Merge 4d68bd3250 into a6d780154f

mlx/backend/cuda/arg_reduce.cu

@@ -1,4 +1,5 @@
 // Copyright © 2025 Apple Inc.
+
 #include "mlx/backend/common/utils.h"
 #include "mlx/backend/cuda/device.h"
 #include "mlx/backend/cuda/iterators/strided_iterator.cuh"
@@ -112,7 +113,7 @@ __global__ void arg_reduce_general(
 
   for (int r = 0; r < cuda::ceil_div(axis_size, BLOCK_DIM * N_READS); ++r) {
     T vals[N_READS];
-    auto tid = r * BLOCK_DIM + block.thread_index().x;
+    auto tid = r * BLOCK_DIM + block.thread_index().z;
     cub::LoadDirectBlocked(
         tid, strided_iterator(in + in_idx, axis_stride), vals, axis_size, init);
     best = op.reduce_many(best, vals, tid * N_READS);
@@ -157,7 +158,7 @@ void ArgReduce::eval_gpu(const std::vector<array>& inputs, array& out) {
       constexpr uint32_t N_READS = 4;
       MLX_SWITCH_BLOCK_DIM(cuda::ceil_div(axis_size, N_READS), BLOCK_DIM, {
         dim3 num_blocks = get_2d_grid_dims(out.shape(), out.strides());
-        dim3 block_dims{BLOCK_DIM, 1, 1};
+        dim3 block_dims{1, 1, BLOCK_DIM};
         auto kernel = &cu::arg_reduce_general<
             InType,
             cu::ArgMax<InType>,

mlx/backend/cuda/matmul.cpp

@@ -5,7 +5,6 @@
 #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>
@@ -46,7 +45,7 @@ class MatMul {
     heuristic_.state = CUBLAS_STATUS_NOT_INITIALIZED;
 
     auto scale_type = dtype_to_cuda_type(dtype);
-    if (dtype == bfloat16 || dtype == float16) {
+    if (dtype == bfloat16) {
       scale_type = CUDA_R_32F;
     }
     CHECK_CUBLAS_ERROR(cublasLtMatmulDescCreate(
@@ -193,12 +192,11 @@ class MatMul {
   cublasComputeType_t dtype_to_compute_type(Dtype dtype) {
     switch (dtype) {
       case float16:
-        return CUBLAS_COMPUTE_32F;
+        return CUBLAS_COMPUTE_16F;
       case bfloat16:
         return CUBLAS_COMPUTE_32F;
       case float32:
-        return mlx::core::env::enable_tf32() ? CUBLAS_COMPUTE_32F_FAST_TF32
+        return CUBLAS_COMPUTE_32F;
-                                             : CUBLAS_COMPUTE_32F;
       case float64:
       case complex64:
         return CUBLAS_COMPUTE_64F;

mlx/utils.h

@@ -149,11 +149,6 @@ inline bool metal_fast_synch() {
   return metal_fast_synch;
 }
 
-inline bool enable_tf32() {
-  static bool enable_tf32_ = get_var("MLX_ENABLE_TF32", 1);
-  return enable_tf32_;
-}
-
 } // namespace env
 
 } // namespace mlx::core