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submission 85852

s.am._ · python · License unknown

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Vendorable · source mirrored · license unknownView source →

No package. Vendor the mirrored source: 451 lines, June 9 Researcher Reciprocity License v1.0.

finetuned_naive.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-nvfp4-gemv-85852?include=source"
interfacepython
Compatibility
measured onNVIDIA B200
declared hardwareNVIDIA B200
architecturessm_100
dtypesfp8_e4m3, nvfp4

Benchmark evidence

1 measurement across 1 GPU, fastest first.

Operation / workload
Hardware
Latency
Rank
Observed
NVFP4 GEMVsuite of 3 cases
NVIDIA B200
22.1µs
#36 of 678
2025-11-19

Reported · How evidence levels are derived →

Source and license

sourceavailable
revision digestsha256:0185e2ca04468d611f39ba5acd72f25ed21731bc5891a98e6b7dd5a6c98bc337
license declaredunknown
license concludedunknown
authorss.am._
imported2026-08-15

Techniques

Extracted from the mirrored source by pattern, never inferred. Each row cites its line.

fp4if (params.k <= 256) { // <= 512 FP4 values
fp8const __nv_fp8_e4m3* rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
shared-memory__shared__ float sdata[THREADS_PER_ROW];

Kernel source

finetuned_naive.py451 lines
import torch
from torch.utils.cpp_extension import load_inline
from task import input_t, output_t

# ---- C++ stub: declare the function so load_inline can bind it ----
gemv_cpp = r"""
#include <torch/extension.h>

// Forward declaration so PyTorch can bind it (definition is in the CUDA source).
torch::Tensor cuda_nvfp4_gemv(torch::Tensor A,
                            torch::Tensor B,
                            torch::Tensor C,
                            torch::Tensor SFA,
                            torch::Tensor SFB);
"""

# ---- CUDA source: struct, kernel, launcher, and Python-facing wrapper ----
gemv_cuda = r"""
#include <assert.h>
#include <cuda.h>
#include <stdio.h>
#include <cuda_runtime.h>

#include <torch/extension.h>
#include <ATen/cuda/CUDAContext.h>
#include <c10/cuda/CUDAGuard.h>

#include <cuda_fp4.h>
#include <cuda_bf16.h>
#include <cuda_fp8.h>

// ---- gemv.h ----
struct Gemv_params {
    using index_t = uint64_t;

    int b, m, k, real_k;

    void *__restrict__ a_ptr;
    void *__restrict__ b_ptr;
    void *__restrict__ sfa_ptr;
    void *__restrict__ sfb_ptr;
    void *__restrict__ o_ptr;

    index_t a_batch_stride;
    index_t b_batch_stride;
    index_t sfa_batch_stride;
    index_t sfb_batch_stride;
    index_t o_batch_stride;

    index_t a_row_stride;
    index_t b_row_stride;
    index_t sfa_row_stride;
    index_t sfb_row_stride;
    index_t o_row_stride;
};

static constexpr int BLOCK_SIZE = 128; // 128

__device__ __forceinline__ void load_block_16x2fp4(
    const __nv_fp4x2_e2m1* rowA,
    const __nv_fp4x2_e2m1* vecB,
    const uint16_t*        rowS_u16,
    const uint16_t*        vecS_u16,
    int                    elem_base,
    int                    block_base,
    uint64_t (&a_regs)[2],
    uint64_t (&b_regs)[2],
    uint16_t &sfa_regs,
    uint16_t &sfb_regs)
{
    uint64_t rowA_addr = reinterpret_cast<uint64_t>(rowA + elem_base);
    uint64_t vecB_addr = reinterpret_cast<uint64_t>(vecB + elem_base);
    uint64_t rowS_addr = reinterpret_cast<uint64_t>(rowS_u16 + block_base);
    uint64_t vecS_addr = reinterpret_cast<uint64_t>(vecS_u16 + block_base);

    asm volatile(
        "ld.global.u64.v2 {%0, %1}, [%4];\n\t"
        "ld.global.u64.v2 {%2, %3}, [%5];\n\t"
        : "=l"(a_regs[0]), "=l"(a_regs[1]),
          "=l"(b_regs[0]), "=l"(b_regs[1])
        : "l"(rowA_addr), "l"(vecB_addr)
    );

    asm volatile(
        "ld.global.u16 %0, [%2];\n\t"
        "ld.global.u16 %1, [%3];\n\t"
        : "=h"(sfa_regs), "=h"(sfb_regs)
        : "l"(rowS_addr), "l"(vecS_addr)
    );
}


