dispatch blocks
+  int bm, bn = 128, bk = 128, wm, wn = 4;
+  if (M / E > 48) {
+    bm = 64;
+    wm = 2;
+  } else if (M / E > 24) {
+    bm = 32l;
+    wm = 1;
+  } else {
+    bm = 16;
+    wm = 1;
+  }
+
+  const bool align_M = (M % bm) == 0;
+  const bool align_N = (N % bn) == 0;
+  const bool align_K = (K % bk) == 0;
+
+  // Define the kernel name
+  std::string base_name;
+  base_name.reserve(64);
+  concatenate(
+      base_name,
+      "steel_gather_mm_rhs_nax_n",
+      transpose_b ? 't' : 'n',
+      '_',
+      type_to_name(a),
+      '_',
+      type_to_name(out),
+      "_bm",
+      bm,
+      "_bn",
+      bn,
+      "_bk",
+      bk,
+      "_wm",
+      wm,
+      "_wn",
+      wn);
+
+  metal::MTLFCList func_consts = {
+      {&align_M, MTL::DataType::DataTypeBool, 200},
+      {&align_N, MTL::DataType::DataTypeBool, 201},
+      {&align_K, MTL::DataType::DataTypeBool, 202},
+  };
+
+  // And the kernel hash that includes the function constants
+  std::string hash_name;
+  hash_name.reserve(128);
+  concatenate(
+      hash_name,
+      base_name,
+      "_align_M_",
+      align_M ? 't' : 'n',
+      "_align_N_",
+      align_N ? 't' : 'n',
+      "_align_K_",
+      align_K ? 't' : 'n');
+
+  // Get and set the kernel
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  auto kernel = get_steel_gemm_gather_kernel(
+      d,
+      base_name,
+      hash_name,
+      func_consts,
+      out,
+      false,
+      transpose_b,
+      bm,
+      bn,
+      bk,
+      wm,
+      wn,
+      true);
+  compute_encoder.set_compute_pipeline_state(kernel);
+
+  // Prepare the matmul params
+  auto batch_stride_b = b.ndim() > 2 ? b.strides()[b.ndim() - 3] : b.size();
+  steel::GEMMParams params{
+      /* const int M = */ M,
+      /* const int N = */ N,
+      /* const int K = */ K,
+      /* const int lda = */ lda,
+      /* const int ldb = */ static_cast<int>(ldb),
+      /* const int ldd = */ N,
+      /* const int tiles_n = */ (N + bn - 1) / bn,
+      /* const int tiles_m = */ (M + bm - 1) / bm,
+      /* const int64_t batch_stride_a = */ 0,
+      /* const int64_t batch_stride_b = */ static_cast<int64_t>(batch_stride_b),
+      /* const int64_t batch_stride_d = */ 0,
+      /* const int swizzle_log = */ 0,
+      /* const int gemm_k_iterations_aligned = */ (K / bk),
+      /* const int batch_ndim = */ 0};
+
+  // Prepare the grid
+  MTL::Size group_dims = MTL::Size(32, wn, wm);
+  MTL::Size grid_dims = MTL::Size(params.tiles_n, params.tiles_m, 1);
+
+  // Launch kernel
+  compute_encoder.set_input_array(a, 0);
+  compute_encoder.set_input_array(b, 1);
+  compute_encoder.set_input_array(indices, 2);
+  compute_encoder.set_output_array(out, 3);
+  compute_encoder.set_bytes(params, 4);
+
+  compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
+}
+
 void gather_mv(
     const array& mat_,
     const array& vec_,
@@ -1855,6 +2182,10 @@ void GatherMM::eval_gpu(const std::vector<array>& inputs, array& out) {
   // We are walking a in order and b is also in order so we can batch up the
   // matmuls and reuse reading a and b.
