[CUDA] More sizes for gemv (#2429)

* route more to gemv

* route more sizes to custom gemv
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Awni Hannun 2025-07-28 12:35:01 -07:00 committed by GitHub
parent 1588659062
commit ab0e608862
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@ -11,7 +11,6 @@ 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>
@ -74,8 +73,23 @@ __global__ void gemv_batched(
}
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));
bool is_multiple = K % 32 == 0 || K % 64 == 0 || K % 128 == 0;
return is_multiple && ((M == 1 && b_transposed) || (N == 1 && !a_transposed));
}
template <typename F>
void dispatch_n_per_thread(int n_per_thread, F&& f) {
switch (n_per_thread) {
case 1:
f(std::integral_constant<int, 1>{});
break;
case 2:
f(std::integral_constant<int, 2>{});
break;
case 4:
f(std::integral_constant<int, 4>{});
break;
}
}
void gemv(
@ -114,33 +128,39 @@ void gemv(
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());
int n_per_t = 4;
while (K % (n_per_t * WARP_SIZE) != 0) {
n_per_t >>= 1;
}
dispatch_n_per_thread(n_per_t, [&](auto n_per_thread) {
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());
}
});
});
}