__device__ __forceinline__ float block_scaled_fma_16x2fp4(
    const uint64_t (&a_regs)[2],
    const uint64_t (&b_regs)[2],
    uint16_t       sfa_regs,
    uint16_t       sfb_regs)
{
    uint32_t const* a_regs_packed = reinterpret_cast<uint32_t const*>(&a_regs);
    uint32_t const* b_regs_packed = reinterpret_cast<uint32_t const*>(&b_regs);

    float out_f32;

    asm volatile(
        "{\n"
        // 8 bytes of A and B at a time (reused for upper half)
        ".reg .b8 a0_0, a0_1, a0_2, a0_3;\n"
        ".reg .b8 a0_4, a0_5, a0_6, a0_7;\n"
        ".reg .b8 b0_0, b0_1, b0_2, b0_3;\n"
        ".reg .b8 b0_4, b0_5, b0_6, b0_7;\n"

        // scales and accumulators
        ".reg .f16x2 sfa_f16x2, sfb_f16x2, sf_f16x2;\n"
        ".reg .f16x2 scale0_f16x2, scale1_f16x2;\n"
        ".reg .f16x2 accum_total, accum_group;\n"

        // converted fp4 -> f16x2 (only 8 per vector kept live)
        ".reg .f16x2 cvt_0_0, cvt_0_1, cvt_0_2, cvt_0_3;\n"
        ".reg .f16x2 cvt_0_4, cvt_0_5, cvt_0_6, cvt_0_7;\n"
        ".reg .f16x2 cvt_1_0, cvt_1_1, cvt_1_2, cvt_1_3;\n"
        ".reg .f16x2 cvt_1_4, cvt_1_5, cvt_1_6, cvt_1_7;\n"

        ".reg .f16 lane0, lane1, result_f16;\n"
        ".reg .f32 result_f32;\n"

        // scales
        "cvt.rn.f16x2.e4m3x2 sfa_f16x2, %5;\n"
        "cvt.rn.f16x2.e4m3x2 sfb_f16x2, %6;\n"
        "mul.rn.f16x2 sf_f16x2, sfa_f16x2, sfb_f16x2;\n"
        "mov.b32 {lane0, lane1}, sf_f16x2;\n"
        "mov.b32 scale0_f16x2, {lane0, lane0};\n"
        "mov.b32 scale1_f16x2, {lane1, lane1};\n"

        "mov.b32 accum_total, 0;\n"

        //----------------------------------------------------------------------
        // First 8×(2×FP4) -> uses scale0
        //----------------------------------------------------------------------
        "mov.b32 {a0_0, a0_1, a0_2, a0_3}, %1;\n"
        "mov.b32 {a0_4, a0_5, a0_6, a0_7}, %2;\n"
        "mov.b32 {b0_0, b0_1, b0_2, b0_3}, %3;\n"
        "mov.b32 {b0_4, b0_5, b0_6, b0_7}, %4;\n"

        // all conversions first
        "cvt.rn.f16x2.e2m1x2 cvt_0_0, a0_0;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_0, b0_0;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_1, a0_1;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_1, b0_1;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_2, a0_2;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_2, b0_2;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_3, a0_3;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_3, b0_3;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_4, a0_4;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_4, b0_4;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_5, a0_5;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_5, b0_5;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_6, a0_6;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_6, b0_6;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_7, a0_7;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_7, b0_7;\n"

