update install docs and requirements (#2419)

* cuda batched mm

* addmm as well

* comment

.circleci/config.yml

@@ -7,6 +7,9 @@ parameters:
   nightly_build:
     type: boolean
     default: false
+  test_release:
+    type: boolean
+    default: false
 
 jobs:
   build_documentation:
@@ -200,8 +203,12 @@ jobs:
               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-12:2023.11.1
+      image: "linux-cuda-12:<< parameters.image_date >>"
       resource_class: gpu.nvidia.small.gen2
     steps:
       - checkout
@@ -209,6 +216,7 @@ jobs:
           name: Install Python package
           command: |
             sudo apt-get update
+            sudo apt-get install libcudnn9-dev-cuda-12
             sudo apt-get install libblas-dev liblapack-dev liblapacke-dev
             python3 -m venv env
             source env/bin/activate
@@ -366,22 +374,27 @@ jobs:
         type: string
         default: ""
     machine:
-      image: linux-cuda-12:default
+      image: ubuntu-2204:current
-      resource_class: gpu.nvidia.small.gen2
+      resource_class: large
     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
-            python -m venv env
-            source env/bin/activate
             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
@@ -392,7 +405,6 @@ jobs:
             - run:
                 name: Upload package
                 command: |
-                  source env/bin/activate
                   twine upload wheelhouse/*.whl
       - store_artifacts:
           path: wheelhouse/
@@ -405,19 +417,24 @@ workflows:
             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", "14.0"]
       - linux_build_and_test
-      - cuda_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:
@@ -601,3 +618,87 @@ workflows:
             parameters:
               python_version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
       - build_cuda_release
+
+  build_dev_release:
+    when:
+      and:
+        - equal: [ main, << pipeline.git.branch >> ]
+        - << pipeline.parameters.test_release >>
+    jobs:
+      - build_release:
+          matrix:
+            parameters:
+              python_version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+              macosx_deployment_target: ["13.5", "14.0", "15.0"]
+              build_env: ["DEV_RELEASE=1"]
+              xcode_version: ["16.2.0", "15.0.0"]
+            exclude:
+              - macosx_deployment_target: "13.5"
+                xcode_version: "16.2.0"
+                python_version: "3.9"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "13.5"
+                xcode_version: "16.2.0"
+                python_version: "3.10"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "13.5"
+                xcode_version: "16.2.0"
+                python_version: "3.11"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "13.5"
+                xcode_version: "16.2.0"
+                python_version: "3.12"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "13.5"
+                xcode_version: "16.2.0"
+                python_version: "3.13"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "14.0"
+                xcode_version: "15.0.0"
+                python_version: "3.9"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "14.0"
+                xcode_version: "15.0.0"
+                python_version: "3.10"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "14.0"
+                xcode_version: "15.0.0"
+                python_version: "3.11"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "14.0"
+                xcode_version: "15.0.0"
+                python_version: "3.12"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "14.0"
+                xcode_version: "15.0.0"
+                python_version: "3.13"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "15.0"
+                xcode_version: "15.0.0"
+                python_version: "3.9"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "15.0"
+                xcode_version: "15.0.0"
+                python_version: "3.10"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "15.0"
+                xcode_version: "15.0.0"
+                python_version: "3.11"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "15.0"
+                xcode_version: "15.0.0"
+                python_version: "3.12"
+                build_env: "DEV_RELEASE=1"
+              - macosx_deployment_target: "15.0"
+                xcode_version: "15.0.0"
+                python_version: "3.13"
+                build_env: "DEV_RELEASE=1"
+      - build_linux_release:
+          matrix:
+            parameters:
+              python_version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+              build_env: ["DEV_RELEASE=1"]
+      - build_cuda_release:
+          matrix:
+            parameters:
+              build_env: ["DEV_RELEASE=1"]

README.md

@@ -11,10 +11,10 @@ brought to you by Apple machine learning research.
 
 Some key features of MLX include:
 
- - **Familiar APIs**: MLX has a Python API that closely follows NumPy.  MLX
+ - **Familiar APIs**: MLX has a Python API that closely follows NumPy. MLX
    also has fully featured C++, [C](https://github.com/ml-explore/mlx-c), and
    [Swift](https://github.com/ml-explore/mlx-swift/) APIs, which closely mirror
-   the Python API.  MLX has higher-level packages like `mlx.nn` and
+   the Python API. MLX has higher-level packages like `mlx.nn` and
    `mlx.optimizers` with APIs that closely follow PyTorch to simplify building
    more complex models.
 
@@ -68,18 +68,23 @@ in the documentation.
 
 ## Installation
 
-MLX is available on [PyPI](https://pypi.org/project/mlx/). To install the Python API, run:
+MLX is available on [PyPI](https://pypi.org/project/mlx/). To install MLX on
+macOS, run:
 
-**With `pip`**:
+```bash
-
-```
 pip install mlx
 ```
 
-**With `conda`**:
+To install the CUDA backend on Linux, run:
 
+```bash
+pip install "mlx[cuda]"
 ```
-conda install -c conda-forge mlx
+
+To install a CPU-only Linux package, run:
+
+```bash
+pip install "mlx[cpu]"
 ```
 
 Checkout the

docs/src/install.rst

@@ -13,7 +13,7 @@ silicon computer is
 
     pip install mlx
 
-To install from PyPI you must meet the following requirements:
+To install from PyPI your system must meet the following requirements:
 
 - Using an M series chip (Apple silicon)
 - Using a native Python >= 3.9
@@ -26,13 +26,22 @@ To install from PyPI you must meet the following requirements:
 CUDA
 ^^^^
 
-MLX has a CUDA backend which you can use on any Linux platform with CUDA 12
+MLX has a CUDA backend which you can install with:
-and SM 7.0 (Volta) and up. To install MLX with CUDA support, run:
 
 .. code-block:: shell
 
     pip install "mlx[cuda]"
 
+To install the CUDA package from PyPi your system must meet the following
+requirements:
+
+- Nvidia architecture >= SM 7.0 (Volta)
+- Nvidia driver >= 550.54.14
+- CUDA toolkit >= 12.0
+- Linux distribution with glibc >= 2.35
+- Python >= 3.9
+
+
 CPU-only (Linux)
 ^^^^^^^^^^^^^^^^
 
@@ -42,6 +51,13 @@ For a CPU-only version of MLX that runs on Linux use:
 
     pip install "mlx[cpu]"
 
+To install the CPU-only package from PyPi your system must meet the following
+requirements:
+
+- Linux distribution with glibc >= 2.35
+- Python >= 3.9
+
+
 Troubleshooting
 ^^^^^^^^^^^^^^^
 

mlx/backend/cpu/copy.cpp

@@ -377,4 +377,10 @@ void copy_cpu_inplace(
       });
 }
 
+array contiguous_copy_cpu(const array& arr, Stream stream) {
+  array arr_copy(arr.shape(), arr.dtype(), nullptr, {});
+  copy_cpu(arr, arr_copy, CopyType::General, stream);
+  return arr_copy;
+}
+
 } // namespace mlx::core

mlx/backend/cpu/copy.h

@@ -30,4 +30,7 @@ void copy_cpu_inplace(
     const std::optional<array>& dynamic_i_offset = std::nullopt,
     const std::optional<array>& dynamic_o_offset = std::nullopt);
 
+// Return a contiguous array with same shape that copies the data of |arr|.
+array contiguous_copy_cpu(const array& arr, Stream stream);
+
 } // namespace mlx::core

mlx/backend/cpu/distributed.cpp

@@ -13,9 +13,7 @@ std::pair<array, bool> ensure_row_contiguous(const array& arr, Stream stream) {
   if (arr.flags().row_contiguous) {
     return {arr, false};
   } else {
-    array arr_copy(arr.shape(), arr.dtype(), nullptr, {});
+    return {contiguous_copy_cpu(arr, stream), true};
-    copy_cpu(arr, arr_copy, CopyType::General, stream);
-    return {arr_copy, true};
   }
 };
 
@@ -34,8 +32,7 @@ void AllReduce::eval_cpu(
       }
       return in;
     } else {
-      array arr_copy(in.shape(), in.dtype(), nullptr, {});
+      array arr_copy = contiguous_copy_cpu(in, s);
-      copy_cpu(in, arr_copy, CopyType::General, s);
       out.copy_shared_buffer(arr_copy);
       return arr_copy;
     }

mlx/backend/cpu/logsumexp.cpp

@@ -87,8 +87,7 @@ void LogSumExp::eval_cpu(const std::vector<array>& inputs, array& out) {
     if (x.flags().contiguous && x.strides()[x.ndim() - 1] == 1) {
       return x;
     } else {
-      auto x_copy = array(x.shape(), x.dtype(), nullptr, {});
+      array x_copy = contiguous_copy_cpu(x, s);
-      copy_cpu(x, x_copy, CopyType::General, s);
       encoder.add_temporary(x_copy);
       return x_copy;
     }

mlx/backend/cpu/masked_mm.cpp

@@ -136,9 +136,8 @@ void BlockMaskedMM::eval_cpu(const std::vector<array>& inputs, array& out) {
           }
           return std::make_tuple(true, sty, arr, false);
         } else {
-          array arr_copy(arr.shape(), arr.dtype(), nullptr, {});
-          copy_cpu(arr, arr_copy, CopyType::General, s);
           int64_t stx = arr.shape(-1);
+          array arr_copy = contiguous_copy_cpu(arr, s);
           return std::make_tuple(false, stx, arr_copy, true);
         }
       };

mlx/backend/cpu/quantized.cpp

@@ -712,9 +712,7 @@ void fast::AffineQuantize::eval_cpu(
     if (arr.flags().row_contiguous) {
       return std::make_pair(arr, false);
     } else {
-      array arr_copy(arr.shape(), arr.dtype(), nullptr, {});
+      return std::make_pair(contiguous_copy_cpu(arr, s), true);
-      copy_cpu(arr, arr_copy, CopyType::General, s);
-      return std::make_pair(arr_copy, true);
     }
   };
 

mlx/backend/cpu/scan.cpp

@@ -250,10 +250,8 @@ void Scan::eval_cpu(const std::vector<array>& inputs, array& out) {
   // Ensure contiguity
   auto in = inputs[0];
   if (!in.flags().row_contiguous) {
-    array arr_copy(in.shape(), in.dtype(), nullptr, {});
+    in = contiguous_copy_cpu(in, stream());
-    copy_cpu(in, arr_copy, CopyType::General, stream());
+    encoder.add_temporary(in);
-    in = arr_copy;
-    encoder.add_temporary(arr_copy);
   }
   out.set_data(allocator::malloc(out.nbytes()));
 

mlx/backend/cpu/softmax.cpp

@@ -131,8 +131,7 @@ void Softmax::eval_cpu(const std::vector<array>& inputs, array& out) {
       }
       return x;
     } else {
-      array x_copy(x.shape(), x.dtype(), nullptr, {});
+      array x_copy = contiguous_copy_cpu(x, s);
-      copy_cpu(x, x_copy, CopyType::General, s);
       out.copy_shared_buffer(x_copy);
       return x_copy;
     }

mlx/backend/cuda/CMakeLists.txt

@@ -15,11 +15,14 @@ target_sources(
           ${CMAKE_CURRENT_SOURCE_DIR}/copy/copy_general.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/copy/copy_general_dynamic.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/copy/copy_general_input.cu
+          ${CMAKE_CURRENT_SOURCE_DIR}/conv.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/cuda.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/device.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/eval.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/event.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/fence.cpp
+          ${CMAKE_CURRENT_SOURCE_DIR}/gemms/gemv.cu
+          ${CMAKE_CURRENT_SOURCE_DIR}/gemms/cublas_gemm.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/jit_module.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/indexing.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/kernel_utils.cu
@@ -45,6 +48,14 @@ target_sources(
           ${CMAKE_CURRENT_SOURCE_DIR}/quantized.cu
           ${CMAKE_CURRENT_SOURCE_DIR}/worker.cpp)
 
+if(CMAKE_CUDA_COMPILER_VERSION VERSION_GREATER_EQUAL 12.9.0)
+  target_sources(
+    mlx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/gemms/cublas_batched_gemm_12_9.cu)
+else()
+  target_sources(
+    mlx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/gemms/cublas_batched_gemm_12_0.cpp)
+endif()
+
 target_compile_definitions(mlx PRIVATE MLX_USE_CUDA)
 
 # Embed kernel sources in binary for JIT compilation.
@@ -87,6 +98,13 @@ endif()
 target_compile_options(
   mlx PRIVATE "$<$<COMPILE_LANGUAGE:CUDA>:--Wno-deprecated-gpu-targets>")
 
+# Use stronger binaries compression. This feature was introduced in CUDA 12.8
+# and requires drivers released after CUDA 12.4.
+if(CMAKE_CUDA_COMPILER_VERSION VERSION_GREATER_EQUAL 12.8.0)
+  target_compile_options(
+    mlx PRIVATE "$<$<COMPILE_LANGUAGE:CUDA>:--compress-mode=size>")
+endif()
+
 # Compute capability 7 is required for synchronization between CPU/GPU with
 # managed memory. TODO: Add more architectures for potential performance gain.
 set(MLX_CUDA_ARCHITECTURES
@@ -123,6 +141,23 @@ target_link_libraries(mlx PRIVATE CUDA::cublasLt)
 # Use NVRTC and driver APIs.
 target_link_libraries(mlx PRIVATE CUDA::nvrtc CUDA::cuda_driver)
 
+# Use the frontend APIs of cuDNN.
+FetchContent_Declare(
+  cudnn
+  GIT_REPOSITORY https://github.com/NVIDIA/cudnn-frontend.git
+  GIT_TAG v1.12.1
+  GIT_SHALLOW TRUE
+  EXCLUDE_FROM_ALL)
+set(CUDNN_FRONTEND_SKIP_JSON_LIB ON)
+set(CUDNN_FRONTEND_BUILD_SAMPLES OFF)
+set(CUDNN_FRONTEND_BUILD_TESTS OFF)
+set(CUDNN_FRONTEND_BUILD_PYTHON_BINDINGS OFF)
+FetchContent_MakeAvailable(cudnn)
+target_link_libraries(mlx PRIVATE cudnn_frontend)
+# Link with the actual cuDNN libraries.
+include(${cudnn_frontend_SOURCE_DIR}/cmake/cuDNN.cmake)
+target_link_libraries(mlx PRIVATE CUDNN::cudnn_all)
+
 # Suppress nvcc warnings on MLX headers.
 target_compile_options(mlx PRIVATE $<$<COMPILE_LANGUAGE:CUDA>:-Xcudafe
                                    --diag_suppress=997>)

mlx/backend/cuda/allocator.cpp

@@ -2,7 +2,6 @@
 
 #include "mlx/backend/cuda/allocator.h"
 #include "mlx/backend/cuda/utils.h"
-#include "mlx/backend/cuda/worker.h"
 #include "mlx/utils.h"
 
 #include <cuda_runtime.h>
@@ -17,14 +16,66 @@ namespace cu {
 
 constexpr int page_size = 16384;
 
+// Any allocations smaller than this will try to use the small pool
+constexpr int small_block_size = 8;
+
+// The small pool size in bytes. This should be a multiple of the host page
+// size and small_block_size.
+constexpr int small_pool_size = 4 * page_size;
+
+SmallSizePool::SmallSizePool() {
+  auto num_blocks = small_pool_size / small_block_size;
+  buffer_ = new Block[num_blocks];
+
+  next_free_ = buffer_;
+
+  CHECK_CUDA_ERROR(cudaMallocManaged(&data_, small_pool_size));
+  CHECK_CUDA_ERROR(
+      cudaMemAdvise(data_, small_pool_size, cudaMemAdviseSetReadMostly, 0));
+
+  auto curr = next_free_;
+  for (size_t i = 1; i < num_blocks; ++i) {
+    curr->next = buffer_ + i;
+    curr = curr->next;
+  }
+  curr->next = nullptr;
+}
+
+SmallSizePool::~SmallSizePool() {
+  CHECK_CUDA_ERROR(cudaFree(data_));
+  delete[] buffer_;
+}
+
+CudaBuffer* SmallSizePool::malloc() {
+  if (next_free_ == nullptr) {
+    return nullptr;
+  }
+  Block* b = next_free_;
+  uint64_t i = next_free_ - buffer_;
+  next_free_ = next_free_->next;
+  b->buf.data = static_cast<char*>(data_) + i * small_block_size;
+  b->buf.size = small_block_size;
+  return &b->buf;
+}
+
+void SmallSizePool::free(CudaBuffer* buf) {
+  auto b = reinterpret_cast<Block*>(buf);
+  b->next = next_free_;
+  next_free_ = b;
+}
+
+bool SmallSizePool::in_pool(CudaBuffer* buf) {
+  constexpr int num_blocks = (small_pool_size / small_block_size);
+  auto b = reinterpret_cast<Block*>(buf);
+  int64_t block_num = b - buffer_;
+  return block_num >= 0 && block_num < num_blocks;
+}
+
 CudaAllocator::CudaAllocator()
     : buffer_cache_(
           page_size,
           [](CudaBuffer* buf) { return buf->size; },
-          [this](CudaBuffer* buf) {
+          [this](CudaBuffer* buf) { cuda_free(buf); }) {
-            cuda_free(buf->data);
-            delete buf;
-          }) {
   // TODO: Set memory limit for multi-device.
   size_t free, total;
   CHECK_CUDA_ERROR(cudaMemGetInfo(&free, &total));
@@ -36,7 +87,9 @@ Buffer CudaAllocator::malloc(size_t size) {
   // Find available buffer from cache.
   auto orig_size = size;
   std::unique_lock lock(mutex_);
-  if (size < page_size) {
+  if (size <= small_block_size) {
+    size = 8;
+  } else if (size < page_size) {
     size = next_power_of_2(size);
   } else {
     size = page_size * ((size + page_size - 1) / page_size);
@@ -44,19 +97,25 @@ Buffer CudaAllocator::malloc(size_t size) {
 
   CudaBuffer* buf = buffer_cache_.reuse_from_cache(size);
   if (!buf) {
-    // If we have a lot of memory pressure or are over the maximum cache size,
+    // If we have a lot of memory pressure try to reclaim memory from the cache.
