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AstrAI/csrc/kernels/fp8/common.h
T
ViperEkura 31ca357c61 refactor: namespace csrc kernels and extract common helpers
- attention family -> astrai::attention; fp8 family -> astrai::fp8
- new common/reduce.cuh (warp/group reductions, atomic_max_float)
- new common/cp_async.cuh (predicated cp_async_16, commit/wait group)
- move MAX_SPLITS into attention/common.h; delete warp_utils.cuh
- .cu bindings and pure C tests open family namespaces via using
2026-08-24 14:49:55 +08:00

76 lines
2.7 KiB
C++

#pragma once
#include <cuda_bf16.h>
#include <cuda_fp8.h>
#include <cuda_runtime.h>
#include <cstdint>
// Pure POD/traits header — no .cuh/CUDA-kernel includes; raw __nv_* type
// spellings only.
namespace astrai {
namespace fp8 {
// Compile-time FP8 format: E4M3 (forward / high precision, max 448) or
// E5M2 (gradient / large dynamic range, max 57344).
enum class FP8Format : int {
E4M3 = 0,
E5M2 = 1,
};
// Compile-time tile configuration, mirroring KernelTraits<HEAD_DIM, BC,
// WARPS, STAGES> in the attention kernels. `Fmt` selects the FP8 conversion
// and the MMA PTX mnemonic; the remaining parameters shape the CTA tile and
// the cp.async pipeline depth.
template <FP8Format Fmt, int BlockM, int BlockN, int K, int Stages>
struct Fp8GemmTraits {
static constexpr FP8Format kFormat = Fmt;
static constexpr int kBlockM = BlockM;
static constexpr int kBlockN = BlockN;
static constexpr int kK = K;
static constexpr int kStages = Stages;
static constexpr bool kIsE5M2 = (Fmt == FP8Format::E5M2);
static constexpr __nv_fp8_interpretation_t kNvFormat =
kIsE5M2 ? __NV_E5M2 : __NV_E4M3;
static constexpr float kFp8Max = kIsE5M2 ? 57344.0f : 448.0f;
};
// Unified GEMM parameter POD, mirroring AttentionParams: one struct flows
// through quantize / fused / pre-quantized kernels. Each kernel touches only
// the fields it needs; buffers are raw pointers packed by the torch binding.
struct FP8Params {
// Inputs: a/b are BF16 for the fused (quantize-in-GEMM) path, FP8 for
// the pre-quantized path. Scales are quantization steps (device scalars).
const void* __restrict__ a_ptr;
const void* __restrict__ b_ptr;
const float* __restrict__ scale_a;
const float* __restrict__ scale_b;
// Output: BF16 or FP8 (E4M3). out_scale is the output quantization step
// (FP8 output only).
void* __restrict__ out_ptr;
const float* __restrict__ out_scale;
// Fused forward extras: bias (may be null) and amax slots (may be null).
const __nv_bfloat16* __restrict__ bias;
float* __restrict__ amax_a;
float* __restrict__ amax_b;
// Shapes. total is only used by the elementwise quantize kernel. `int`
// covers every realistic LLM shape; the kernels promote to int64 for all
// pointer arithmetic.
int m, n, k;
// Physical leading dimensions (column count, i.e. row stride) of A and B.
// For a non-transposed operand the stride equals the contract dim; for a
// transposed operand it is the operand's own column count. The binding
// packs these so the kernel reads both buffers either naturally or
// transposed depending on TransA/TransB.
int a_ld, b_ld;
int total;
};
} // namespace fp8
} // namespace astrai