        // then all FMAs into one group accumulator
        "mov.b32 accum_group, 0;\n"
        "fma.rn.f16x2 accum_group, cvt_0_0, cvt_1_0, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_1, cvt_1_1, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_2, cvt_1_2, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_3, cvt_1_3, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_4, cvt_1_4, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_5, cvt_1_5, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_6, cvt_1_6, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_7, cvt_1_7, accum_group;\n"

        "mul.rn.f16x2 accum_group, scale0_f16x2, accum_group;\n"
        "add.rn.f16x2 accum_total, accum_total, accum_group;\n"

        //----------------------------------------------------------------------
        // Second 8×(2×FP4) -> uses scale1, reusing all the same regs
        //----------------------------------------------------------------------
        "mov.b32 {a0_0, a0_1, a0_2, a0_3}, %7;\n"
        "mov.b32 {a0_4, a0_5, a0_6, a0_7}, %8;\n"
        "mov.b32 {b0_0, b0_1, b0_2, b0_3}, %9;\n"
        "mov.b32 {b0_4, b0_5, b0_6, b0_7}, %10;\n"

        // conversions for upper half
        "cvt.rn.f16x2.e2m1x2 cvt_0_0, a0_0;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_0, b0_0;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_1, a0_1;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_1, b0_1;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_2, a0_2;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_2, b0_2;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_3, a0_3;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_3, b0_3;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_4, a0_4;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_4, b0_4;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_5, a0_5;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_5, b0_5;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_6, a0_6;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_6, b0_6;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_0_7, a0_7;\n"
        "cvt.rn.f16x2.e2m1x2 cvt_1_7, b0_7;\n"

        "mov.b32 accum_group, 0;\n"
        "fma.rn.f16x2 accum_group, cvt_0_0, cvt_1_0, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_1, cvt_1_1, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_2, cvt_1_2, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_3, cvt_1_3, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_4, cvt_1_4, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_5, cvt_1_5, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_6, cvt_1_6, accum_group;\n"
        "fma.rn.f16x2 accum_group, cvt_0_7, cvt_1_7, accum_group;\n"

        "mul.rn.f16x2 accum_group, scale1_f16x2, accum_group;\n"
        "add.rn.f16x2 accum_total, accum_total, accum_group;\n"

        // final reduction to scalar f16 -> then upconvert to f32
        "mov.b32 {lane0, lane1}, accum_total;\n"
        "add.rn.f16 result_f16, lane0, lane1;\n"
        "cvt.f32.f16 result_f32, result_f16;\n"
        "mov.b32 %0, result_f32;\n"

        "}\n"
        : "=f"(out_f32)
        : "r"(a_regs_packed[0]), "r"(a_regs_packed[1]),
          "r"(b_regs_packed[0]), "r"(b_regs_packed[1]),
          "h"(sfa_regs), "h"(sfb_regs),
          "r"(a_regs_packed[2]), "r"(a_regs_packed[3]),
          "r"(b_regs_packed[2]), "r"(b_regs_packed[3])
        : "memory"
    );

    return out_f32;
}

template <int ROWS_PER_BLOCK, int THREADS_PER_ROW>
__global__ void __launch_bounds__(ROWS_PER_BLOCK*THREADS_PER_ROW, 8)
gemv_kernel_shared(const __grid_constant__ Gemv_params params)
{
    const int tid   = threadIdx.x;
    const int rib   = tid / THREADS_PER_ROW;
    const int lane  = tid % THREADS_PER_ROW;
    const int batch = blockIdx.z;
    const int row   = blockIdx.x * ROWS_PER_BLOCK + rib;


    const size_t A_batch_base   = static_cast<size_t>(batch) * params.a_batch_stride;
    const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
    const size_t B_batch_base   = static_cast<size_t>(batch) * params.b_batch_stride;
    const size_t SFB_batch_base = static_cast<size_t>(batch) * params.sfb_batch_stride;
    const size_t C_batch_base   = static_cast<size_t>(batch) * params.o_batch_stride;