-    // try to reclaim memory from the cache.
+    int64_t mem_to_free =
-    size_t mem_required = get_active_memory() + get_cache_memory() + size;
+        get_active_memory() + get_cache_memory() + size - memory_limit_;
-    if (mem_required >= memory_limit_) {
+    if (mem_to_free > 0) {
-      buffer_cache_.release_cached_buffers(mem_required - memory_limit_);
+      buffer_cache_.release_cached_buffers(mem_to_free);
     }
 
+    // Try the scalar pool first
+    if (size <= small_block_size) {
+      buf = scalar_pool_.malloc();
+    }
     lock.unlock();
-    buf = new CudaBuffer{nullptr, size};
+    if (!buf) {
-    cudaError_t err = cudaMallocManaged(&buf->data, size);
+      buf = new CudaBuffer{nullptr, size};
-    if (err != cudaSuccess && err != cudaErrorMemoryAllocation) {
+      cudaError_t err = cudaMallocManaged(&buf->data, size);
-      throw std::runtime_error(fmt::format(
+      if (err != cudaSuccess && err != cudaErrorMemoryAllocation) {
-          "cudaMallocManaged failed: {}.", cudaGetErrorString(err)));
+        throw std::runtime_error(fmt::format(
+            "cudaMallocManaged failed: {}.", cudaGetErrorString(err)));
+      }
     }
     lock.lock();
   }
@@ -67,7 +126,6 @@ Buffer CudaAllocator::malloc(size_t size) {
   if (get_cache_memory() > max_pool_size_) {
     buffer_cache_.release_cached_buffers(get_cache_memory() - max_pool_size_);
   }
-
   return Buffer{buf};
 }
 
@@ -82,9 +140,7 @@ void CudaAllocator::free(Buffer buffer) {
   if (get_cache_memory() < max_pool_size_) {
     buffer_cache_.recycle_to_cache(buf);
   } else {
-    lock.unlock();
+    cuda_free(buf);
-    cuda_free(buf->data);
-    delete buf;
   }
 }
 
@@ -96,27 +152,14 @@ size_t CudaAllocator::size(Buffer buffer) const {
   return buf->size;
 }
 
-void CudaAllocator::register_this_thread() {
+// This must be called with mutex_ aquired
-  std::lock_guard lock(worker_mutex_);
+void CudaAllocator::cuda_free(CudaBuffer* buf) {
-  allowed_threads_.insert(std::this_thread::get_id());
+  if (scalar_pool_.in_pool(buf)) {
-}
+    scalar_pool_.free(buf);
-
+  } else {
-void CudaAllocator::cuda_free(void* buf) {
+    cudaFree(buf->data);
-  // If cuda_free() is called from a unregistered thread, reschedule the call to
+    delete buf;
-  // worker.
-  {
-    std::lock_guard lock(worker_mutex_);
-    if (allowed_threads_.count(std::this_thread::get_id()) == 0) {
-      if (!worker_) {
-        worker_.reset(new Worker);
-      }
-      worker_->add_task([this, buf]() { this->cuda_free(buf); });
-      worker_->end_batch();
-      worker_->commit();
-      return;
-    }
   }
-  cudaFree(buf);
 }
 
 size_t CudaAllocator::get_active_memory() const {

mlx/backend/cuda/allocator.h

@@ -7,13 +7,10 @@
 
 #include <mutex>
 #include <set>
-#include <thread>
 #include <utility>
 
 namespace mlx::core::cu {
 
-class Worker;
-
 using allocator::Buffer;
 
 // Stores cuda-managed unified memory.
@@ -22,21 +19,35 @@ struct CudaBuffer {
   size_t size;
 };
 
+class SmallSizePool {
+ private:
+  union Block {
+    Block* next;
+    CudaBuffer buf;
+  };
+
+  Block* buffer_{nullptr};
+  void* data_{nullptr};
+  Block* next_free_{nullptr};
+
+ public:
+  SmallSizePool();
+  ~SmallSizePool();
+
+  SmallSizePool(const SmallSizePool&) = delete;
+  SmallSizePool& operator=(const SmallSizePool&) = delete;
+
+  CudaBuffer* malloc();
+  void free(CudaBuffer* buf);
+  bool in_pool(CudaBuffer* buf);
+};
+
 class CudaAllocator : public allocator::Allocator {
  public:
   Buffer malloc(size_t size) override;
   void free(Buffer buffer) override;
   size_t size(Buffer buffer) const override;
 
-  // Register current thread as safe to free buffers.
-  // In cuda freeing a buffer implicitly synchronizes stream, and for threads
-  // that may be waited by gpu stream (for example cpu stream threads), freeing
-  // buffers there would result in dead lock.
-  void register_this_thread();
-
-  // Call cudaFree in the safe thread.
-  void cuda_free(void* buf);
-
   size_t get_active_memory() const;
   size_t get_peak_memory() const;
   void reset_peak_memory();
@@ -47,19 +58,18 @@ class CudaAllocator : public allocator::Allocator {
   void clear_cache();
 
  private:
+  void cuda_free(CudaBuffer* buf);
+
   CudaAllocator();
   friend CudaAllocator& allocator();
 
-  std::mutex worker_mutex_;
-  std::unique_ptr<Worker> worker_;
-  std::set<std::thread::id> allowed_threads_;
-
   std::mutex mutex_;
   size_t memory_limit_;
   size_t max_pool_size_;
   BufferCache<CudaBuffer> buffer_cache_;
   size_t active_memory_{0};
   size_t peak_memory_{0};
+  SmallSizePool scalar_pool_;
 };
 
 CudaAllocator& allocator();

mlx/backend/cuda/arg_reduce.cu

@@ -1,8 +1,8 @@
 // Copyright © 2025 Apple Inc.
+
 #include "mlx/backend/common/utils.h"
 #include "mlx/backend/cuda/device.h"
 #include "mlx/backend/cuda/device/fp16_math.cuh"
-#include "mlx/backend/cuda/iterators/strided_iterator.cuh"
 #include "mlx/backend/cuda/kernel_utils.cuh"
 #include "mlx/dtype_utils.h"
 #include "mlx/primitives.h"
@@ -115,7 +115,7 @@ __global__ void arg_reduce_general(
     T vals[N_READS];
     auto tid = r * BLOCK_DIM + block.thread_index().x;
     cub::LoadDirectBlocked(
-        tid, strided_iterator(in + in_idx, axis_stride), vals, axis_size, init);
+        tid, StridedIterator(in + in_idx, axis_stride), vals, axis_size, init);
     best = op.reduce_many(best, vals, tid * N_READS);
   }
 

mlx/backend/cuda/binary.cu

@@ -128,7 +128,7 @@ __global__ void binary_g(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto [a_idx, b_idx] = elem_to_loc_4d(
+    auto [a_idx, b_idx] = elem_to_loc(
         index, shape.data(), a_strides.data(), b_strides.data(), ndim);
     out[index] = Op{}(a[a_idx], b[b_idx]);
   }

mlx/backend/cuda/binary_two.cu

@@ -160,7 +160,7 @@ __global__ void binary_two_g(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto [a_idx, b_idx] = elem_to_loc_4d(
+    auto [a_idx, b_idx] = elem_to_loc(
         index, shape.data(), a_strides.data(), b_strides.data(), ndim);
     auto out = Op{}(a[a_idx], b[b_idx]);
     out_a[index] = out[0];

mlx/backend/cuda/conv.cpp

@@ -0,0 +1,340 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/device.h"
+#include "mlx/backend/cuda/device/config.h"
+#include "mlx/backend/cuda/lru_cache.h"
+#include "mlx/backend/gpu/copy.h"
+#include "mlx/dtype_utils.h"
+#include "mlx/primitives.h"
+
+// cudnn_frontend.h redefines this macro.
+#undef CHECK_CUDA_ERROR
+
+#include <cudnn_frontend.h>
+#include <cudnn_frontend_find_plan.h>
+#include <fmt/format.h>
+#include <nvtx3/nvtx3.hpp>
+
+#include <cassert>
+#include <numeric>
+
+namespace mlx::core {
+
+namespace {
+
+// Not all engines support it so can not use this API now.
+#define MLX_USE_CUDNN_NATIVE_CUDA_GRAPH_API 0
+
+struct ConvCacheKey {
+  int device_id;
+  cudnnBackendDescriptorType_t backend_type;
+  cudnnDataType_t cudnn_type;
+  std::array<int, MAX_NDIM> input_shape;
+  std::array<int, MAX_NDIM> filter_shape;
+  std::array<int, MAX_NDIM> padding_lo;
+  std::array<int, MAX_NDIM> padding_hi;
+  std::array<int, MAX_NDIM> stride;
+  std::array<int, MAX_NDIM> dilation;
+  int groups;
+  uint8_t input_alignment;
+  uint8_t filter_alignment;
+  uint8_t output_alignment;
+};
+
+auto& conv_cache() {
+  static LRUBytesKeyCache<ConvCacheKey, cudnn_frontend::ExecutionPlan> cache(
+      /* capacity */ 128);
+  return cache;
+}
+
+template <typename T, typename U>
+inline std::vector<T> convert_vector(const std::vector<U>& vec) {
+  return std::vector<T>(vec.begin(), vec.end());
+}
+
+template <typename T>
+inline std::array<T, MAX_NDIM> fixed_vector(const std::vector<T>& vec) {
+  if (vec.size() > MAX_NDIM) {
+    throw std::runtime_error(
+        fmt::format("ndim can not be larger than {}.", MAX_NDIM));
+  }
+  std::array<T, MAX_NDIM> result = {};
+  std::copy_n(vec.begin(), vec.size(), result.begin());
+  return result;
+}
+
+auto nhwc_to_nchw(const array& x) {
+  auto shape = convert_vector<int64_t>(x.shape());
+  shape.insert(shape.begin() + 1, shape.back());
+  shape.erase(shape.end() - 1);
+  auto strides = convert_vector<int64_t>(x.strides());
+  strides.insert(strides.begin() + 1, strides.back());
+  strides.erase(strides.end() - 1);
+  return std::make_tuple(shape, strides);
+}
+
+inline cudnnDataType_t dtype_to_cudnn_type(Dtype dtype) {
+  switch (dtype) {
+    case int8:
+      return CUDNN_DATA_INT8;
+    case int32:
+      return CUDNN_DATA_INT32;
+    case uint8:
+      return CUDNN_DATA_UINT8;
+    case float16:
+      return CUDNN_DATA_HALF;
+    case bfloat16:
+      return CUDNN_DATA_BFLOAT16;
+    case float32:
+      return CUDNN_DATA_FLOAT;
+    case float64:
+      return CUDNN_DATA_DOUBLE;
+    default:
+      throw std::runtime_error(fmt::format(
+          "Unsupported dtype in Convolution: {}.", dtype_to_string(dtype)));
+  }
+}
+
+inline uint8_t get_alignment(const array& x) {
+  uint8_t alignment = 1;
+  uintptr_t address = reinterpret_cast<uintptr_t>(x.data<void>());
+  for (; alignment < 32; alignment *= 2) {
+    if (address % (alignment * 2)) {
+      return alignment;
+    }
+  }
+  return alignment;
+}
+
+inline cudnn_frontend::Tensor build_tensor(int64_t id, const array& x) {
+  auto [shape, strides] = nhwc_to_nchw(x);
+  return cudnn_frontend::TensorBuilder()
+      .setDim(shape.size(), shape.data())
+      .setStrides(strides.size(), strides.data())
+      .setId(id)
+      .setAlignment(get_alignment(x))
+      .setDataType(dtype_to_cudnn_type(x.dtype()))
+      .build();
+}
+
+cudnn_frontend::EngineConfigList get_engine_configs(
+    cudnnBackendDescriptorType_t backend_type,
+    Dtype dtype,
+    cudnn_frontend::OperationGraph& op_graph,
+    bool use_fallback = false) {
+  cudnn_frontend::GeneratorSource source;
+  if (use_fallback) {
+    source = [&backend_type](cudnn_frontend::OperationGraph& op_graph) {
+      auto fallback = cudnn_frontend::EngineFallbackListBuilder()
+                          .setOperationGraph(op_graph)
+                          .setOperation(backend_type)
+                          .build();
+      return fallback.getFallbackList();
+    };
+  } else {
+    source = [](cudnn_frontend::OperationGraph& op_graph) {
+      auto heuristics = cudnn_frontend::EngineHeuristicsBuilder()
+                            .setOperationGraph(op_graph)
+                            .setHeurMode(CUDNN_HEUR_MODE_A)
+                            .build();
+      return heuristics.getEngineConfig(heuristics.getEngineConfigCount());
+    };
+  }
+
+  cudnn_frontend::EngineConfigGenerator generator(1, &source);
+  auto configs = generator.generate_engine_config(op_graph);
+
+  cudnn_frontend::EngineConfigList filtered_configs;
+  cudnn_frontend::filter(configs, filtered_configs, [dtype](auto c) {
+    if (cudnn_frontend::hasNumericalNote<
+            CUDNN_NUMERICAL_NOTE_DOWN_CONVERT_INPUTS>(c)) {
+      return true;
+    }
+    if (cudnn_frontend::hasNumericalNote<CUDNN_NUMERICAL_NOTE_TENSOR_CORE>(c) &&
+        dtype == float32 && !env::enable_tf32()) {
+      return true;
+    }
+    return false;
+  });
+  return filtered_configs;
+}
+
+bool execute_plan(
+    cu::CommandEncoder& encoder,
+    cudnn_frontend::ExecutionPlan& plan,
+    const array& in,
+    const array& wt,
+    array& out) {
+  int workspace_size = plan.getWorkspaceSize();
+  array workspace(allocator::malloc(workspace_size), {workspace_size}, uint8);
+
+  int64_t uids[3] = {'x', 'w', 'y'};
+  void* data_ptrs[3] = {
+      const_cast<void*>(in.data<void>()),
+      const_cast<void*>(wt.data<void>()),
+      out.data<void>(),
+  };
+
+  auto variantPack = cudnn_frontend::VariantPackBuilder()
+                         .setWorkspacePointer(workspace.data<void>())
+                         .setDataPointers(3, data_ptrs)
+                         .setUids(3, uids)
+                         .build();
+
+  auto handle = encoder.device().cudnn_handle();
+  cudnnSetStream(handle, encoder.stream());
+
+#if CUDNN_VERSION >= 90500 && MLX_USE_CUDNN_NATIVE_CUDA_GRAPH_API
+  cudaGraph_t graph;
+  cudaGraphCreate(&graph, 0);
+  std::unique_ptr<cudaGraph_t, void (*)(cudaGraph_t*)> graph_freer(
+      &graph, [](cudaGraph_t* p) { cudaGraphDestroy(*p); });
+  if (cudnnBackendPopulateCudaGraph(
+          handle, plan.get_raw_desc(), variantPack.get_raw_desc(), graph) !=
+      CUDNN_STATUS_SUCCESS) {
+    return false;
+  }
+  encoder.add_graph_node(graph);
+#else
+  auto capture = encoder.capture_context();
+  if (cudnnBackendExecute(
+          handle, plan.get_raw_desc(), variantPack.get_raw_desc()) !=
+      CUDNN_STATUS_SUCCESS) {
+    // Discard the captured graph when failed.