   if (M == 1 && right_sorted_ == true) {
+    if (metal::is_nax_available() &&
+        (env::enable_tf32() || a.dtype() != float32)) {
+      return gather_mm_rhs_nax(a, b, rhs_indices, out, d, s);
+    }
     gather_mm_rhs(a, b, rhs_indices, out, d, s);
     return;
   }

mlx/backend/metal/quantized.cpp

@@ -451,6 +451,206 @@ void qvm(
   compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
 }
 
+void qmm_nax(
+    const array& x,
+    const array& w,
+    const array& scales,
+    const std::optional<array>& biases,
+    array& out,
+    bool transpose,
+    int group_size,
+    int bits,
+    int M,
+    int N,
+    int K,
+    metal::Device& d,
+    const Stream& s,
+    const std::string& mode) {
+  int B = out.size() / M / N;
+
+  int wm = 2;
+  int wn = 2;
+  int bm = 64;
+  int bn = 64;
+  int bk = 64;
+  MTL::Size group_dims(32, wn, wm);
+  MTL::Size grid_dims((N + bn - 1) / bn, (M + bm - 1) / bm, B);
+
+  std::string kname;
+  kname.reserve(64);
+  bool aligned = N % 64 == 0;
+  bool batched = B > 1;
+  std::string type_string = get_type_string(x.dtype());
+  concatenate(
+      kname,
+      mode + (transpose ? "_qmm_t_nax_" : "_qmm_n_nax_"),
+      type_string,
+      "_gs_",
+      group_size,
+      "_b_",
+      bits,
+      "_bm",
+      bm,
+      "_bn",
+      bn,
+      "_bk",
+      bk,
+      "_wm",
+      wm,
+      "_wn",
+      wn,
+      transpose ? (aligned ? "_alN_true" : "_alN_false") : "",
+      batched ? "_batch_1" : "_batch_0");
+  std::string template_def;
+  MTL::ComputePipelineState* kernel;
+  if (transpose) {
+    kernel = get_quantized_kernel_wrapped(
+        d,
+        kname,
+        "qmm_t_nax",
+        mode,
+        type_string,
+        group_size,
+        bits,
+        aligned,
+        batched);
+  } else {
+    kernel = get_quantized_kernel_wrapped(
+        d, kname, "qmm_n_nax", mode, type_string, group_size, bits, batched);
+  }
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  compute_encoder.set_compute_pipeline_state(kernel);
+
+  int c = 0;
+  compute_encoder.set_input_array(w, c++);
+  compute_encoder.set_input_array(scales, c++);
+  if (biases) {
+    compute_encoder.set_input_array(*biases, c++);
+  }
+  compute_encoder.set_input_array(x, c++);
+  compute_encoder.set_output_array(out, c++);
+  compute_encoder.set_bytes(K, c++);
+  compute_encoder.set_bytes(N, c++);
+  compute_encoder.set_bytes(M, c++);
+  add_strides_and_shapes(compute_encoder, B <= 1, x, w, scales, biases, c);
+
+  compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
+}
+
+void gather_qmm_nax(
+    const array& x,
+    const array& w,
+    const array& scales,
+    const std::optional<array>& biases,
+    const array& lhs_indices,
+    const array& rhs_indices,
+    array& out,
+    bool transpose,
+    int group_size,
+    int bits,
+    int M,
+    int N,
+    int K,
+    metal::Device& d,
+    const Stream& s,
+    const std::string& mode) {
+  int B = out.size() / M / N;
+
+  int wm = 2;
+  int wn = 2;
+  int bm = 64;
+  int bn = 64;
+  int bk = 32;
+  MTL::Size group_dims(32, wn, wm);
+  MTL::Size grid_dims((N + bn - 1) / bn, (M + bm - 1) / bm, B);
+
+  std::string kname;
+  kname.reserve(64);
+  bool aligned = N % 64 == 0;
+  std::string type_string = get_type_string(x.dtype());
+  concatenate(
+      kname,
+      mode + (transpose ? "_gather_qmm_t_nax_" : "_gather_qmm_n_nax_"),
+      type_string,
+      "_gs_",
+      group_size,
+      "_b_",
+      bits,
+      "_bm",
+      bm,
+      "_bn",
+      bn,
+      "_bk",
+      bk,
+      "_wm",
+      wm,
+      "_wn",
+      wn,
+      transpose ? (aligned ? "_alN_true" : "_alN_false") : "");
+  MTL::ComputePipelineState* kernel;
+  if (transpose) {
+    kernel = get_quantized_kernel_wrapped(
+        d,
+        kname,
+        "gather_qmm_t_nax_",
+        mode,
+        type_string,
+        group_size,
+        bits,
+        "_bm",
+        bm,
+        "_bn",