    const __nv_fp4x2_e2m1* rowA = static_cast<const __nv_fp4x2_e2m1*>(params.a_ptr) + A_batch_base   + row * params.a_row_stride;
    const __nv_fp8_e4m3*   rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
    const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
    const __nv_fp8_e4m3*   vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;


    const uint16_t* rowS_u16 = reinterpret_cast<const uint16_t*>(rowS);
    const uint16_t* vecS_u16 = reinterpret_cast<const uint16_t*>(vecS);


    float sum = 0.f;


    int iters = params.k / (THREADS_PER_ROW * 16);


    for (int idx = 0; idx < iters; ++idx) {
        int block_base = idx * THREADS_PER_ROW + lane;
        int elem_base  = block_base * 16;


        uint64_t a_regs[2], b_regs[2];
        uint16_t sfa_regs, sfb_regs;


        load_block_16x2fp4(
            rowA, vecB,
            rowS_u16, vecS_u16,
            elem_base, block_base,
            a_regs, b_regs,
            sfa_regs, sfb_regs);
        sum += block_scaled_fma_16x2fp4(a_regs, b_regs, sfa_regs, sfb_regs);;
    }


    __shared__ float sdata[THREADS_PER_ROW];
    sdata[lane] = sum;
    __syncthreads();


    if (tid < 64) sdata[lane] += sdata[lane+64];
    __syncthreads();


    if (lane < 32) {
        float val = sdata[lane] + sdata[lane + 32];
        val += __shfl_down_sync(0xffffffff, val, 16);
        val += __shfl_down_sync(0xffffffff, val, 8);
        val += __shfl_down_sync(0xffffffff, val, 4);
        val += __shfl_down_sync(0xffffffff, val, 2);
        val += __shfl_down_sync(0xffffffff, val, 1);
       
        if (lane == 0) {
            __half* out = (__half*)params.o_ptr + C_batch_base + row;
            out[0] = __float2half(val);
        }
    }
}

template <int ROWS_PER_BLOCK, int THREADS_PER_ROW>
__global__ void __launch_bounds__(ROWS_PER_BLOCK*THREADS_PER_ROW, 8)
gemv_kernel(const __grid_constant__ Gemv_params params)
{
    const int tid   = threadIdx.x;
    const int rib   = tid / THREADS_PER_ROW;
    const int lane  = tid % THREADS_PER_ROW;
    const int batch = blockIdx.z;
    const int row   = blockIdx.x * ROWS_PER_BLOCK + rib;

    const size_t A_batch_base   = static_cast<size_t>(batch) * params.a_batch_stride;
    const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
    const size_t B_batch_base   = static_cast<size_t>(batch) * params.b_batch_stride;
    const size_t SFB_batch_base = static_cast<size_t>(batch) * params.sfb_batch_stride;
    const size_t C_batch_base   = static_cast<size_t>(batch) * params.o_batch_stride;

    const __nv_fp4x2_e2m1* rowA = static_cast<const __nv_fp4x2_e2m1*>(params.a_ptr) + A_batch_base   + row * params.a_row_stride;
    const __nv_fp8_e4m3*   rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
    const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
    const __nv_fp8_e4m3*   vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;

    const uint16_t* rowS_u16 = reinterpret_cast<const uint16_t*>(rowS);
    const uint16_t* vecS_u16 = reinterpret_cast<const uint16_t*>(vecS);

    float sum = 0.f;

    int iters = params.k / (THREADS_PER_ROW * 16);

    for (int idx = 0; idx < iters; ++idx) {
        int block_base = idx * THREADS_PER_ROW + lane;
        int elem_base  = block_base * 16;

        uint64_t a_regs[2], b_regs[2];
        uint16_t sfa_regs, sfb_regs;

        load_block_16x2fp4(
            rowA, vecB,
            rowS_u16, vecS_u16,
            elem_base, block_base,
            a_regs, b_regs,
            sfa_regs, sfb_regs);
        sum += block_scaled_fma_16x2fp4(a_regs, b_regs, sfa_regs, sfb_regs);;
    }