+    capture.discard = true;
+    return false;
+  }
+#endif
+
+  encoder.add_temporary(workspace);
+  return true;
+}
+
+bool try_engines(
+    cu::CommandEncoder& encoder,
+    cudnn_frontend::EngineConfigList& configs,
+    const ConvCacheKey& cache_key,
+    const std::string& op_graph_tag,
+    const array& in,
+    const array& wt,
+    array& out) {
+  for (auto& config : configs) {
+    try {
+      auto plan = cudnn_frontend::ExecutionPlanBuilder()
+                      .setHandle(encoder.device().cudnn_handle())
+                      .setEngineConfig(config, op_graph_tag)
+                      .build();
+      if (execute_plan(encoder, plan, in, wt, out)) {
+        conv_cache().emplace(cache_key, std::move(plan));
+        return true;
+      }
+    } catch (cudnn_frontend::cudnnException&) {
+    }
+  }
+  return false;
+}
+
+} // namespace
+
+void Convolution::eval_gpu(const std::vector<array>& inputs, array& out) {
+  nvtx3::scoped_range r("Convolution::eval_gpu");
+  if (out.size() == 0) {
+    return;
+  }
+
+  assert(inputs.size() == 2);
+  array in = inputs[0];
+  array wt = inputs[1];
+  out.set_data(allocator::malloc(out.nbytes()));
+
+  auto& s = stream();
+  auto& encoder = cu::get_command_encoder(s);
+
+  // cuDNN requires contiguous input.
+  // TODO: Handle NCHW format specially.
+  if (!in.flags().row_contiguous) {
+    in = contiguous_copy_gpu(in, s);
+    encoder.add_temporary(in);
+  }
+  if (!wt.flags().row_contiguous) {
+    wt = contiguous_copy_gpu(wt, s);
+    encoder.add_temporary(wt);
+  }
+
+  encoder.set_input_array(in);
+  encoder.set_input_array(wt);
+  encoder.set_output_array(out);
+
+  auto backend_type = CUDNN_BACKEND_OPERATION_CONVOLUTION_FORWARD_DESCRIPTOR;
+  auto cudnn_type = dtype_to_cudnn_type(in.dtype());
+
+  // Search cache.
+  ConvCacheKey cache_key{
+      encoder.device().cuda_device(),
+      backend_type,
+      cudnn_type,
+      fixed_vector(in.shape()),
+      fixed_vector(wt.shape()),
+      fixed_vector(padding_lo_),
+      fixed_vector(padding_hi_),
+      fixed_vector(kernel_strides_),
+      fixed_vector(kernel_dilation_),
+      groups_,
+      get_alignment(in),
+      get_alignment(wt),
+      get_alignment(out)};
+  if (auto it = conv_cache().find(cache_key); it != conv_cache().end()) {
+    if (!execute_plan(encoder, it->second, in, wt, out)) {
+      throw std::runtime_error("Cached convolution plan failed to execute.");
+    }
+    return;
+  }
+
+  // Build operation graph.
+  auto compute_data_type = (in.dtype() == float16 || in.dtype() == bfloat16)
+      ? CUDNN_DATA_FLOAT
+      : cudnn_type;
+
+  auto stride = convert_vector<int64_t>(kernel_strides_);
+  auto padding_lo = convert_vector<int64_t>(padding_lo_);
+  auto padding_hi = convert_vector<int64_t>(padding_hi_);
+  auto dilation = convert_vector<int64_t>(kernel_dilation_);
+
+  auto conv_desc = cudnn_frontend::ConvDescBuilder()
+                       .setDataType(compute_data_type)
+                       .setMathMode(CUDNN_CROSS_CORRELATION)
+                       .setNDims(stride.size())
+                       .setStrides(stride.size(), stride.data())
+                       .setPrePadding(padding_lo.size(), padding_lo.data())
+                       .setPostPadding(padding_hi.size(), padding_hi.data())
+                       .setDilation(dilation.size(), dilation.data())
+                       .build();
+
+  auto op = cudnn_frontend::OperationBuilder(backend_type)
+                .setxDesc(build_tensor('x', in))
+                .setwDesc(build_tensor('w', wt))
+                .setyDesc(build_tensor('y', out))
+                .setcDesc(conv_desc)
+                .build();
+
+  std::array<cudnn_frontend::Operation const*, 1> ops = {&op};
+  auto op_graph = cudnn_frontend::OperationGraphBuilder()
+                      .setHandle(encoder.device().cudnn_handle())
+                      .setOperationGraph(ops.size(), ops.data())
+                      .build();
+
+  // Try to run plans based on heuristics.
+  auto configs = get_engine_configs(backend_type, in.dtype(), op_graph);
+  auto op_graph_tag = op_graph.getTag();
+  if (try_engines(encoder, configs, cache_key, op_graph_tag, in, wt, out)) {
+    return;
+  }
+  // Then try fallback plans.
+  configs = get_engine_configs(backend_type, in.dtype(), op_graph);
+  if (try_engines(encoder, configs, cache_key, op_graph_tag, in, wt, out)) {
+    return;
+  }
+  throw std::runtime_error("Unable to find an engine for convolution.");
+}
+
+} // namespace mlx::core

mlx/backend/cuda/copy/copy_general.cu

@@ -37,7 +37,7 @@ __global__ void copy_gg(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto [idx_in, idx_out] = elem_to_loc_4d(
+    auto [idx_in, idx_out] = elem_to_loc(
         index, shape.data(), strides_in.data(), strides_out.data(), ndim);
     out[idx_out] = CastOp<In, Out>{}(in[idx_in]);
   }

mlx/backend/cuda/copy/copy_general_dynamic.cu

@@ -41,7 +41,7 @@ __global__ void copy_gg_dynamic(
     const int64_t* offset_out) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto [idx_in, idx_out] = elem_to_loc_4d(
+    auto [idx_in, idx_out] = elem_to_loc(
         index, shape.data(), strides_in.data(), strides_out.data(), ndim);
     out[idx_out + *offset_out] = CastOp<In, Out>{}(in[idx_in + *offset_in]);
   }

mlx/backend/cuda/copy/copy_general_input.cu

@@ -34,7 +34,7 @@ __global__ void copy_g(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    IdxT idx_in = elem_to_loc_4d(index, shape.data(), strides_in.data(), ndim);
+    IdxT idx_in = elem_to_loc(index, shape.data(), strides_in.data(), ndim);
     out[index] = CastOp<In, Out>{}(in[idx_in]);
   }
 }

mlx/backend/cuda/device.cpp

@@ -9,12 +9,23 @@
 #include <future>
 #include <unordered_set>
 
-namespace mlx::core {
+namespace mlx::core::cu {
+
+namespace {
 
 // Can be tuned with MLX_MAX_OPS_PER_BUFFER
 // This should be less than 255
 constexpr int default_max_nodes_per_graph = 20;
 
+#define CHECK_CUDNN_ERROR(cmd) check_cudnn_error(#cmd, (cmd))
+
+void check_cudnn_error(const char* name, cudnnStatus_t err) {
+  if (err != CUDNN_STATUS_SUCCESS) {
+    throw std::runtime_error(
+        fmt::format("{} failed: {}.", name, cudnnGetErrorString(err)));
+  }
+}
+
 int cuda_graph_cache_size() {
   static int cache_size = []() {
     return env::get_var("MLX_CUDA_GRAPH_CACHE_SIZE", 100);
@@ -22,7 +33,7 @@ int cuda_graph_cache_size() {
   return cache_size;
 }
 
-namespace cu {
+} // namespace
 
 Device::Device(int device) : device_(device) {
   CHECK_CUDA_ERROR(cudaDeviceGetAttribute(
@@ -40,11 +51,14 @@ Device::Device(int device) : device_(device) {
   }
   // The cublasLt handle is used by matmul.
   make_current();
-  cublasLtCreate(&lt_);
+  CHECK_CUBLAS_ERROR(cublasLtCreate(&lt_));
+  // The cudnn handle is used by Convolution.
+  CHECK_CUDNN_ERROR(cudnnCreate(&cudnn_));
 }
 
 Device::~Device() {
-  cublasLtDestroy(lt_);
+  CHECK_CUDNN_ERROR(cudnnDestroy(cudnn_));
+  CHECK_CUBLAS_ERROR(cublasLtDestroy(lt_));
 }
 
 void Device::make_current() {
@@ -66,29 +80,36 @@ CommandEncoder& Device::get_command_encoder(Stream s) {
 }
 
 CommandEncoder::CaptureContext::CaptureContext(CommandEncoder& enc) : enc(enc) {
+  enc.device().make_current();
   CHECK_CUDA_ERROR(
       cudaStreamBeginCapture(enc.stream(), cudaStreamCaptureModeGlobal));
 }
 
 CommandEncoder::CaptureContext::~CaptureContext() {
   CHECK_CUDA_ERROR(cudaStreamEndCapture(enc.stream(), &graph));
+  std::unique_ptr<cudaGraph_t, void (*)(cudaGraph_t*)> graph_freer(
+      &graph, [](cudaGraph_t* p) { CHECK_CUDA_ERROR(cudaGraphDestroy(*p)); });
+  if (discard) {
+    return;
+  }
+
+  // Extract and add as single kernel node when possible.
   size_t num_nodes;
   CHECK_CUDA_ERROR(cudaGraphGetNodes(graph, NULL, &num_nodes));
   if (num_nodes == 1) {
     cudaGraphNode_t captured_node;
     CHECK_CUDA_ERROR(cudaGraphGetNodes(graph, &captured_node, &num_nodes));
-    CUDA_KERNEL_NODE_PARAMS params;
+    cudaGraphNodeType type;
-    CHECK_CUDA_ERROR(cuGraphKernelNodeGetParams(captured_node, &params));
+    CHECK_CUDA_ERROR(cudaGraphNodeGetType(captured_node, &type));
-    cudaGraphNode_t node;
+    if (type == cudaGraphNodeTypeKernel) {
-    CHECK_CUDA_ERROR(cuGraphAddKernelNode(&node, enc.graph_, NULL, 0, &params));
+      CUDA_KERNEL_NODE_PARAMS params;
-    enc.insert_graph_dependencies(GraphNode{node, 'K'});
+      CHECK_CUDA_ERROR(cuGraphKernelNodeGetParams(captured_node, &params));
-  } else {
+      enc.add_kernel_node(params);
-    cudaGraphNode_t node;
+      return;
-    CHECK_CUDA_ERROR(
+    }
-        cudaGraphAddChildGraphNode(&node, enc.graph_, NULL, 0, graph));
-    enc.insert_graph_dependencies(GraphNode{node, 'G'});
   }
-  CHECK_CUDA_ERROR(cudaGraphDestroy(graph));
+  // Otherwise add the captured graph as subgraph.
+  enc.add_graph_node(graph);
 }
 
 CommandEncoder::ConcurrentContext::ConcurrentContext(CommandEncoder& enc)
@@ -221,10 +242,7 @@ void CommandEncoder::add_kernel_node(
   kernel_params.gridDim = grid_dim;
   kernel_params.blockDim = block_dim;
   kernel_params.kernelParams = params;
-  cudaGraphNode_t node;
+  add_kernel_node(kernel_params);
-  CHECK_CUDA_ERROR(
-      cudaGraphAddKernelNode(&node, graph_, NULL, 0, &kernel_params));
-  insert_graph_dependencies(GraphNode{node, 'K'});
 }
 
 void CommandEncoder::add_kernel_node(
@@ -241,12 +259,27 @@ void CommandEncoder::add_kernel_node(
   kernel_params.blockDimY = block_dim.y;
   kernel_params.blockDimZ = block_dim.z;
   kernel_params.kernelParams = params;
-  CUgraphNode node;
+  add_kernel_node(kernel_params);
-  CHECK_CUDA_ERROR(
+}
-      cuGraphAddKernelNode(&node, graph_, NULL, 0, &kernel_params));
+
+void CommandEncoder::add_kernel_node(const cudaKernelNodeParams& params) {
+  cudaGraphNode_t node;
+  CHECK_CUDA_ERROR(cudaGraphAddKernelNode(&node, graph_, NULL, 0, &params));
   insert_graph_dependencies(GraphNode{node, 'K'});
 }
 
+void CommandEncoder::add_kernel_node(const CUDA_KERNEL_NODE_PARAMS& params) {
+  CUgraphNode node;
+  CHECK_CUDA_ERROR(cuGraphAddKernelNode(&node, graph_, NULL, 0, &params));
+  insert_graph_dependencies(GraphNode{node, 'K'});
+}
+
+void CommandEncoder::add_graph_node(cudaGraph_t child) {
+  cudaGraphNode_t node;
+  CHECK_CUDA_ERROR(cudaGraphAddChildGraphNode(&node, graph_, NULL, 0, child));
+  insert_graph_dependencies(GraphNode{node, 'G'});
+}
+
 void CommandEncoder::commit() {
   if (!temporaries_.empty()) {
     add_completed_handler([temporaries = std::move(temporaries_)]() {});
@@ -306,7 +339,6 @@ void CommandEncoder::commit() {
   }
 
   // Put completion handlers in a batch.
-  worker_.end_batch();
   worker_.commit(stream_);
 }
 
@@ -315,7 +347,6 @@ void CommandEncoder::synchronize() {
   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(); });
-  worker_.end_batch();
   commit();
   f.wait();
 }
@@ -333,6 +364,4 @@ CommandEncoder& get_command_encoder(Stream s) {
   return device(s.device).get_command_encoder(s);
 }
 
-} // namespace cu
+} // namespace mlx::core::cu
-
-} // namespace mlx::core

mlx/backend/cuda/device.h

@@ -8,6 +8,7 @@
 
 #include <cublasLt.h>
 #include <cuda.h>
+#include <cudnn.h>
 #include <thrust/execution_policy.h>
 
 #include <unordered_map>
@@ -21,6 +22,7 @@ class CommandEncoder {
     ~CaptureContext();
     cudaGraph_t graph;
     CommandEncoder& enc;
+    bool discard{false};
   };
   struct ConcurrentContext {
     ConcurrentContext(CommandEncoder& enc);
@@ -65,6 +67,11 @@ class CommandEncoder {
   void
   add_kernel_node(void* func, dim3 grid_dim, dim3 block_dim, void** params);
 
+  // Low-level graph helpers.
+  void add_kernel_node(const cudaKernelNodeParams& params);
+  void add_kernel_node(const CUDA_KERNEL_NODE_PARAMS& params);
+  void add_graph_node(cudaGraph_t child);
+
   void add_temporary(const array& arr) {
     temporaries_.push_back(arr.data_shared_ptr());
   }
@@ -73,6 +80,10 @@ class CommandEncoder {
   void maybe_commit();
   void commit();
 
+  Device& device() {
+    return device_;
+  }
+
   CudaStream& stream() {
     return stream_;
   }
@@ -137,12 +148,16 @@ class Device {
   cublasLtHandle_t lt_handle() const {
     return lt_;
   }
+  cudnnHandle_t cudnn_handle() const {
+    return cudnn_;
+  }
 
  private:
   int device_;
   int compute_capability_major_;
   int compute_capability_minor_;
   cublasLtHandle_t lt_;
+  cudnnHandle_t cudnn_;
   std::unordered_map<int, CommandEncoder> encoders_;
 };
 

mlx/backend/cuda/device/utils.cuh

@@ -49,6 +49,20 @@ store_vector(T* ptr, uint32_t offset, const AlignedVector<T, N>& vec) {
   to[offset] = vec;
 }
 
+// Helper for accessing strided data.
+template <typename T>
+struct StridedIterator {
+  T it;
+  int64_t stride;
+
+  __host__ __device__ StridedIterator(T it, int64_t stride)
+      : it(it), stride(stride) {}
+
+  __host__ __device__ auto operator[](int i) const {
+    return it[i * stride];
+  }
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 // Type limits utils
 ///////////////////////////////////////////////////////////////////////////////
@@ -204,20 +218,8 @@ inline __host__ __device__ cuda::std::tuple<IdxT, IdxT, IdxT> elem_to_loc_nd(
   return cuda::std::make_tuple(a_loc, b_loc, c_loc);
 }
 
-// Optimized version when ndim is larger than 4.
 template <typename IdxT = int64_t>
-inline __host__ __device__ IdxT
+inline __host__ __device__ cuda::std::tuple<IdxT, IdxT> elem_to_loc(
-elem_to_loc_4d(IdxT elem, const int* shape, const int64_t* strides, int ndim) {
-  IdxT loc = 0;
-  for (int i = ndim - 1; i >= 0; --i) {
-    loc += (elem % shape[i]) * IdxT(strides[i]);
-    elem /= shape[i];
-  }
-  return loc;
-}
-
-template <typename IdxT = int64_t>
-inline __host__ __device__ cuda::std::tuple<IdxT, IdxT> elem_to_loc_4d(
     IdxT elem,
     const int* shape,
     const int64_t* a_strides,
@@ -235,7 +237,7 @@ inline __host__ __device__ cuda::std::tuple<IdxT, IdxT> elem_to_loc_4d(
 }
 
 template <typename IdxT = int64_t>
-inline __host__ __device__ cuda::std::tuple<IdxT, IdxT, IdxT> elem_to_loc_4d(
+inline __host__ __device__ cuda::std::tuple<IdxT, IdxT, IdxT> elem_to_loc(
     IdxT elem,
     const int* shape,
     const int64_t* a_strides,

mlx/backend/cuda/eval.cpp

@@ -19,8 +19,6 @@ void new_stream(Stream s) {
   cudaFree(nullptr);
   // Ensure the static stream objects get created.
   cu::get_command_encoder(s);
-  // The main thread is safe to free buffers.
