vllm/csrc/quantization/cutlass_w8a8/scaled_mm_c3x.cu

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#include <cudaTypedefs.h>
#include "c3x/scaled_mm_kernels.hpp"
#include "cuda_utils.h"
/*
This file defines quantized GEMM operations using the CUTLASS 3.x API, for
NVIDIA GPUs with sm90a (Hopper) or later.
*/
void cutlass_scaled_mm_sm90(torch::Tensor& c, torch::Tensor const& a,
torch::Tensor const& b,
torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
std::optional<torch::Tensor> const& bias) {
TORCH_CHECK(a_scales.dtype() == torch::kFloat32);
TORCH_CHECK(b_scales.dtype() == torch::kFloat32);
int M = a.size(0), N = b.size(1), K = a.size(1);
if ((a_scales.numel() == 1 || a_scales.numel() == a.size(0)) &&
(b_scales.numel() == 1 || b_scales.numel() == b.size(1))) {
// Standard per-tensor/per-token/per-channel scaling
TORCH_CHECK(a_scales.is_contiguous() && b_scales.is_contiguous());
if (a.dtype() == torch::kFloat8_e4m3fn) {
vllm::cutlass_scaled_mm_sm90_fp8(c, a, b, a_scales, b_scales, bias);
} else {
TORCH_CHECK(a.dtype() == torch::kInt8);
vllm::cutlass_scaled_mm_sm90_int8(c, a, b, a_scales, b_scales, bias);
}
} else {
using GroupShape = std::array<int64_t, 2>;
auto make_group_shape = [](torch::Tensor const& x,
torch::Tensor const& s) -> GroupShape {
TORCH_CHECK(s.dim() == 2, "cutlass_scaled_mm group scales must be 2D");
return {cuda_utils::ceil_div(x.size(0), s.size(0)),
cuda_utils::ceil_div(x.size(1), s.size(1))};
};
GroupShape a_scale_group_shape = make_group_shape(a, a_scales);
GroupShape b_scale_group_shape = make_group_shape(b, b_scales);
// 1x128 per-token group scales for activations
// 128x128 blockwise scales for weights
TORCH_CHECK((a_scale_group_shape == GroupShape{1, 128} &&
b_scale_group_shape == GroupShape{128, 128} &&
a.dtype() == torch::kFloat8_e4m3fn &&
b.dtype() == torch::kFloat8_e4m3fn),
"cutlass_scaled_mm only supports datatype float8_e4m3fn.\n"
"a_scale_group_shape must be [1, 128]. Got: [",
a_scale_group_shape[0], ", ", a_scale_group_shape[1],
"]\n"
"b_scale_group_shape must be [128, 128]. Got: [",
b_scale_group_shape[0], ", ", b_scale_group_shape[1], "]");
TORCH_CHECK(!bias, "Bias not yet supported blockwise scaled_mm");
vllm::cutlass_scaled_mm_blockwise_sm90_fp8(c, a, b, a_scales, b_scales);
}
}
void cutlass_scaled_mm_azp_sm90(torch::Tensor& out, torch::Tensor const& a,
torch::Tensor const& b,
torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
torch::Tensor const& azp_adj,
std::optional<torch::Tensor> const& azp,
std::optional<torch::Tensor> const& bias) {
TORCH_CHECK(a_scales.dtype() == torch::kFloat32);
TORCH_CHECK(b_scales.dtype() == torch::kFloat32);
vllm::cutlass_scaled_mm_azp_sm90_int8(out, a, b, a_scales, b_scales, azp_adj,
azp, bias);
}
#if defined CUDA_VERSION && CUDA_VERSION >= 12080
void cutlass_scaled_mm_sm100(torch::Tensor& c, torch::Tensor const& a,
torch::Tensor const& b,
torch::Tensor const& a_scales,
torch::Tensor const& b_scales,
std::optional<torch::Tensor> const& bias) {
TORCH_CHECK(a_scales.dtype() == torch::kFloat32);
TORCH_CHECK(b_scales.dtype() == torch::kFloat32);
int M = a.size(0), N = b.size(1), K = a.size(1);
TORCH_CHECK(
(a_scales.numel() == 1 || a_scales.numel() == a.size(0)) &&
(b_scales.numel() == 1 || b_scales.numel() == b.size(1)),
"Currently, block scaled fp8 gemm is not implemented for Blackwell");
// Standard per-tensor/per-token/per-channel scaling
TORCH_CHECK(a_scales.is_contiguous() && b_scales.is_contiguous());
TORCH_CHECK(a.dtype() == torch::kFloat8_e4m3fn,
"Currently, only fp8 gemm is implemented for Blackwell");
vllm::cutlass_scaled_mm_sm100_fp8(c, a, b, a_scales, b_scales, bias);
}
#endif