+        bn,
+        "_bk",
+        bk,
+        "_wm",
+        wm,
+        "_wn",
+        wn,
+        aligned);
+  } else {
+    kernel = get_quantized_kernel_wrapped(
+        d,
+        kname,
+        "gather_qmm_n_nax_",
+        mode,
+        type_string,
+        group_size,
+        bits,
+        "_bm",
+        bm,
+        "_bn",
+        bn,
+        "_bk",
+        bk,
+        "_wm",
+        wm,
+        "_wn",
+        wn);
+  }
+
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  compute_encoder.set_compute_pipeline_state(kernel);
+
+  int c = 0;
+  compute_encoder.set_input_array(w, c++);
+  compute_encoder.set_input_array(scales, c++);
+  if (biases) {
+    compute_encoder.set_input_array(*biases, c++);
+  }
+  compute_encoder.set_input_array(x, c++);
+  compute_encoder.set_input_array(lhs_indices, c++);
+  compute_encoder.set_input_array(rhs_indices, c++);
+  compute_encoder.set_output_array(out, c++);
+  compute_encoder.set_bytes(K, c++);
+  compute_encoder.set_bytes(N, c++);
+  compute_encoder.set_bytes(M, c++);
+  c = add_strides_and_shapes(compute_encoder, false, x, w, scales, biases, c);
+  add_gather_strides_and_shapes(compute_encoder, lhs_indices, rhs_indices, c);
+
+  compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
+}
+
 void qmm(
     const array& x,
     const array& w,
@@ -466,6 +666,25 @@ void qmm(
     metal::Device& d,
     const Stream& s,
     const std::string& mode) {
+  if (metal::is_nax_available() && transpose && (K % 64 == 0) &&
+      (env::enable_tf32() || x.dtype() != float32)) {
+    return qmm_nax(
+        /* const array& x = */ x,
+        /* const array& w = */ w,
+        /* const array& scales = */ scales,
+        /* const std::optional<array>& biases = */ biases,
+        /* array& out = */ out,
+        /* bool transpose = */ transpose,
+        /* int group_size = */ group_size,
+        /* int bits = */ bits,
+        /* int M = */ M,
+        /* int N = */ N,
+        /* int K = */ K,
+        /* metal::Device& d = */ d,
+        /* const Stream& s = */ s,
+        /* const std::string& mode = */ mode);
+  }
+
   int B = out.size() / M / N;
 
   int wm = 2;
@@ -543,6 +762,27 @@ void gather_qmm(
     metal::Device& d,
     const Stream& s,
     const std::string& mode) {
+  if (metal::is_nax_available() && transpose && (K % 64 == 0) &&
+      (env::enable_tf32() || x.dtype() != float32)) {
+    return gather_qmm_nax(
+        /* const array& x = */ x,
+        /* const array& w = */ w,
+        /* const array& scales = */ scales,
+        /* const std::optional<array>& biases = */ biases,
+        /* const array& lhs_indices = */ lhs_indices,
+        /* const array& rhs_indices = */ rhs_indices,
+        /* array& out = */ out,
+        /* bool transpose = */ transpose,
+        /* int group_size = */ group_size,
+        /* int bits = */ bits,
+        /* int M = */ M,
+        /* int N = */ N,
+        /* int K = */ K,
+        /* metal::Device& d = */ d,
+        /* const Stream& s = */ s,
+        /* const std::string& mode = */ mode);
+  }
+
   int B = out.size() / M / N;
 
   int wm = 2;
@@ -719,6 +959,137 @@ void gather_qvm(
   compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
 }
 
+void gather_qmm_rhs_nax(
+    const array& x_,
+    const array& w_,
+    const array& scales_,
+    const std::optional<array>& biases_,
+    const array& indices_,
+    array& out,
+    bool transpose,
+    int group_size,
+    int bits,
+    int M,
+    int N,
+    int K,
+    metal::Device& d,
+    const Stream& s,
+    const std::string mode) {
+  // Start by normalizing the indices
+  array indices = ensure_row_contiguous(indices_, d, s);
+
+  // Broadcast x with indices. If we are here that means lhs_indices were not
+  // provided so the lhs_indices are implied to be the shape of x broadcasted
+  // with rhs_indices. We need only broadcast x and copy it as if applying the
+  // lhs_indices.