-  cu::allocator().register_this_thread();
 }
 
 void eval(array& arr) {

mlx/backend/cuda/event.cu

@@ -110,24 +110,26 @@ __global__ void event_signal_kernel(SharedEvent::Atomic* ac, uint64_t value) {
   event_signal(ac, value);
 }
 
+SharedEvent::Atomic* to_atomic(std::shared_ptr<Buffer> buf) {
+  return static_cast<SharedEvent::Atomic*>(buf->raw_ptr());
+}
+
 SharedEvent::SharedEvent() {
-  // Allocate cuda::atomic on managed memory.
+  buf_ = std::shared_ptr<Buffer>(
-  Atomic* ac;
+      new Buffer{allocator().malloc(sizeof(Atomic))}, [](Buffer* ptr) {
-  CHECK_CUDA_ERROR(cudaMallocManaged(&ac, sizeof(Atomic)));
+        allocator().free(*ptr);
-  new (ac) Atomic(0);
+        delete ptr;
-  ac_ = std::shared_ptr<Atomic>(ac, [](Atomic* ptr) {
+      });
-    ptr->~Atomic();
+  *static_cast<uint64_t*>(buf_->raw_ptr()) = 0;
-    allocator().cuda_free(ptr);
-  });
 }
 
 void SharedEvent::wait(uint64_t value) {
   nvtx3::scoped_range r("cu::SharedEvent::wait");
-  event_wait(ac_.get(), value);
+  event_wait(to_atomic(buf_), value);
 }
 
 void SharedEvent::wait(cudaStream_t stream, uint64_t value) {
-  event_wait_kernel<<<1, 1, 0, stream>>>(ac_.get(), value);
+  event_wait_kernel<<<1, 1, 0, stream>>>(to_atomic(buf_), value);
 }
 
 void SharedEvent::wait(Stream s, uint64_t value) {
@@ -138,17 +140,17 @@ void SharedEvent::wait(Stream s, uint64_t value) {
     auto& encoder = get_command_encoder(s);
     encoder.commit();
     wait(encoder.stream(), value);
-    encoder.add_completed_handler([ac = ac_]() {});
+    encoder.add_completed_handler([buf = buf_]() {});
   }
 }
 
 void SharedEvent::signal(uint64_t value) {
   nvtx3::scoped_range r("cu::SharedEvent::signal");
-  event_signal(ac_.get(), value);
+  event_signal(to_atomic(buf_), value);
 }
 
 void SharedEvent::signal(cudaStream_t stream, uint64_t value) {
-  event_signal_kernel<<<1, 1, 0, stream>>>(ac_.get(), value);
+  event_signal_kernel<<<1, 1, 0, stream>>>(to_atomic(buf_), value);
 }
 
 void SharedEvent::signal(Stream s, uint64_t value) {
@@ -162,18 +164,18 @@ void SharedEvent::signal(Stream s, uint64_t value) {
     auto& encoder = get_command_encoder(s);
     encoder.commit();
     signal(encoder.stream(), value);
-    encoder.add_completed_handler([ac = ac_]() {});
+    encoder.add_completed_handler([buf = buf_]() {});
   }
 }
 
 bool SharedEvent::is_signaled(uint64_t value) const {
   nvtx3::scoped_range r("cu::SharedEvent::is_signaled");
-  return ac_->load() >= value;
+  return to_atomic(buf_)->load() >= value;
 }
 
 uint64_t SharedEvent::value() const {
   nvtx3::scoped_range r("cu::SharedEvent::value");
-  return ac_->load();
+  return to_atomic(buf_)->load();
 }
 
 } // namespace cu

mlx/backend/cuda/event.h

@@ -2,6 +2,7 @@
 
 #pragma once
 
+#include "mlx/allocator.h"
 #include "mlx/stream.h"
 
 #include <cuda_runtime.h>
@@ -55,12 +56,8 @@ class SharedEvent {
   bool is_signaled(uint64_t value) const;
   uint64_t value() const;
 
-  const std::shared_ptr<Atomic>& atomic() const {
-    return ac_;
-  }
-
  private:
-  std::shared_ptr<Atomic> ac_;
+  std::shared_ptr<mlx::core::allocator::Buffer> buf_;
 };
 
 } // namespace mlx::core::cu

mlx/backend/cuda/gemms/cublas_batched_gemm_12_0.cpp

@@ -0,0 +1,73 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/common/utils.h"
+#include "mlx/backend/cuda/device.h"
+#include "mlx/backend/cuda/gemms/cublas_gemm.h"
+
+namespace mlx::core::cu {
+
+void Matmul::run_batched(
+    cu::CommandEncoder& encoder,
+    array& out,
+    const array& a,
+    const array& b,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides) {
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  encoder.set_output_array(out);
+  auto nbatch = out.size() / (M_ * N_ * batch_shape.back());
+  ContiguousIterator a_it(batch_shape, a_batch_strides, batch_shape.size() - 1);
+  ContiguousIterator b_it(batch_shape, b_batch_strides, batch_shape.size() - 1);
+  auto concurrent = encoder.concurrent_context();
+  for (size_t i = 0; i < nbatch; ++i) {
+    run_impl(
+        encoder,
+        out.data<int8_t>() + out.itemsize() * i * batch_shape.back() * M_ * N_,
+        a.data<int8_t>() + a.itemsize() * a_it.loc,
+        b.data<int8_t>() + b.itemsize() * b_it.loc,
+        nullptr);
+    a_it.step();
+    b_it.step();
+  }
+}
+
+void Matmul::run_batched(
+    cu::CommandEncoder& encoder,
+    array& out,
+    const array& a,
+    const array& b,
+    const array& c,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides,
+    const mlx::core::Strides& c_batch_strides,
+    float alpha,
+    float beta) {
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  encoder.set_input_array(c);
+  encoder.set_output_array(out);
+
+  auto nbatch = out.size() / (M_ * N_ * batch_shape.back());
+  ContiguousIterator a_it(batch_shape, a_batch_strides, batch_shape.size() - 1);
+  ContiguousIterator b_it(batch_shape, b_batch_strides, batch_shape.size() - 1);
+  ContiguousIterator c_it(batch_shape, c_batch_strides, batch_shape.size() - 1);
+  auto concurrent = encoder.concurrent_context();
+  for (size_t i = 0; i < nbatch; ++i) {
+    run_impl(
+        encoder,
+        out.data<int8_t>() + out.itemsize() * i * batch_shape.back() * M_ * N_,
+        a.data<int8_t>() + a.itemsize() * a_it.loc,
+        b.data<int8_t>() + b.itemsize() * b_it.loc,
+        c.data<int8_t>() + c.itemsize() * c_it.loc,
+        alpha,
+        beta);
+    a_it.step();
+    b_it.step();
+    c_it.step();
+  }
+}
+
+} // namespace mlx::core::cu

mlx/backend/cuda/gemms/cublas_batched_gemm_12_9.cu

@@ -0,0 +1,206 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/device.h"
+#include "mlx/backend/cuda/gemms/cublas_gemm.h"
+#include "mlx/backend/cuda/kernel_utils.cuh"
+
+#include <cooperative_groups.h>
+
+namespace mlx::core::cu {
+
+namespace cg = cooperative_groups;
+
+__global__ void set_mm_device_pointers(
+    int8_t** pointers,
+    int8_t* a_start,
+    int8_t* b_start,
+    int8_t* out_start,
+    int item_size,
+    const __grid_constant__ Shape batch_shape,
+    const __grid_constant__ Strides a_batch_strides,
+    const __grid_constant__ Strides b_batch_strides,
+    int64_t batch_stride,
+    int batch_ndim,
+    int batch_count) {
+  auto index = cg::this_grid().thread_rank();
+  if (index >= batch_count) {
+    return;
+  }
+  auto [a_offset, b_offset] = elem_to_loc(
+      index,
+      batch_shape.data(),
+      a_batch_strides.data(),
+      b_batch_strides.data(),
+      batch_ndim);
+  pointers[index] = a_start + item_size * a_offset;
+  pointers[index + batch_count] = b_start + item_size * b_offset;
+  pointers[index + 2 * batch_count] =
+      out_start + item_size * index * batch_stride;
+}
+
+__global__ void set_addmm_device_pointers(
+    int8_t** pointers,
+    int8_t* a_start,
+    int8_t* b_start,
+    int8_t* c_start,
+    int8_t* out_start,
+    int item_size,
+    const __grid_constant__ Shape batch_shape,
+    const __grid_constant__ Strides a_batch_strides,
+    const __grid_constant__ Strides b_batch_strides,
+    const __grid_constant__ Strides c_batch_strides,
+    int64_t batch_stride,
+    int batch_ndim,
+    int batch_count) {
+  auto index = cg::this_grid().thread_rank();
+  if (index >= batch_count) {
+    return;
+  }
+  auto [a_offset, b_offset, c_offset] = elem_to_loc(
+      index,
+      batch_shape.data(),
+      a_batch_strides.data(),
+      b_batch_strides.data(),
+      c_batch_strides.data(),
+      batch_ndim);
+  pointers[index] = a_start + item_size * a_offset;
+  pointers[index + batch_count] = b_start + item_size * b_offset;
+  pointers[index + 2 * batch_count] = c_start + item_size * c_offset;
+  pointers[index + 3 * batch_count] =
+      out_start + item_size * index * batch_stride;
+}
+
+void set_pointer_mode(cublasLtMatrixLayout_t desc, int batch_count) {
+  auto batch_mode = CUBLASLT_BATCH_MODE_POINTER_ARRAY;
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
+      desc,
+      CUBLASLT_MATRIX_LAYOUT_BATCH_MODE,
+      &batch_mode,
+      sizeof(batch_mode)));
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
+      desc, CUBLASLT_MATRIX_LAYOUT_BATCH_COUNT, &batch_count, sizeof(int32_t)));
+}
+
+void Matmul::run_batched(
+    cu::CommandEncoder& encoder,
+    array& out,
+    const array& a,
+    const array& b,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides) {
+  auto batch_count = out.size() / (M_ * N_);
+  set_pointer_mode(a_desc_, batch_count);
+  set_pointer_mode(b_desc_, batch_count);
+  set_pointer_mode(out_desc_, batch_count);
+
+  // Launch kernel to set device offsets
+  auto pointers = array(
+      allocator::malloc(batch_count * sizeof(uint64_t) * 3),
+      {static_cast<int>(batch_count * 3)},
+      uint64);
+
+  encoder.add_temporary(pointers);
+  int block_size = 512;
+  encoder.set_output_array(pointers);
+
+  encoder.add_kernel_node(
+      cu::set_mm_device_pointers,
+      cuda::ceil_div(pointers.size(), block_size),
+      block_size,
+      pointers.data<int8_t*>(),
+      a.data<int8_t>(),
+      b.data<int8_t>(),
+      out.data<int8_t>(),
+      static_cast<int>(out.dtype().size()),
+      const_param(batch_shape),
+      const_param(a_batch_strides),
+      const_param(b_batch_strides),
+      static_cast<int64_t>(M_) * N_,
+      static_cast<int>(batch_shape.size()),
+      batch_count);
+
+  // Run matmul
+  encoder.set_input_array(pointers);
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  encoder.set_output_array(out);
+
+  auto a_pointers = pointers.data<int8_t*>();
+  auto b_pointers = a_pointers + batch_count;
+  auto out_pointers = b_pointers + batch_count;
+  run_impl(
+      encoder,
+      reinterpret_cast<void*>(out_pointers),
+      reinterpret_cast<void*>(a_pointers),
+      reinterpret_cast<void*>(b_pointers),
+      nullptr);
+}
+
+void Matmul::run_batched(
+    cu::CommandEncoder& encoder,
+    array& out,
+    const array& a,
+    const array& b,
+    const array& c,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides,
+    const mlx::core::Strides& c_batch_strides,
+    float alpha,
+    float beta) {
+  auto batch_count = out.size() / (M_ * N_);
+  set_pointer_mode(a_desc_, batch_count);
+  set_pointer_mode(b_desc_, batch_count);
+  set_pointer_mode(c_desc_, batch_count);
+  set_pointer_mode(out_desc_, batch_count);
+
+  // Launch kernel to set device offsets
+  auto pointers = array(
+      allocator::malloc(batch_count * sizeof(uint64_t) * 4),
+      {static_cast<int>(batch_count * 4)},
+      uint64);
+
+  encoder.add_temporary(pointers);
+  int block_size = 512;
+  encoder.set_output_array(pointers);
+  encoder.add_kernel_node(
+      cu::set_addmm_device_pointers,
+      cuda::ceil_div(pointers.size(), block_size),
+      block_size,
+      pointers.data<int8_t*>(),
+      a.data<int8_t>(),
+      b.data<int8_t>(),
+      c.data<int8_t>(),
+      out.data<int8_t>(),
+      static_cast<int>(out.dtype().size()),
+      const_param(batch_shape),
+      const_param(a_batch_strides),
+      const_param(b_batch_strides),
+      const_param(c_batch_strides),
+      static_cast<int64_t>(M_) * N_,
+      static_cast<int>(batch_shape.size()),
+      batch_count);
+
+  // Run matmul
+  encoder.set_input_array(pointers);
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  encoder.set_input_array(c);
+  encoder.set_output_array(out);
+
+  auto a_pointers = pointers.data<int8_t*>();
+  auto b_pointers = a_pointers + batch_count;
+  auto c_pointers = b_pointers + batch_count;
+  auto out_pointers = c_pointers + batch_count;
+  run_impl(
+      encoder,
+      reinterpret_cast<void*>(out_pointers),
+      reinterpret_cast<void*>(a_pointers),
+      reinterpret_cast<void*>(b_pointers),
+      reinterpret_cast<void*>(c_pointers),
+      alpha,
+      beta);
+}
+
+} // namespace mlx::core::cu

mlx/backend/cuda/gemms/cublas_gemm.cpp

@@ -0,0 +1,282 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/gemms/cublas_gemm.h"
+#include "mlx/backend/cuda/device.h"
+#include "mlx/dtype_utils.h"
+#include "mlx/utils.h"
+
+#include <fmt/format.h>
+
+namespace mlx::core::cu {
+
+struct CublasPreference {
+  CublasPreference(Device& device) {
+    // The recommended cublas workspace size is 4 MiB for pre-Hopper and 32 MiB
+    // for Hopper+:
+    // https://docs.nvidia.com/cuda/cublas/#cublassetworkspace
+    uint64_t MiB = 1024 * 1024;
+    uint64_t workspace_size =
+        device.compute_capability_major() >= 9 ? 32 * MiB : 4 * MiB;
+
+    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceCreate(&pref_));
+    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceSetAttribute(
+        pref_,
+        CUBLASLT_MATMUL_PREF_MAX_WORKSPACE_BYTES,
+        &workspace_size,
+        sizeof(uint64_t)));
+  }
+
+  ~CublasPreference() {
+    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceDestroy(pref_));
+  }
+
+  cublasLtMatmulPreference_t pref_{nullptr};
+};
+
+cublasLtMatmulPreference_t cublas_preference(Device& device) {
+  static CublasPreference pref(device);
+  return pref.pref_;
+}
+
+cublasComputeType_t dtype_to_compute_type(Dtype dtype) {
+  switch (dtype) {
+    case float16:
+      return CUBLAS_COMPUTE_32F;
+    case bfloat16:
+      return CUBLAS_COMPUTE_32F;
+    case float32:
+      return mlx::core::env::enable_tf32() ? CUBLAS_COMPUTE_32F_FAST_TF32
+                                           : CUBLAS_COMPUTE_32F;
+    case float64:
+    case complex64:
+      return CUBLAS_COMPUTE_64F;
+    default:
+      throw std::runtime_error(fmt::format(
+          "Unsupported dtype in Matmul: {}.", dtype_to_string(dtype)));
+  }
+}
+
+cudaDataType_t dtype_to_cublas_type(Dtype dtype) {
+  switch (dtype) {
+    case float16:
+      return CUDA_R_16F;
+    case bfloat16:
+      return CUDA_R_16BF;
+    case float32:
+      return CUDA_R_32F;
+    case float64:
+      return CUDA_R_64F;
+    case complex64:
+      return CUDA_C_32F;
+    default:
+      throw std::runtime_error(fmt::format(
+          "Unsupported dtype in Matmul: {}.", dtype_to_string(dtype)));
+  }
+}
+
+cublasLtMatrixLayout_t create_matrix_layout(
+    cudaDataType_t type,
+    uint64_t rows,
+    uint64_t cols,
+    bool transposed,
+    int64_t ld,
+    int32_t batch_count,
+    int64_t batch_stride) {
+  cublasLtMatrixLayout_t desc;
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutCreate(&desc, type, rows, cols, ld));
+  cublasLtOrder_t order = transposed ? CUBLASLT_ORDER_COL : CUBLASLT_ORDER_ROW;
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
+      desc, CUBLASLT_MATRIX_LAYOUT_ORDER, &order, sizeof(cublasLtOrder_t)));
+  if (batch_count > 1) {
+    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
+        desc,
+        CUBLASLT_MATRIX_LAYOUT_BATCH_COUNT,
+        &batch_count,
+        sizeof(int32_t)));
+    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
+        desc,
+        CUBLASLT_MATRIX_LAYOUT_STRIDED_BATCH_OFFSET,
+        &batch_stride,
+        sizeof(int64_t)));
+  }
+  return desc;
+}
+
+Matmul::Matmul(
+    Device& device,
+    Dtype dtype,
+    bool a_transposed,
+    uint64_t a_rows,
+    uint64_t a_cols,
+    int64_t lda,
+    bool b_transposed,
+    uint64_t b_rows,
+    uint64_t b_cols,
+    int64_t ldb,
+    int32_t batch_count,
+    int64_t a_batch_stride,
+    int64_t b_batch_stride)
+    : handle_(device.lt_handle()),
+      pref_(cublas_preference(device)),
+      M_(a_rows),
+      N_(b_cols) {
+  heuristic_.state = CUBLAS_STATUS_NOT_INITIALIZED;
+
+  auto scale_type = dtype_to_cublas_type(dtype);
+  if (dtype == bfloat16 || dtype == float16) {
+    scale_type = CUDA_R_32F;
+  }
+  CHECK_CUBLAS_ERROR(cublasLtMatmulDescCreate(
+      &matmul_desc_, dtype_to_compute_type(dtype), scale_type));
+  int32_t pointer_mode = CUBLASLT_POINTER_MODE_HOST;
+  CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
+      matmul_desc_,
+      CUBLASLT_MATMUL_DESC_POINTER_MODE,
+      &pointer_mode,
+      sizeof(int32_t)));
+  cublasOperation_t op = CUBLAS_OP_N;
+  CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
+      matmul_desc_,
+      CUBLASLT_MATMUL_DESC_TRANSA,
+      &op,
+      sizeof(cublasOperation_t)));
+  CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
+      matmul_desc_,
+      CUBLASLT_MATMUL_DESC_TRANSB,
+      &op,
+      sizeof(cublasOperation_t)));
+
+  auto type = dtype_to_cublas_type(dtype);
+  a_desc_ = create_matrix_layout(
+      type, a_rows, a_cols, a_transposed, lda, batch_count, a_batch_stride);
+  b_desc_ = create_matrix_layout(
+      type, b_rows, b_cols, b_transposed, ldb, batch_count, b_batch_stride);
+  out_desc_ = create_matrix_layout(
+      type, a_rows, b_cols, false, b_cols, batch_count, a_rows * b_cols);
+}
+
+Matmul::Matmul(
+    Device& device,
+    Dtype dtype,
+    bool a_transposed,
+    uint64_t a_rows,
+    uint64_t a_cols,
+    int64_t lda,
+    bool b_transposed,
+    uint64_t b_rows,
+    uint64_t b_cols,
+    int64_t ldb,
+    int64_t ldc,
+    int32_t batch_count,
+    int64_t a_batch_stride,
+    int64_t b_batch_stride,
+    int64_t c_batch_stride)
+    : Matmul(
+          device,
+          dtype,
+          a_transposed,
+          a_rows,
+          a_cols,
+          lda,
+          b_transposed,
+          b_rows,
+          b_cols,
+          ldb,
+          batch_count,
+          a_batch_stride,
+          b_batch_stride) {
+  auto type = dtype_to_cublas_type(dtype);
+  c_desc_ = create_matrix_layout(
+      type, a_rows, b_cols, false, ldc, batch_count, c_batch_stride);
+}
+
+Matmul::~Matmul() {
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(a_desc_));
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(b_desc_));
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(c_desc_));
+  CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(out_desc_));
+  CHECK_CUBLAS_ERROR(cublasLtMatmulDescDestroy(matmul_desc_));
+}
+
+void Matmul::run_impl(
+    cu::CommandEncoder& encoder,
+    void* out,
+    const void* a,
+    const void* b,
+    const void* c,
+    float alpha /* = 1 */,
+    float beta /* = 0 */) {
+  if (heuristic_.state != CUBLAS_STATUS_SUCCESS) {
+    int ret = 0;
+    CHECK_CUBLAS_ERROR(cublasLtMatmulAlgoGetHeuristic(
+        handle_,
+        matmul_desc_,
+        a_desc_,
+        b_desc_,
+        out_desc_, // TODO should that be c_desc is it's set?
+        out_desc_,
+        pref_,
+        1,
+        &heuristic_,
+        &ret));
+    if (ret == 0) {
+      throw std::runtime_error("Can not find algorithm for matmul.");
+    }
+  }
+
+  void* workspace_ptr = nullptr;
+  if (heuristic_.workspaceSize > 0) {
+    array workspace(
+        allocator::malloc(heuristic_.workspaceSize),
+        {static_cast<int>(heuristic_.workspaceSize)},
+        int8);
+    encoder.add_temporary(workspace);
+    workspace_ptr = workspace.data<void>();
+  }
+
+  auto capture = encoder.capture_context();
+  CHECK_CUBLAS_ERROR(cublasLtMatmul(
+      handle_,
+      matmul_desc_,
+      &alpha,
+      a,
+      a_desc_,
+      b,
+      b_desc_,
+      &beta,
+      c ? c : out,
+      c ? c_desc_ : out_desc_,
+      out,
+      out_desc_,
+      &heuristic_.algo,
+      workspace_ptr,
+      heuristic_.workspaceSize,
+      encoder.stream()));
+}
+
+void Matmul::run(
+    cu::CommandEncoder& encoder,
+    array& out,
+    const array& a,
+    const array& b,
+    const std::optional<array>& c /* = std::nullopt */,
+    float alpha /* = 1 */,
+    float beta /* = 0 */) {
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  if (c) {
+    encoder.set_input_array(*c);
+  }
+  encoder.set_output_array(out);
+
+  run_impl(
+      encoder,
+      out.data<void>(),
+      a.data<void>(),
+      b.data<void>(),
+      c ? c->data<void>() : nullptr,
+      alpha,
+      beta);
+}
+
+} // namespace mlx::core::cu

mlx/backend/cuda/gemms/cublas_gemm.h

@@ -0,0 +1,100 @@
+// Copyright © 2025 Apple Inc.
+#pragma once
+
+#include "mlx/array.h"
+#include "mlx/backend/cuda/device.h"
+
+#include <cublasLt.h>
+#include <optional>
+
+namespace mlx::core::cu {
+class Matmul {
+ public:
+  Matmul(
+      Device& device,
+      Dtype dtype,
+      bool a_transposed,
+      uint64_t a_rows,
+      uint64_t a_cols,
+      int64_t lda,
+      bool b_transposed,
+      uint64_t b_rows,
+      uint64_t b_cols,
+      int64_t ldb,
+      int32_t batch_count,
+      int64_t a_batch_stride,
+      int64_t b_batch_stride);
+
+  Matmul(
+      Device& device,
+      Dtype dtype,
+      bool a_transposed,
+      uint64_t a_rows,
+      uint64_t a_cols,
+      int64_t lda,
+      bool b_transposed,
+      uint64_t b_rows,
+      uint64_t b_cols,
+      int64_t ldb,
+      int64_t ldc,
+      int32_t batch_count,
+      int64_t a_batch_stride,
+      int64_t b_batch_stride,
+      int64_t c_batch_stride);
+
+  ~Matmul();
+
+  void run(
+      cu::CommandEncoder& encoder,
+      array& out,
+      const array& a,
+      const array& b,
+      const std::optional<array>& c = std::nullopt,
+      float alpha = 1,
+      float beta = 0);
+
+  void run_batched(
+      cu::CommandEncoder& encoder,
+      array& out,
+      const array& a,
+      const array& b,
+      const mlx::core::Shape& batch_shape,
+      const mlx::core::Strides& a_batch_strides,
+      const mlx::core::Strides& b_batch_strides);
+
+  void run_batched(
+      cu::CommandEncoder& encoder,
+      array& out,
+      const array& a,
+      const array& b,
+      const array& c,
+      const mlx::core::Shape& batch_shape,
+      const mlx::core::Strides& a_batch_strides,
+      const mlx::core::Strides& b_batch_strides,
+      const mlx::core::Strides& c_batch_strides,
+      float alpha,
+      float beta);
+
+ private:
+  void run_impl(
+      cu::CommandEncoder& encoder,
+      void* out,
+      const void* a,
+      const void* b,
+      const void* c,
+      float alpha = 1,
+      float beta = 0);
+
+  uint64_t M_;
+  uint64_t N_;
+  cublasLtMatmulPreference_t pref_{nullptr};
+  cublasLtHandle_t handle_{nullptr};
+  cublasLtMatmulDesc_t matmul_desc_{nullptr};
+  cublasLtMatrixLayout_t a_desc_{nullptr};
+  cublasLtMatrixLayout_t b_desc_{nullptr};
+  cublasLtMatrixLayout_t c_desc_{nullptr};
+  cublasLtMatrixLayout_t out_desc_{nullptr};
+  cublasLtMatmulHeuristicResult_t heuristic_;
+};
+
+} // namespace mlx::core::cu

mlx/backend/cuda/gemms/gemv.cu

@@ -0,0 +1,147 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/gemms/gemv.h"
+#include "mlx/backend/cuda/kernel_utils.cuh"
+#include "mlx/dtype_utils.h"
+
+#include <cooperative_groups.h>
+#include <cooperative_groups/reduce.h>
+
+namespace mlx::core::cu {
+
+namespace cg = cooperative_groups;
+
+static constexpr int n_per_thread = 4;
+static constexpr int rows_per_block = 8;
+
+template <typename T, int rows_per_block, int n_per_thread>
+__device__ void
+gemv_impl(const T* mat, const T* vec, T* out, int rows, int cols) {
+  auto block = cg::this_thread_block();
+  auto warp = cg::tiled_partition<WARP_SIZE>(block);
+
+  auto g_idx = block.group_index();
+  auto t_idx = block.thread_index();
+  int row = g_idx.x * rows_per_block + t_idx.y;
+
+  if (row < rows) {
+    float sum = 0.0f;
+    for (int col = n_per_thread * warp.thread_rank(); col < cols;
+         col += (WARP_SIZE * n_per_thread)) {
+      auto local_mat = load_vector<n_per_thread>(mat + row * cols + col, 0);
+      auto local_vec = load_vector<n_per_thread>(vec + col, 0);
+#pragma unroll
+      for (int j = 0; j < n_per_thread; ++j) {
+        sum += static_cast<float>(local_mat.val[j]) *
+            static_cast<float>(local_vec.val[j]);
+      }
+    }
+
+    sum = cg::reduce(warp, sum, cg::plus<float>{});
+    if (warp.thread_rank() == 0) {
+      out[row] = static_cast<T>(sum);
+    }
+  }
+}
+
+template <typename T, int rows_per_block, int n_per_thread>
+__global__ void
+gemv_single(const T* mat, const T* vec, T* out, int rows, int cols) {
+  gemv_impl<T, rows_per_block, n_per_thread>(mat, vec, out, rows, cols);
+}
+
+template <typename T, int rows_per_block, int n_per_thread>
+__global__ void gemv_batched(
+    const T* mat,
+    const T* vec,
+    T* out,
+    int rows,
+    int cols,
+    const __grid_constant__ Shape batch_shape,
+    const __grid_constant__ Strides mat_batch_strides,
+    const __grid_constant__ Strides vec_batch_strides,
+    int batch_ndim) {
+  auto block = cg::this_thread_block();
+  auto batch_idx = block.group_index().y;
+  auto [vec_offset, mat_offset] = elem_to_loc(
+      batch_idx,
+      batch_shape.data(),
+      vec_batch_strides.data(),
+      mat_batch_strides.data(),
+      batch_ndim);
+  gemv_impl<T, rows_per_block, n_per_thread>(
+      mat + mat_offset, vec + vec_offset, out + batch_idx * rows, rows, cols);
+}
+
+bool can_use_gemv(int M, int N, int K, bool a_transposed, bool b_transposed) {
+  return K % (WARP_SIZE * n_per_thread) == 0 &&
+      ((M == 1 && b_transposed) || (N == 1 && !a_transposed));
+}
+
+void gemv(
+    const array& a,
+    const array& b,
+    array& out,
+    int M,
+    int N,
+    int K,
+    uint32_t batch_count,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides,
+    CommandEncoder& encoder) {
+  encoder.set_input_array(a);
+  encoder.set_input_array(b);
+  encoder.set_output_array(out);
+  dispatch_float_types(out.dtype(), "gemv", [&](auto type_tag) {
+    using DataType = cuda_type_t<MLX_GET_TYPE(type_tag)>;
+    dim3 block_dims{WARP_SIZE, rows_per_block};
+    const DataType* mat;
+    const DataType* vec;
+    int rows;
+    int cols = K;
+    auto mat_strides = const_param(a_batch_strides);
+    auto vec_strides = const_param(b_batch_strides);
+
+    if (M == 1) {
+      mat = b.data<DataType>();
+      vec = a.data<DataType>();
+      rows = N;
+      std::swap(mat_strides, vec_strides);
+    } else {
+      mat = a.data<DataType>();
+      vec = b.data<DataType>();
+      rows = M;
+    }
+    uint32_t num_blocks_x = (rows + rows_per_block - 1) / rows_per_block;
+    if (batch_count == 1) {
+      auto kernel = gemv_single<DataType, rows_per_block, n_per_thread>;
+      encoder.add_kernel_node(
+          kernel,
+          num_blocks_x,
+          block_dims,
+          mat,
+          vec,
+          out.data<DataType>(),
+          rows,
+          cols);
+    } else {
+      auto kernel = gemv_batched<DataType, rows_per_block, n_per_thread>;
+      encoder.add_kernel_node(
+          kernel,
+          dim3{num_blocks_x, batch_count},
+          block_dims,
+          mat,
+          vec,
+          out.data<DataType>(),
+          rows,
+          cols,
+          const_param(batch_shape),
+          mat_strides,
+          vec_strides,
+          batch_shape.size());
+    }
+  });
+}
+
+} // namespace mlx::core::cu

mlx/backend/cuda/gemms/gemv.h

@@ -0,0 +1,24 @@
+// Copyright © 2025 Apple Inc.
+
+#pragma once
+
+#include "mlx/backend/cuda/device.h"
+
+namespace mlx::core::cu {
+
+bool can_use_gemv(int M, int N, int K, bool a_transposed, bool b_transposed);
+
+void gemv(
+    const array& a,
+    const array& b,
+    array& out,
+    int M,
+    int N,
+    int K,
+    uint32_t batch_count,
+    const mlx::core::Shape& batch_shape,
+    const mlx::core::Strides& a_batch_strides,
+    const mlx::core::Strides& b_batch_strides,
+    CommandEncoder& encoder);
+
+} // namespace mlx::core::cu

mlx/backend/cuda/iterators/general_iterator.cuh

@@ -1,121 +0,0 @@
-// Copyright © 2025 Apple Inc.
-
-#pragma once
-
-#include <thrust/iterator/iterator_adaptor.h>
-#include <cuda/std/utility>
-
-#include "mlx/backend/cuda/kernel_utils.cuh"
-
-namespace mlx::core::cu {
-
-// Iterating non-contiguous array.
-template <typename Iterator, typename IdxT = int64_t>
-class general_iterator
-    : public thrust::
-          iterator_adaptor<general_iterator<Iterator, IdxT>, Iterator> {
- public:
-  using super_t =
-      thrust::iterator_adaptor<general_iterator<Iterator, IdxT>, Iterator>;
-
-  using reference = typename super_t::reference;
-  using difference_type = typename super_t::difference_type;
-
-  __host__ __device__ general_iterator(
-      Iterator it,
-      IdxT index,
-      int ndim,
-      Shape shape,
-      Strides strides)
-      : super_t(it),
-        index_(index),
-        ndim_(ndim),
-        shape_(cuda::std::move(shape)),
-        strides_(cuda::std::move(strides)) {}
-
-  __host__ __device__ IdxT index() const {
-    return index_;
-  }
-
-  __host__ __device__ const Shape& shape() const {
-    return shape_;
-  }
-
-  __host__ __device__ const Strides& strides() const {
-    return strides_;
-  }
-
- private:
-  friend class thrust::iterator_core_access;
-
-  __host__ __device__ bool equal(const general_iterator& other) const {
-    return this->base() == other.base() && this->index() == other.index();
-  }
-
-  __host__ __device__ void advance(difference_type n) {
-    this->index_ += n;
-  }
-
-  __host__ __device__ void increment() {
-    this->index_ += 1;
-  }
-
-  __host__ __device__ void decrement() {
-    this->index_ -= 1;
-  }
-
-  __host__ __device__ difference_type
-  distance_to(const general_iterator& other) const {
-    _CCCL_ASSERT(
-        this->base() == other.base(),
-        "Underlying iterator must point to same base iterator");
-    return other.index() - this->index();
-  }
-
-  // The dereference is device-only to avoid accidental running in host.