+  auto broadcast_with_indices = [&d, &s, &indices](const array& x) {
+    if (x.size() / x.shape(-2) / x.shape(-1) == indices.size()) {
+      return ensure_row_contiguous(x, d, s);
+    }
+
+    auto x_shape = indices.shape();
+    x_shape.push_back(x.shape(-2));
+    x_shape.push_back(x.shape(-1));
+    array new_x(std::move(x_shape), x.dtype(), nullptr, {});
+    broadcast(x, new_x);
+    return ensure_row_contiguous(new_x, d, s);
+  };
+
+  // Normalize the input arrays
+  array x = broadcast_with_indices(x_);
+  array w = ensure_row_contiguous(w_, d, s);
+  array scales = ensure_row_contiguous(scales_, d, s);
+
+  // TODO: Tune the block sizes
+  int bm = 64, bn = 64, bk = 64;
+  int wm = 2, wn = 2;
+
+  const bool align_M = (M % bm) == 0;
+  const bool align_N = (N % bn) == 0;
+  const bool align_K = (K % bk) == 0;
+
+  // Make the kernel name
+  std::string kname;
+  kname.reserve(64);
+  std::string type_string = get_type_string(x.dtype());
+  concatenate(
+      kname,
+      mode +
+          (transpose ? "_gather_qmm_rhs_nax_nt_" : "_gather_qmm_rhs_nax_nn_"),
+      type_string,
+      "_gs_",
+      group_size,
+      "_b_",
+      bits,
+      "_bm_",
+      bm,
+      "_bn_",
+      bn,
+      "_bk_",
+      bk,
+      "_wm_",
+      wm,
+      "_wn_",
+      wn);
+
+  metal::MTLFCList func_consts = {
+      {&align_M, MTL::DataType::DataTypeBool, 200},
+      {&align_N, MTL::DataType::DataTypeBool, 201},
+      {&align_K, MTL::DataType::DataTypeBool, 202},
+  };
+
+  // And the kernel hash that includes the function constants
+  std::string hash_name;
+  hash_name.reserve(128);
+  concatenate(
+      hash_name,
+      kname,
+      "_align_M_",
+      align_M ? 't' : 'n',
+      "_align_N_",
+      align_N ? 't' : 'n',
+      "_align_K_",
+      align_K ? 't' : 'n');
+
+  // Get and set the kernel
+  auto& compute_encoder = d.get_command_encoder(s.index);
+  auto kernel = get_gather_qmm_kernel(
+      d,
+      kname,
+      hash_name,
+      func_consts,
+      x,
+      group_size,
+      bits,
+      mode,
+      bm,
+      bn,
+      bk,
+      wm,
+      wn,
+      transpose);
+  compute_encoder.set_compute_pipeline_state(kernel);
+
+  MTL::Size group_dims(32, wn, wm);
+  MTL::Size grid_dims((N + bn - 1) / bn, (M + bm - 1) / bm, 1);
+
+  int c = 0;
+  compute_encoder.set_input_array(x, c++);
+  compute_encoder.set_input_array(w, c++);
+  compute_encoder.set_input_array(scales, c++);
+  if (biases_) {
+    array biases = ensure_row_contiguous(*biases_, d, s);
+    compute_encoder.set_input_array(biases, c++);
+  }
+  compute_encoder.set_input_array(indices, c++);
+  compute_encoder.set_output_array(out, c++);
+  compute_encoder.set_bytes(M, c++);
+  compute_encoder.set_bytes(N, c++);
+  compute_encoder.set_bytes(K, c++);
+
+  compute_encoder.dispatch_threadgroups(grid_dims, group_dims);
+}
+
 void gather_qmm_rhs(
     const array& x_,
     const array& w_,
@@ -735,6 +1106,26 @@ void gather_qmm_rhs(
     metal::Device& d,
     const Stream& s,
     const std::string mode) {
+  if (metal::is_nax_available() && transpose &&
+      (env::enable_tf32() || x_.dtype() != float32)) {
+    return gather_qmm_rhs_nax(
+        /* const array& x_ = */ x_,
+        /* const array& w_ = */ w_,
+        /* const array& scales_ = */ scales_,
+        /* const std::optional<array>& biases_ = */ biases_,
+        /* const array& indices_ = */ indices_,
+        /* array& out = */ out,
+        /* bool transpose = */ transpose,
+        /* int group_size = */ group_size,
+        /* int bits = */ bits,
+        /* int M = */ M,
+        /* int N = */ N,
+        /* int K = */ K,
+        /* metal::Device& d = */ d,
+        /* const Stream& s = */ s,
+        /* const std::string mode = */ mode);
+  }
+
   // Start by normalizing the indices
   array indices = ensure_row_contiguous(indices_, d, s);