-  __device__ typename super_t::reference dereference() const {
-    IdxT offset = elem_to_loc(index_, shape_.data(), strides_.data(), ndim_);
-    return *(this->base() + offset);
-  }
-
-  IdxT index_;
-  int ndim_;
-  Shape shape_;
-  Strides strides_;
-};
-
-template <typename IdxT, typename Iterator>
-__host__ __device__ auto make_general_iterator(
-    Iterator it,
-    IdxT index,
-    int ndim,
-    Shape shape,
-    Strides strides) {
-  return general_iterator<Iterator, IdxT>(
-      it, index, ndim, cuda::std::move(shape), cuda::std::move(strides));
-}
-
-template <typename IdxT, typename Iterator>
-auto make_general_iterator(
-    Iterator it,
-    const std::vector<int32_t>& shape,
-    const std::vector<int64_t>& strides) {
-  return make_general_iterator<IdxT>(
-      it, 0, shape.size(), const_param(shape), const_param(strides));
-}
-
-template <typename IdxT, typename Iterator>
-auto make_general_iterators(
-    Iterator it,
-    IdxT size,
-    const std::vector<int32_t>& shape,
-    const std::vector<int64_t>& strides) {
-  auto ndim = shape.size();
-  auto shape_arg = const_param(shape);
-  auto strides_arg = const_param(strides);
-  return std::make_pair(
-      make_general_iterator<IdxT>(it, 0, ndim, shape_arg, strides_arg),
-      make_general_iterator<IdxT>(it, size, ndim, shape_arg, strides_arg));
-}
-
-} // namespace mlx::core::cu

mlx/backend/cuda/iterators/strided_iterator.cuh

@@ -1,60 +0,0 @@
-// Copyright © 2025 Apple Inc.
-
-#pragma once
-
-#include <thrust/iterator/iterator_adaptor.h>
-#include <thrust/iterator/iterator_facade.h>
-
-namespace mlx::core::cu {
-
-// RandomAccessIterator for strided access to array entries.
-template <typename Iterator, typename Stride = int64_t>
-class strided_iterator
-    : public thrust::
-          iterator_adaptor<strided_iterator<Iterator, Stride>, Iterator> {
- public:
-  using super_t =
-      thrust::iterator_adaptor<strided_iterator<Iterator, Stride>, Iterator>;
-
-  using reference = typename super_t::reference;
-  using difference_type = typename super_t::difference_type;
-
-  __host__ __device__ strided_iterator(Iterator it, Stride stride)
-      : super_t(it), stride_(stride) {}
-
-  __host__ __device__ Stride stride() const {
-    return stride_;
-  }
-
- private:
-  friend class thrust::iterator_core_access;
-
-  __host__ __device__ bool equal(const strided_iterator& other) const {
-    return this->base() == other.base();
-  }
-
-  __host__ __device__ void advance(difference_type n) {
-    this->base_reference() += n * stride_;
-  }
-
-  __host__ __device__ void increment() {
-    this->base_reference() += stride_;
-  }
-
-  __host__ __device__ void decrement() {
-    this->base_reference() -= stride_;
-  }
-
-  __host__ __device__ difference_type
-  distance_to(const strided_iterator& other) const {
-    const difference_type dist = other.base() - this->base();
-    _CCCL_ASSERT(
-        dist % stride() == 0,
-        "Underlying iterator difference must be divisible by the stride");
-    return dist / stride();
-  }
-
-  Stride stride_;
-};
-
-} // namespace mlx::core::cu

mlx/backend/cuda/layer_norm.cu

@@ -1,7 +1,6 @@
 // Copyright © 2025 Apple Inc.
 
 #include "mlx/backend/cuda/device.h"
-#include "mlx/backend/cuda/iterators/strided_iterator.cuh"
 #include "mlx/backend/cuda/kernel_utils.cuh"
 #include "mlx/backend/cuda/reduce/reduce.cuh"
 #include "mlx/backend/gpu/copy.h"
@@ -105,8 +104,8 @@ __global__ void layer_norm(
     T wn[N_READS];
     T bn[N_READS];
     cub::LoadDirectBlocked(index, x, xn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(b, b_stride), bn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(b, b_stride), bn, axis_size);
     for (int i = 0; i < N_READS; ++i) {
       float norm = (static_cast<float>(xn[i]) - mean) * normalizer;
       xn[i] = wn[i] * static_cast<T>(norm) + bn[i];
@@ -162,7 +161,7 @@ __global__ void layer_norm_vjp(
     auto index = r * BLOCK_DIM + block.thread_rank();
     cub::LoadDirectBlocked(index, x, xn, axis_size, mean);
     cub::LoadDirectBlocked(index, g, gn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
     for (int i = 0; i < N_READS; i++) {
       float t = static_cast<float>(xn[i]) - mean;
       float wi = wn[i];
@@ -185,7 +184,7 @@ __global__ void layer_norm_vjp(
     T gn[N_READS];
     cub::LoadDirectBlocked(index, x, xn, axis_size);
     cub::LoadDirectBlocked(index, g, gn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
     for (int i = 0; i < N_READS; i++) {
       float xi = (static_cast<float>(xn[i]) - mean) * normalizer;
       float wi = wn[i];

mlx/backend/cuda/lru_cache.h

@@ -0,0 +1,146 @@
+// Copyright © 2025 Apple Inc.
+
+#pragma once
+
+#include <list>
+#include <unordered_map>
+#include <utility>
+
+namespace mlx::core {
+
+template <
+    typename K,
+    typename V,
+    template <typename...> typename M = std::unordered_map>
+class LRUCache {
+ public:
+  using value_type = std::pair<K, V>;
+  using list_type = std::list<value_type>;
+  using iterator = typename list_type::iterator;
+  using const_iterator = typename list_type::const_iterator;
+  using map_type = M<K, iterator>;
+
+  explicit LRUCache(size_t capacity) : capacity_(capacity) {}
+
+  size_t size() const {
+    return map_.size();
+  }
+  size_t capacity() const {
+    return capacity_;
+  }
+  bool empty() const {
+    return vlist_.empty();
+  }
+
+  void resize(size_t new_capacity) {
+    capacity_ = new_capacity;
+    trim();
+  }
+
+  iterator begin() {
+    return vlist_.begin();
+  }
+  const_iterator begin() const {
+    return vlist_.begin();
+  }
+  iterator end() {
+    return vlist_.end();
+  }
+  const_iterator end() const {
+    return vlist_.end();
+  }
+
+  void clear() {
+    map_.clear();
+    vlist_.clear();
+  }
+
+  iterator find(const K& key) {
+    auto it = map_.find(key);
+    if (it == map_.end())
+      return end();
+    vlist_.splice(vlist_.begin(), vlist_, it->second);
+    return it->second;
+  }
+
+  template <typename U>
+  std::pair<iterator, bool> emplace(const K& key, U&& value) {
+    auto it = map_.find(key);
+    if (it != map_.end()) {
+      vlist_.splice(vlist_.begin(), vlist_, it->second);
+      return {it->second, false};
+    }
+
+    vlist_.emplace_front(key, std::forward<U>(value));
+    map_[key] = vlist_.begin();
+
+    trim();
+
+    return {vlist_.begin(), true};
+  }
+
+  iterator erase(iterator pos) {
+    map_.erase(pos->first);
+    return vlist_.erase(pos);
+  }
+
+ private:
+  void trim() {
+    while (map_.size() > capacity_) {
+      auto last = std::prev(vlist_.end());
+      map_.erase(last->first);
+      vlist_.pop_back();
+    }
+  }
+
+  list_type vlist_;
+  map_type map_;
+  size_t capacity_;
+};
+
+// Turn a POD struct into a container key by doing bytes compare.
+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(const BytesKey& other) {
+    memcpy(&pod, &other.pod, sizeof(T));
+  }
+
+  BytesKey(BytesKey&& other) {
+    memcpy(&pod, &other.pod, sizeof(T));
+  }
+
+  bool operator==(const BytesKey& other) const {
+    auto* ptr1 = reinterpret_cast<const uint8_t*>(&pod);
+    auto* ptr2 = reinterpret_cast<const uint8_t*>(&other.pod);
+    return memcmp(ptr1, ptr2, sizeof(T)) == 0;
+  }
+};
+
+// Compute hash according to the bytes value of T.
+template <typename T>
+struct BytesHash {
+  static_assert(std::is_standard_layout_v<T>, "T is not POD");
+
+  size_t operator()(const T& pod) const {
+    auto* ptr = reinterpret_cast<const uint8_t*>(&pod);
+    uint32_t value = 0x811C9DC5;
+    for (int i = 0; i < sizeof(T); ++i) {
+      value ^= ptr[i];
+      value *= 0x01000193;
+    }
+    return value;
+  }
+};
+
+template <typename K, typename V>
+using BytesKeyHashMap = std::unordered_map<K, V, BytesHash<K>>;
+
+template <typename K, typename V>
+using LRUBytesKeyCache = LRUCache<BytesKey<K>, V, BytesKeyHashMap>;
+
+} // namespace mlx::core

mlx/backend/cuda/matmul.cpp

@@ -2,289 +2,15 @@
 
 #include "mlx/backend/common/matmul.h"
 #include "mlx/backend/cuda/device.h"
+#include "mlx/backend/cuda/gemms/cublas_gemm.h"
+#include "mlx/backend/cuda/gemms/gemv.h"
 #include "mlx/backend/gpu/copy.h"
-#include "mlx/dtype_utils.h"
 #include "mlx/primitives.h"
-#include "mlx/utils.h"
 
-#include <cublasLt.h>
-#include <fmt/format.h>
 #include <nvtx3/nvtx3.hpp>
-
 #include <numeric>
 
 namespace mlx::core {
-
-namespace cu {
-
-#define CHECK_CUBLAS_ERROR(cmd) check_cublas_error(#cmd, (cmd))
-
-void check_cublas_error(const char* name, cublasStatus_t err) {
-  if (err != CUBLAS_STATUS_SUCCESS) {
-    // TODO: Use cublasGetStatusString when it is widely available.
-    throw std::runtime_error(
-        fmt::format("{} failed with code: {}.", name, static_cast<int>(err)));
-  }
-}
-
-struct CublasPreference {
-  CublasPreference(Device& device) {
-    // The recommended cublas workspace size is 4 MiB for pre-Hopper and 32 MiB
-    // for Hopper+:
-    // https://docs.nvidia.com/cuda/cublas/#cublassetworkspace
-    uint64_t MiB = 1024 * 1024;
-    uint64_t workspace_size =
-        device.compute_capability_major() >= 9 ? 32 * MiB : 4 * MiB;
-
-    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceCreate(&pref_));
-    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceSetAttribute(
-        pref_,
-        CUBLASLT_MATMUL_PREF_MAX_WORKSPACE_BYTES,
-        &workspace_size,
-        sizeof(uint64_t)));
-  }
-
-  ~CublasPreference() {
-    CHECK_CUBLAS_ERROR(cublasLtMatmulPreferenceDestroy(pref_));
-  }
-
-  cublasLtMatmulPreference_t pref_{nullptr};
-};
-
-cublasLtMatmulPreference_t cublas_preference(Device& device) {
-  static CublasPreference pref(device);
-  return pref.pref_;
-}
-
-class MatMul {
- public:
-  MatMul(
-      Device& device,
-      Dtype dtype,
-      bool a_transposed,
-      uint64_t a_rows,
-      uint64_t a_cols,
-      int64_t lda,
-      bool b_transposed,
-      uint64_t b_rows,
-      uint64_t b_cols,
-      int64_t ldb,
-      int32_t batch_count,
-      int64_t a_batch_stride,
-      int64_t b_batch_stride)
-      : handle_(device.lt_handle()), pref_(cublas_preference(device)) {
-    heuristic_.state = CUBLAS_STATUS_NOT_INITIALIZED;
-
-    auto scale_type = dtype_to_cuda_type(dtype);
-    if (dtype == bfloat16 || dtype == float16) {
-      scale_type = CUDA_R_32F;
-    }
-    CHECK_CUBLAS_ERROR(cublasLtMatmulDescCreate(
-        &matmul_desc_, dtype_to_compute_type(dtype), scale_type));
-    int32_t pointer_mode = CUBLASLT_POINTER_MODE_HOST;
-    CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
-        matmul_desc_,
-        CUBLASLT_MATMUL_DESC_POINTER_MODE,
-        &pointer_mode,
-        sizeof(int32_t)));
-    cublasOperation_t op = CUBLAS_OP_N;
-    CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
-        matmul_desc_,
-        CUBLASLT_MATMUL_DESC_TRANSA,
-        &op,
-        sizeof(cublasOperation_t)));
-    CHECK_CUBLAS_ERROR(cublasLtMatmulDescSetAttribute(
-        matmul_desc_,
-        CUBLASLT_MATMUL_DESC_TRANSB,
-        &op,
-        sizeof(cublasOperation_t)));
-
-    auto type = dtype_to_cuda_type(dtype);
-    a_desc_ = create_matrix_layout(
-        type, a_rows, a_cols, a_transposed, lda, batch_count, a_batch_stride);
-    b_desc_ = create_matrix_layout(
-        type, b_rows, b_cols, b_transposed, ldb, batch_count, b_batch_stride);
-    out_desc_ = create_matrix_layout(
-        type, a_rows, b_cols, false, b_cols, batch_count, a_rows * b_cols);
-  }
-
-  MatMul(
-      Device& device,
-      Dtype dtype,
-      bool a_transposed,
-      uint64_t a_rows,
-      uint64_t a_cols,
-      int64_t lda,
-      bool b_transposed,
-      uint64_t b_rows,
-      uint64_t b_cols,
-      int64_t ldb,
-      int64_t ldc,
-      int32_t batch_count,
-      int64_t a_batch_stride,
-      int64_t b_batch_stride,
-      int64_t c_batch_stride)
-      : MatMul(
-            device,
-            dtype,
-            a_transposed,
-            a_rows,
-            a_cols,
-            lda,
-            b_transposed,
-            b_rows,
-            b_cols,
-            ldb,
-            batch_count,
-            a_batch_stride,
-            b_batch_stride) {
-    auto type = dtype_to_cuda_type(dtype);
-    c_desc_ = create_matrix_layout(
-        type, a_rows, b_cols, false, ldc, batch_count, c_batch_stride);
-  }
-
-  ~MatMul() {
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(a_desc_));
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(b_desc_));
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(c_desc_));
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutDestroy(out_desc_));
-    CHECK_CUBLAS_ERROR(cublasLtMatmulDescDestroy(matmul_desc_));
-  }
-
-  void run(
-      cu::CommandEncoder& encoder,
-      void* out,
-      void* a,
-      void* b,
-      void* c = nullptr,
-      float alpha = 1,
-      float beta = 0) {
-    if (heuristic_.state != CUBLAS_STATUS_SUCCESS) {
-      int ret = 0;
-      CHECK_CUBLAS_ERROR(cublasLtMatmulAlgoGetHeuristic(
-          handle_,
-          matmul_desc_,
-          a_desc_,
-          b_desc_,
-          out_desc_,
-          out_desc_,
-          pref_,
-          1,
-          &heuristic_,
-          &ret));
-      if (ret == 0) {
-        throw std::runtime_error("Can not find algorithm for matmul.");
-      }
-    }
-
-    void* workspace_ptr = nullptr;
-    if (heuristic_.workspaceSize > 0) {
-      array workspace(
-          allocator::malloc(heuristic_.workspaceSize),
-          {static_cast<int>(heuristic_.workspaceSize)},
-          int8);
-      encoder.add_temporary(workspace);
-      workspace_ptr = workspace.data<void>();
-    }
-
-    auto capture = encoder.capture_context();
-    CHECK_CUBLAS_ERROR(cublasLtMatmul(
-        handle_,
-        matmul_desc_,
-        &alpha,
-        a,
-        a_desc_,
-        b,
-        b_desc_,
-        &beta,
-        c ? c : out,
-        c ? c_desc_ : out_desc_,
-        out,
-        out_desc_,
-        &heuristic_.algo,
-        workspace_ptr,
-        heuristic_.workspaceSize,
-        encoder.stream()));
-  }
-
- private:
-  cublasComputeType_t dtype_to_compute_type(Dtype dtype) {
-    switch (dtype) {
-      case float16:
-        return CUBLAS_COMPUTE_32F;
-      case bfloat16:
-        return CUBLAS_COMPUTE_32F;
-      case float32:
-        return mlx::core::env::enable_tf32() ? CUBLAS_COMPUTE_32F_FAST_TF32
-                                             : CUBLAS_COMPUTE_32F;
-      case float64:
-      case complex64:
-        return CUBLAS_COMPUTE_64F;
-      default:
-        throw std::runtime_error(fmt::format(
-            "Unsupported dtype in MatMul: {}.", dtype_to_string(dtype)));
-    }
-  }
-
-  cudaDataType_t dtype_to_cuda_type(Dtype dtype) {
-    switch (dtype) {
-      case float16:
-        return CUDA_R_16F;
-      case bfloat16:
-        return CUDA_R_16BF;
-      case float32:
-        return CUDA_R_32F;
-      case float64:
-        return CUDA_R_64F;
-      case complex64:
-        return CUDA_C_32F;
-      default:
-        throw std::runtime_error(fmt::format(
-            "Unsupported dtype in MatMul: {}.", dtype_to_string(dtype)));
-    }
-  }
-
-  cublasLtMatrixLayout_t create_matrix_layout(
-      cudaDataType_t type,
-      uint64_t rows,
-      uint64_t cols,
-      bool transposed,
-      int64_t ld,
-      int32_t batch_count,
-      int64_t batch_stride) {
-    cublasLtMatrixLayout_t desc;
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutCreate(&desc, type, rows, cols, ld));
-    cublasLtOrder_t order =
-        transposed ? CUBLASLT_ORDER_COL : CUBLASLT_ORDER_ROW;
-    CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
-        desc, CUBLASLT_MATRIX_LAYOUT_ORDER, &order, sizeof(cublasLtOrder_t)));
-    if (batch_count > 1) {
-      CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
-          desc,
-          CUBLASLT_MATRIX_LAYOUT_BATCH_COUNT,
-          &batch_count,
-          sizeof(int32_t)));
-      CHECK_CUBLAS_ERROR(cublasLtMatrixLayoutSetAttribute(
-          desc,
-          CUBLASLT_MATRIX_LAYOUT_STRIDED_BATCH_OFFSET,
-          &batch_stride,
-          sizeof(int64_t)));
-    }
-    return desc;
-  }
-
-  cublasLtMatmulPreference_t pref_{nullptr};
-  cublasLtHandle_t handle_{nullptr};
-  cublasLtMatmulDesc_t matmul_desc_{nullptr};
-  cublasLtMatrixLayout_t a_desc_{nullptr};
-  cublasLtMatrixLayout_t b_desc_{nullptr};
-  cublasLtMatrixLayout_t c_desc_{nullptr};
-  cublasLtMatrixLayout_t out_desc_{nullptr};
-  cublasLtMatmulHeuristicResult_t heuristic_;
-};
-
-} // namespace cu
-
 namespace {
 
 std::tuple<bool, int64_t, array>
@@ -353,10 +79,25 @@ void Matmul::eval_gpu(const std::vector<array>& inputs, array& out) {
     batch_shape = {1};
   }
 
+  if (cu::can_use_gemv(M, N, K, a_transposed, b_transposed)) {
+    cu::gemv(
+        a,
+        b,
+        out,
+        M,
+        N,
+        K,
+        batch_count,
+        batch_shape,
+        a_batch_strides,
+        b_batch_strides,
+        encoder);
+    return;
+  }
+
   /////////////////////////////////////////////////////////////////////////////
   // Invoke cublasLt
-
+  cu::Matmul matmul(
-  cu::MatMul matmul(
       cu::device(s.device),
       a.dtype(),
       a_transposed,
@@ -371,27 +112,13 @@ void Matmul::eval_gpu(const std::vector<array>& inputs, array& out) {
       a_batch_strides.back(),
       b_batch_strides.back());
 
-  encoder.set_input_array(a);
+  if ((batch_count / batch_shape.back()) == 1) {
-  encoder.set_input_array(b);
+    matmul.run(encoder, out, a, b);
-  encoder.set_output_array(out);
-  auto nbatch = batch_count / batch_shape.back();
-  if (nbatch == 1) {
-    matmul.run(encoder, out.data<int8_t>(), a.data<int8_t>(), b.data<int8_t>());
     return;
   }
 
-  ContiguousIterator a_it(batch_shape, a_batch_strides, batch_shape.size() - 1);
+  matmul.run_batched(
-  ContiguousIterator b_it(batch_shape, b_batch_strides, batch_shape.size() - 1);
+      encoder, out, a, b, batch_shape, a_batch_strides, b_batch_strides);
-  auto concurrent = encoder.concurrent_context();
-  for (size_t i = 0; i < nbatch; ++i) {
-    matmul.run(
-        encoder,
-        out.data<int8_t>() + out.itemsize() * i * batch_shape.back() * M * N,
-        a.data<int8_t>() + a.itemsize() * a_it.loc,
-        b.data<int8_t>() + b.itemsize() * b_it.loc);
-    a_it.step();
-    b_it.step();
-  }
 }
 
 void AddMM::eval_gpu(const std::vector<array>& inputs, array& out) {
@@ -459,7 +186,7 @@ void AddMM::eval_gpu(const std::vector<array>& inputs, array& out) {
   /////////////////////////////////////////////////////////////////////////////
   // Invoke cublasLt
 
-  cu::MatMul matmul(
+  cu::Matmul matmul(
       cu::device(s.device),
       a.dtype(),
       a_transposed,
@@ -476,41 +203,22 @@ void AddMM::eval_gpu(const std::vector<array>& inputs, array& out) {
       b_batch_strides.back(),
       c_batch_strides.back());
 
-  encoder.set_input_array(a);
+  if ((batch_count / batch_shape.back()) == 1) {
-  encoder.set_input_array(b);
+    matmul.run(encoder, out, a, b, c, alpha_, beta_);
-  encoder.set_input_array(c);
-  encoder.set_output_array(out);
-
-  auto nbatch = batch_count / batch_shape.back();
-  if (nbatch == 1) {
-    matmul.run(
-        encoder,
-        out.data<int8_t>(),
-        a.data<int8_t>(),
-        b.data<int8_t>(),
-        c.data<int8_t>(),
-        alpha_,
-        beta_);
     return;
   }
-
+  matmul.run_batched(
-  ContiguousIterator a_it(batch_shape, a_batch_strides, batch_shape.size() - 1);
+      encoder,
-  ContiguousIterator b_it(batch_shape, b_batch_strides, batch_shape.size() - 1);
+      out,
-  ContiguousIterator c_it(batch_shape, c_batch_strides, batch_shape.size() - 1);
+      a,
-  auto concurrent = encoder.concurrent_context();
+      b,
-  for (size_t i = 0; i < nbatch; ++i) {
+      c,
-    matmul.run(
+      batch_shape,
-        encoder,
+      a_batch_strides,
-        out.data<int8_t>() + out.itemsize() * i * batch_shape.back() * M * N,
+      b_batch_strides,
-        a.data<int8_t>() + a.itemsize() * a_it.loc,
+      c_batch_strides,
-        b.data<int8_t>() + b.itemsize() * b_it.loc,
+      alpha_,
-        c.data<int8_t>() + c.itemsize() * c_it.loc,
+      beta_);
-        alpha_,
-        beta_);
-    a_it.step();
-    b_it.step();
-    c_it.step();
-  }
 }
 
 } // namespace mlx::core

mlx/backend/cuda/primitives.cu

@@ -71,7 +71,6 @@ bool fast::ScaledDotProductAttention::use_fallback(
   }
 
 NO_GPU(BlockMaskedMM)
-NO_GPU(Convolution)
 NO_GPU(DynamicSlice)
 NO_GPU(DynamicSliceUpdate)
 NO_GPU(FFT)

mlx/backend/cuda/rms_norm.cu

@@ -1,7 +1,6 @@
 // Copyright © 2025 Apple Inc.
 
 #include "mlx/backend/cuda/device.h"
-#include "mlx/backend/cuda/iterators/strided_iterator.cuh"
 #include "mlx/backend/cuda/kernel_utils.cuh"
 #include "mlx/backend/cuda/reduce/reduce.cuh"
 #include "mlx/backend/gpu/copy.h"
@@ -89,7 +88,7 @@ __global__ void rms_norm(
     T xn[N_READS];
     T wn[N_READS];
     cub::LoadDirectBlocked(index, x, xn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
     for (int i = 0; i < N_READS; ++i) {
       float norm = static_cast<float>(xn[i]) * normalizer;
       xn[i] = wn[i] * static_cast<T>(norm);
@@ -132,7 +131,7 @@ __global__ void rms_norm_vjp(
     auto index = r * BLOCK_DIM + block.thread_rank();
     cub::LoadDirectBlocked(index, x, xn, axis_size, cast_to<T>(0));
     cub::LoadDirectBlocked(index, g, gn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
     for (int i = 0; i < N_READS; i++) {
       float t = static_cast<float>(xn[i]);
       float wi = wn[i];
@@ -154,7 +153,7 @@ __global__ void rms_norm_vjp(
     T gn[N_READS];
     cub::LoadDirectBlocked(index, x, xn, axis_size);
     cub::LoadDirectBlocked(index, g, gn, axis_size);
-    cub::LoadDirectBlocked(index, strided_iterator(w, w_stride), wn, axis_size);
+    cub::LoadDirectBlocked(index, StridedIterator(w, w_stride), wn, axis_size);
     for (int i = 0; i < N_READS; i++) {
       float xi = xn[i];
       float wi = wn[i];

mlx/backend/cuda/ternary.cu

@@ -76,7 +76,7 @@ __global__ void ternary_g(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto [a_idx, b_idx, c_idx] = elem_to_loc_4d(
+    auto [a_idx, b_idx, c_idx] = elem_to_loc(
         index,
         shape.data(),
         a_strides.data(),

mlx/backend/cuda/unary.cu

@@ -3,7 +3,6 @@
 #include "mlx/backend/common/unary.h"
 #include "mlx/backend/cuda/device.h"
 #include "mlx/backend/cuda/device/unary_ops.cuh"
-#include "mlx/backend/cuda/iterators/general_iterator.cuh"
 #include "mlx/backend/cuda/kernel_utils.cuh"
 #include "mlx/dtype_utils.h"
 #include "mlx/primitives.h"
@@ -48,7 +47,7 @@ __global__ void unary_g(
     int ndim) {
   IdxT index = cg::this_grid().thread_rank();
   if (index < size) {
-    auto idx = elem_to_loc_4d(index, shape.data(), strides.data(), ndim);
+    auto idx = elem_to_loc(index, shape.data(), strides.data(), ndim);
     out[index] = Op{}(in[idx]);
   }
 }

mlx/backend/cuda/utils.cpp

@@ -17,6 +17,14 @@ CudaStream::~CudaStream() {
   CHECK_CUDA_ERROR(cudaStreamDestroy(stream_));
 }
 
+void check_cublas_error(const char* name, cublasStatus_t err) {
+  if (err != CUBLAS_STATUS_SUCCESS) {
+    // TODO: Use cublasGetStatusString when it is widely available.
+    throw std::runtime_error(
+        fmt::format("{} failed with code: {}.", name, static_cast<int>(err)));
+  }
+}
+
 void check_cuda_error(const char* name, cudaError_t err) {
   if (err != cudaSuccess) {
     throw std::runtime_error(

mlx/backend/cuda/utils.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <cublasLt.h>
 #include <cuda.h>
 #include <cuda_runtime.h>
 
@@ -33,10 +34,12 @@ class CudaStream {
 };
 
 // Throw exception if the cuda API does not succeed.
+void check_cublas_error(const char* name, cublasStatus_t err);
 void check_cuda_error(const char* name, cudaError_t err);
 void check_cuda_error(const char* name, CUresult err);
 
 // The macro version that prints the command that failed.
+#define CHECK_CUBLAS_ERROR(cmd) check_cublas_error(#cmd, (cmd))
 #define CHECK_CUDA_ERROR(cmd) check_cuda_error(#cmd, (cmd))
 
 // Convert Dtype to CUDA C++ types.

mlx/backend/cuda/worker.cpp

@@ -1,7 +1,6 @@
 // Copyright © 2025 Apple Inc.
 
 #include "mlx/backend/cuda/worker.h"
-#include "mlx/backend/cuda/allocator.h"
 #include "mlx/backend/cuda/device.h"
 
 namespace mlx::core::cu {
@@ -12,10 +11,10 @@ Worker::Worker()
 
 Worker::~Worker() {
   {
-    std::lock_guard lock(worker_mutex_);
+    std::lock_guard lock(mtx_);
     stop_ = true;
   }
-  worker_event_.signal(batch_ + 1);
+  cond_.notify_one();
   worker_.join();
 }
 
@@ -23,53 +22,41 @@ void Worker::add_task(std::function<void()> task) {
   pending_tasks_.push_back(std::move(task));
 }
 
-void Worker::consume_in_this_thread() {
+void Worker::signal(void* data) {
-  for (auto& task : pending_tasks_) {
+  auto w = static_cast<Worker*>(data);
-    task();
-  }
-  pending_tasks_.clear();
-}
-
-void Worker::end_batch() {
-  batch_++;
   {
-    std::lock_guard lock(worker_mutex_);
+    std::lock_guard lock(w->mtx_);
-    worker_tasks_[batch_] = std::move(pending_tasks_);
+    w->signaled_batch_++;
   }
-  uncommited_batches_++;
+  w->cond_.notify_one();
-}
-
-void Worker::commit() {
-  if (uncommited_batches_ == 0) {
-    return;
-  }
-  uncommited_batches_ = 0;
-  worker_event_.signal(batch_);
 }
 
 void Worker::commit(cudaStream_t stream) {
-  if (uncommited_batches_ == 0) {
+  // Move pending tasks into tasks
+  if (pending_tasks_.empty()) {
     return;
   }
-  uncommited_batches_ = 0;
+  {
-  // Signal the |worker_event_| in |signal_stream_| after the kernels in
+    std::lock_guard lock(mtx_);
-  // |stream_| finish running.
+    // Move pending tasks into ready tasks
+    worker_tasks_[++committed_batch_] = std::move(pending_tasks_);
+  }
   signal_event_.record(stream);
   signal_event_.wait(signal_stream_);
-  worker_event_.signal(signal_stream_, batch_);
+  cudaLaunchHostFunc(signal_stream_, signal, this);
 }
 
 void Worker::thread_fn() {
-  // The worker thread is safe to free buffers.
-  allocator().register_this_thread();
-
   while (!stop_) {
-    uint64_t batch = worker_event_.value();
+    uint64_t current_batch = 0;
     Tasks tasks;
     {
-      std::lock_guard lock(worker_mutex_);
+      std::unique_lock<std::mutex> lk(mtx_);
-      // Move tasks in signaled batches.
+      cond_.wait(lk, [this, &current_batch] {
-      auto end = worker_tasks_.upper_bound(batch);
+        return this->signaled_batch_ > current_batch || this->stop_;
+      });
+      current_batch = signaled_batch_;
+      auto end = worker_tasks_.upper_bound(current_batch);
       for (auto it = worker_tasks_.begin(); it != end; ++it) {
         if (tasks.empty()) {
           tasks = std::move(it->second);
@@ -85,7 +72,6 @@ void Worker::thread_fn() {
       auto task = std::move(tasks[i]);
       task();
     }
-    worker_event_.wait(batch + 1);
   }
 }
 

mlx/backend/cuda/worker.h

@@ -5,6 +5,7 @@
 #include "mlx/backend/cuda/event.h"
 #include "mlx/backend/cuda/utils.h"
 
+#include <condition_variable>
 #include <functional>
 #include <map>
 #include <mutex>
@@ -24,38 +25,24 @@ class Worker {
   // Add a pending |task| that will run when consumed or commited.
   void add_task(std::function<void()> task);
 
-  // Run pending tasks immediately in current thread.
-  void consume_in_this_thread();
-
-  // Put pending tasks in a batch.
-  void end_batch();
-
-  // Inform worker thread to run current batches now.
-  void commit();
-
   // Inform worker thread to run current batches after kernels in |stream|
   // finish running.
   void commit(cudaStream_t stream);
 
-  // Return how many batches have been added but not committed yet.
-  size_t uncommited_batches() const {
-    return uncommited_batches_;
-  }
-
  private:
-  void thread_fn();
+  static void signal(void*);
 
-  uint64_t batch_{0};
+  void thread_fn();
-  size_t uncommited_batches_{0};
+  std::mutex mtx_;
+  std::condition_variable cond_;
+
+  uint64_t committed_batch_{0};
+  uint64_t signaled_batch_{0};
 
   // Cuda stream and event for signaling kernel completion.
   CudaStream signal_stream_;
   CudaEvent signal_event_;
 
-  // Worker thread.
-  SharedEvent worker_event_;
-  std::thread worker_;
-  std::mutex worker_mutex_;
   bool stop_{false};
 
   // Tasks are put in |pending_tasks_| first, and then moved to
@@ -63,6 +50,7 @@ class Worker {
   using Tasks = std::vector<std::function<void()>>;
   Tasks pending_tasks_;
   std::map<uint64_t, Tasks> worker_tasks_;
+  std::thread worker_;
 };
 
 } // namespace mlx::core::cu

mlx/backend/metal/allocator.cpp

@@ -128,8 +128,7 @@ Buffer MetalAllocator::malloc(size_t size) {
 
     auto pool = metal::new_scoped_memory_pool();
 
-    // If we have a lot of memory pressure or are over the maximum cache size,
+    // If we have a lot of memory pressure try to reclaim memory from the cache
-    // try to reclaim memory from the cache
     if (mem_required >= gc_limit_ || num_resources_ >= resource_limit_) {
       num_resources_ -=
           buffer_cache_.release_cached_buffers(mem_required - gc_limit_);

mlx/backend/metal/event.cpp

@@ -14,6 +14,10 @@ Event::Event(Stream stream) : stream_(stream) {
   auto p = metal::new_scoped_memory_pool();
   event_ = std::shared_ptr<void>(
       metal::device(Device::gpu).mtl_device()->newSharedEvent(), dtor);
+  if (event_ == nullptr) {
+    throw std::runtime_error(
+        "[Event::Event] Failed to create Metal shared event.");
+  }
 }
 
 void Event::wait() {

mlx/backend/metal/quantized.cpp

@@ -265,9 +265,15 @@ void qvm_split_k(
   MTL::Size group_dims = MTL::Size(bk, 2, 1);
   MTL::Size grid_dims = MTL::Size(M, N / bn, B);
 
-  int x_batch_ndims = x.ndim() - 2;
   auto x_shape = x.shape();
   auto x_strides = x.strides();
+  if (x_shape.size() == 1) {
+    x_shape.insert(x_shape.begin(), 1);
+    x_strides.insert(x_strides.begin(), 0);
+  }
+
+  int x_ndim = x_shape.size();
+  int x_batch_ndims = x_ndim - 2;
   int w_batch_ndims = w.ndim() - 2;
   auto w_shape = w.shape();
   auto w_strides = w.strides();
@@ -278,7 +284,7 @@ void qvm_split_k(
   x_shape.insert(x_shape.end() - 2, split_k);
   x_shape.back() /= split_k;
   x_strides.insert(x_strides.end() - 2, split_D);
-  x_strides[x.ndim() - 1] = split_D;
+  x_strides[x_ndim - 1] = split_D;
   x_batch_ndims += 1;
 
   w_shape.insert(w_shape.end() - 2, split_k);
@@ -291,6 +297,9 @@ void qvm_split_k(
   int final_block_size = K - (split_k - 1) * split_D;
 
   auto temp_shape = out.shape();
+  if (temp_shape.size() == 1) {
+    temp_shape.insert(temp_shape.begin(), 1);
+  }
   temp_shape.insert(temp_shape.end() - 2, split_k);
   array intermediate(temp_shape, x.dtype(), nullptr, {});
   intermediate.set_data(allocator::malloc(intermediate.nbytes()));

mlx/fast.cpp

@@ -708,7 +708,10 @@ array scaled_dot_product_attention(
       }
       if (mask.dtype() == bool_) {
         scores = where(
-            mask, scores, array(finfo(scores.dtype()).min, scores.dtype()));
+            mask,
+            scores,
+            array(-std::numeric_limits<float>::infinity(), scores.dtype()),
+            s);
       } else {
         scores = add(scores, mask, s);
       }

mlx/primitives.cpp

@@ -1271,19 +1271,6 @@ std::vector<array> Convolution::vjp(
         has_neg_padding |= (pd < 0);
       }
 
-      auto padding_lo_ = std::vector<int>(padding_lo);
-      auto padding_hi_ = std::vector<int>(padding_hi);
-
-      // Use negative padding on the gradient output
-      if (has_neg_padding) {
-        for (auto& p : padding_lo_) {
-          p = std::max(0, p);
-        }
-        for (auto& p : padding_hi_) {
-          p = std::max(0, p);
-        }
-      }
-
       auto wt_trans = group_transpose(wt, 0, 1, -1);
       auto grad = conv_general(
           /* const array& input = */ cotan,
@@ -1305,12 +1292,9 @@ std::vector<array> Convolution::vjp(
         for (int i = 0; i < grad.ndim() - 2; i++) {
           if (padding_lo[i] < 0) {
             starts[i + 1] -= padding_lo[i];
-            padding_lo[i] = 0;
           }
-
           if (padding_hi[i] < 0) {
             stops[i + 1] += padding_hi[i];
-            padding_hi[i] = 0;
           }
         }
 

mlx/transforms.cpp

@@ -72,7 +72,12 @@ array eval_impl(std::vector<array> outputs, bool async) {
 
   // Stream events for synchronization after eval
   std::unordered_map<uint32_t, Event> events;
-  events.emplace(stream.index, Event{stream});
+  {
+    auto e = Event{stream};
+    e.set_value(1);
+    synchronizer.attach_event(e);
+    events.emplace(stream.index, std::move(e));
+  }
 
   {
     // Record the degree of each input
@@ -184,21 +189,26 @@ array eval_impl(std::vector<array> outputs, bool async) {
     }
   }
 
+  std::unordered_set<int> open_streams;
+
   while (!tape.empty()) {
     auto arr = std::move(tape.back());
     tape.pop_back();
 
     auto stream = arr.primitive().stream();
+    open_streams.insert(stream.index);
 
-    // Lookup corresponding event
+    if (async) {
-    auto e = events.find(stream.index);
+      // Lookup corresponding event
-    if (e == events.end()) {
+      auto e = events.find(stream.index);
-      e = events.emplace(stream.index, Event{stream}).first;
+      if (e == events.end()) {
-    }
+        e = events.emplace(stream.index, Event{stream}).first;
-    e->second.set_value(1);
+      }
-    arr.attach_event(e->second);
+      e->second.set_value(1);
-    for (auto& s : arr.siblings()) {
+      arr.attach_event(e->second);
-      s.attach_event(e->second);
+      for (auto& s : arr.siblings()) {
+        s.attach_event(e->second);
+      }
     }
 
     for (auto& in : arr.inputs()) {
@@ -227,9 +237,10 @@ array eval_impl(std::vector<array> outputs, bool async) {
         (get_active_memory() > get_memory_limit() &&
          scheduler::n_active_tasks() > 0)) {
       // Commit any open streams
-      for (auto& [_, e] : events) {
+      for (auto i : open_streams) {
-        if (e.stream().device == Device::gpu) {
+        auto s = get_stream(i);
-          gpu::finalize(e.stream());
+        if (s.device == Device::gpu) {
+          gpu::finalize(s);
         }
       }
       scheduler::wait_for_one();
@@ -263,9 +274,11 @@ array eval_impl(std::vector<array> outputs, bool async) {
   }
 
   // Signal the event in its stream
-  for (auto& [_, e] : events) {
+  for (auto i : open_streams) {
-    auto s = e.stream();
+    auto s = get_stream(i);
-    e.signal(s);
+    if (auto e = events.find(i); e != events.end()) {
+      e->second.signal(s);
+    }
     if (s.device == Device::gpu) {
       gpu::finalize(s);
     }
@@ -302,7 +315,7 @@ void eval(std::vector<array> outputs) {
     return;
   }
 
-  eval_impl(std::move(outputs), false).event().wait();
+  eval_impl(std::move(outputs), false).wait();
 }
 
 std::pair<std::vector<array>, std::vector<array>> vjp(

python/mlx/optimizers/optimizers.py

@@ -477,7 +477,7 @@ class Adam(Optimizer):
 
         m_{t+1} &= \beta_1 m_t + (1 - \beta_1) g_t \\
         v_{t+1} &= \beta_2 v_t + (1 - \beta_2) g_t^2 \\
-        w_{t+1} &= w_t - \lambda \frac{m_{t+1}}{\sqrt{v_{t+1} + \epsilon}}
+        w_{t+1} &= w_t - \lambda \frac{m_{t+1}}{\sqrt{v_{t+1}} + \epsilon}
 
     Args:
         learning_rate (float or callable): The learning rate :math:`\lambda`.
@@ -546,7 +546,7 @@ class AdamW(Adam):
 
         m_{t+1} &= \beta_1 m_t + (1 - \beta_1) g_t \\
         v_{t+1} &= \beta_2 v_t + (1 - \beta_2) g_t^2 \\
-        w_{t+1} &= w_t - \alpha (\frac{m_{t+1}}{\sqrt{v_{t+1} + \epsilon}} + \lambda w_t)
+        w_{t+1} &= w_t - \alpha (\frac{m_{t+1}}{\sqrt{v_{t+1}} + \epsilon} + \lambda w_t)
 
     Args:
         learning_rate (float or callable): The learning rate :math:`\alpha`.

python/scripts/repair_cuda.sh

@@ -1,9 +1,10 @@
 #!/bin/bash
 
 auditwheel repair dist/* \
-  --plat manylinux_2_39_x86_64 \
+  --plat manylinux_2_35_x86_64 \
   --exclude libcublas* \
   --exclude libnvrtc* \
+  --exclude libcuda* \
   -w wheel_tmp
 
 
@@ -15,7 +16,7 @@ rm "${repaired_wheel}"
 mlx_so="mlx/lib/libmlx.so"
 rpath=$(patchelf --print-rpath "${mlx_so}")
 base="\$ORIGIN/../../nvidia"
-rpath=$rpath:${base}/cublas/lib:${base}/cuda_nvrtc/lib
+rpath=$rpath:${base}/cublas/lib:${base}/cuda_nvrtc/lib:${base}/cudnn/lib
 patchelf --force-rpath --set-rpath "$rpath" "$mlx_so"
 python ../python/scripts/repair_record.py ${mlx_so}
 

python/scripts/repair_linux.sh

@@ -2,6 +2,7 @@
 
 auditwheel repair dist/* \
   --plat manylinux_2_35_x86_64 \
+  --only-plat \
   --exclude libmlx* \
   -w wheel_tmp
 

python/src/ops.cpp

@@ -4022,8 +4022,9 @@ void init_ops(nb::module_& m) {
         Args:
             file (file, str): File in which the array is saved.
             arrays (dict(str, array)): The dictionary of names to arrays to
-            be saved. metadata (dict(str, str), optional): The dictionary of
+              be saved.
-            metadata to be saved.
+            metadata (dict(str, str), optional): The dictionary of
+              metadata to be saved.
       )pbdoc");
   m.def(
       "save_gguf",
@@ -4258,7 +4259,7 @@ void init_ops(nb::module_& m) {
 
         .. math::
 
-          w_i = s \hat{w_i} - \beta
+          w_i = s \hat{w_i} + \beta
 
         Args:
           w (array): Matrix to be quantized

python/tests/cuda_skip.py

@@ -15,19 +15,12 @@ cuda_skip = {
     "TestOps.test_hadamard_grad_vmap",
     # Convolutions NYI
     "TestConv.test_1d_conv_with_2d",
-    "TestConv.test_asymmetric_padding",
-    "TestConv.test_basic_grad_shapes",
-    "TestConv.test_conv2d_unaligned_channels",
     "TestConv.test_conv_1d_groups_flipped",
     "TestConv.test_conv_general_flip_grad",
     "TestConv.test_conv_groups_grad",
-    "TestConv.test_numpy_conv",
-    "TestConv.test_repeated_conv",
-    "TestConv.test_torch_conv_1D",
     "TestConv.test_torch_conv_1D_grad",
     "TestConv.test_torch_conv_2D",
     "TestConv.test_torch_conv_2D_grad",
-    "TestConv.test_torch_conv_3D",
     "TestConv.test_torch_conv_3D_grad",
     "TestConv.test_torch_conv_depthwise",
     "TestConv.test_torch_conv_general",
@@ -40,10 +33,6 @@ cuda_skip = {
     "TestConvTranspose.test_torch_conv_transpose_3D",
     "TestConvTranspose.test_torch_conv_transpose_3D_grad",
     "TestConvTranspose.test_torch_conv_transpose_3d_output_padding",
-    "TestExportImport.test_export_conv",
-    "TestLayers.test_conv1d",
-    "TestLayers.test_conv2d",
-    "TestVmap.test_vmap_conv",
     # FFTs NYI
     "TestFFT.test_fft",
     "TestFFT.test_fft_big_powers_of_two",

python/tests/test_fast_sdpa.py

@@ -398,6 +398,18 @@ class TestFastSDPA(mlx_tests.MLXTestCase):
             )
             self.assertTrue(mx.allclose(ref, out, atol=1e-4, rtol=1e-4))
 
+    def test_fully_masked(self):
+        Lkv = 8
+        mask = mx.array(False)
+        for D in [4, 128]:
+            for Lq in [1, 8]:
+                q = mx.random.normal(shape=(1, 4, Lq, D))
+                k = mx.random.normal(shape=(1, 4, Lkv, D))
+                v = mx.random.normal(shape=(1, 4, Lkv, D))
+
+                out = mx.fast.scaled_dot_product_attention(q, k, v, mask=mask, scale=1)
+                self.assertTrue(mx.all(mx.isnan(out)))
+
     def test_fast_sdpa_few_query(self):
         D = 64
         L = 43

python/tests/test_quantized.py

@@ -220,6 +220,19 @@ class TestQuantized(mlx_tests.MLXTestCase):
                 self.assertEqual(y_q.shape, y_hat.shape)
                 self.assertLess((y_q - y_hat).abs().max(), 2e-3)
 
+        # Test with 1D vector
+        group_size = 32
+        bits = 8
+        N = 2048
+        x = 1e-1 * mx.random.normal(shape=(N,), key=k1)
+        w = 1e-1 * mx.random.normal(shape=(N, N), key=k2)
+        w_q, scales, biases = mx.quantize(w, group_size, bits)
+        w_hat = mx.dequantize(w_q, scales, biases, group_size, bits)
+        y_q = mx.quantized_matmul(x, w_q, scales, biases, False, group_size, bits)
+        y_hat = x @ w_hat
+        self.assertEqual(y_q.shape, y_hat.shape)
+        self.assertLess((y_q - y_hat).abs().max(), 2e-3)
+
     def test_throw(self):
         x = mx.random.normal(shape=(10, 512))
         w = mx.random.normal(shape=(32, 512))

setup.py

@@ -9,7 +9,7 @@ from functools import partial
 from pathlib import Path
 from subprocess import run
 
-from setuptools import Command, Extension, setup
+from setuptools import Command, Extension, find_namespace_packages, setup
 from setuptools.command.bdist_wheel import bdist_wheel
 from setuptools.command.build_ext import build_ext
 
@@ -166,6 +166,10 @@ class GenerateStubs(Command):
         # Run again without recursive to specify output file name
         subprocess.run(["rm", f"{out_path}/mlx.pyi"])
         subprocess.run(stub_cmd + ["-o", f"{out_path}/__init__.pyi"])
+        # mx.bool_ gets filtered by nanobind because of the trailing
+        # underscore, add it manually:
+        with open(f"{out_path}/__init__.pyi", "a") as fid:
+            fid.write("\nbool_: Dtype = ...")
 
 
 class MLXBdistWheel(bdist_wheel):
@@ -184,19 +188,23 @@ with open(Path(__file__).parent / "README.md", encoding="utf-8") as f:
 
 if __name__ == "__main__":
     package_dir = {"": "python"}
-    packages = [
+    packages = find_namespace_packages(
-        "mlx",
+        where="python",
-        "mlx.nn",
+        exclude=[
-        "mlx.nn.layers",
+            "src",
-        "mlx.optimizers",
+            "tests",
-    ]
+            "scripts",
+            "mlx.lib",
+            "mlx.include",
+            "mlx.share",
+            "mlx.share.**",
+            "mlx.include.**",
+        ],
+    )
 
     build_macos = platform.system() == "Darwin"
     build_cuda = "MLX_BUILD_CUDA=ON" in os.environ.get("CMAKE_ARGS", "")
 
-    install_requires = []
-    if build_cuda:
-        install_requires = ["nvidia-cublas-cu12", "nvidia-cuda-nvrtc-cu12"]
     version = get_version()
 
     _setup = partial(
@@ -221,7 +229,7 @@ if __name__ == "__main__":
         },
     )
 
-    package_data = {"mlx": ["lib/*", "include/*", "share/*"], "mlx.core": ["*.pyi"]}
+    package_data = {"mlx.core": ["*.pyi"]}
 
     extras = {
         "dev": [
@@ -239,6 +247,7 @@ if __name__ == "__main__":
             "mlx.distributed_config = mlx.distributed_run:distributed_config",
         ]
     }
+    install_requires = []
 
     # Release builds for PyPi are in two stages.
     # Each stage should be run from a clean build:
@@ -258,11 +267,11 @@ if __name__ == "__main__":
     #  - Package name is back-end specific, e.g mlx-metal
     if build_stage != 2:
         if build_stage == 1:
-            if build_macos:
+            install_requires.append(
-                install_requires += [f"mlx-metal=={version}"]
+                f'mlx-metal=={version}; platform_system == "Darwin"'
-            else:
+            )
-                extras["cuda"] = [f"mlx-cuda=={version}"]
+            extras["cuda"] = [f'mlx-cuda=={version}; platform_system == "Linux"']
-                extras["cpu"] = [f"mlx-cpu=={version}"]
+            extras["cpu"] = [f'mlx-cpu=={version}; platform_system == "Linux"']
 
         _setup(
             name="mlx",
@@ -277,9 +286,15 @@ if __name__ == "__main__":
             name = "mlx-metal"
         elif build_cuda:
             name = "mlx-cuda"
+            install_requires += [
+                "nvidia-cublas-cu12==12.9.*",
+                "nvidia-cuda-nvrtc-cu12==12.9.*",
+                "nvidia-cudnn-cu12==12.9.*",
+            ]
         else:
             name = "mlx-cpu"
         _setup(
             name=name,
             packages=["mlx"],
+            install_requires=install_requires,
         )