    #pragma unroll
    for (int offset = THREADS_PER_ROW / 2; offset > 0; offset /= 2) {
        sum += __shfl_down_sync(0xffffffffu, sum, offset, THREADS_PER_ROW);
    }

    if (lane == 0) {
        __half* out = (__half*)params.o_ptr + C_batch_base + row;
        out[0] = __float2half(sum);
    }
}


torch::Tensor cuda_nvfp4_gemv(torch::Tensor A,
                            torch::Tensor B,
                            torch::Tensor C,
                            torch::Tensor SFA,
                            torch::Tensor SFB)
{

    const auto sizes = A.sizes();
    const int M = sizes[0];
    const int K = sizes[1];
    const int L = sizes[2];

    Gemv_params params{};
    params.b = L;
    params.m = M;
    params.k = K;

    params.a_ptr  = A.data_ptr();
    params.b_ptr  = B.data_ptr();
    params.sfa_ptr= SFA.data_ptr();
    params.sfb_ptr= SFB.data_ptr();
    params.o_ptr  = C.data_ptr();

    params.a_batch_stride  = A.stride(2);
    params.b_batch_stride  = B.stride(2);
    params.sfa_batch_stride= SFA.stride(2);
    params.sfb_batch_stride= SFB.stride(2);
    params.o_batch_stride  = C.stride(2);

    params.a_row_stride  = A.stride(0);
    params.b_row_stride  = B.stride(0);
    params.sfa_row_stride= SFA.stride(0);
    params.sfb_row_stride= SFB.stride(0);
    params.o_row_stride  = C.stride(0);

    auto stream = at::cuda::getCurrentCUDAStream().stream();
    if (params.k <= 256) {  // <= 512 FP4 values
        dim3 grid(params.m / 16, 1, params.b);
        dim3 block(128, 1, 1);
        gemv_kernel<16, 8><<<grid, block, 0, stream>>>(params);
    } else if (params.k == 3584) {
        dim3 block(32, 1, 1);
        dim3 grid(params.m / 4, 1, params.b);
        gemv_kernel<4, 8><<<grid, block, 0, stream>>>(params);
    } else if (params.k == 8192) {
        dim3 block(128, 1, 1);
        dim3 grid(params.m, 1, params.b);
        gemv_kernel_shared<1, 128><<<grid, block>>>(params);
    } else if (params.k == 1024) {
        dim3 block(64, 1, 1);
        dim3 grid(params.m / 8, 1, params.b);
        gemv_kernel<8, 8><<<grid, block, 0, stream>>>(params);
    } else {
        dim3 block(128, 1, 1);
        dim3 grid(params.m / 8, 1, params.b);
        gemv_kernel<8, 16><<<grid, block, 0, stream>>>(params);
    }

    return C;
}
"""

# ---- build the module ----
nvfp4_module = load_inline(
    name="nvfp4_gemv",
    cpp_sources=[gemv_cpp],
    cuda_sources=[gemv_cuda],
    functions=["cuda_nvfp4_gemv"],  # this exposes the function to Python
    extra_cuda_cflags=[
        "-std=c++17",
        "-gencode=arch=compute_100a,code=sm_100a",
        "--ptxas-options=--gpu-name=sm_100a",
        "-O3",
        "-w",
        "--use_fast_math",
        "-allow-unsupported-compiler",
    ],
    extra_ldflags=["-lcuda", "-lcublas"],
    verbose=True,
)


def custom_kernel(data: input_t) -> output_t:
    return nvfp4_module.cuda_nvfp4_gemv(data[0], data[1], data[6], data[2], data[3])
scrolls · 451 lines total

Source code from GPU Mode and the KernelBot dataset · June 9 Researcher Reciprocity License v1.0

Changes from previous submission

Against this author's previous submission submission 80484.

⋯ 5 unchanged lines
gemv_cpp = r"""
#include <torch/extension.h>
- // Single Python-visible entry point that dispatches between kernels
- torch::Tensor nvfp4_gemv_dispatch(torch::Tensor A,
- torch::Tensor B,
- torch::Tensor C,
- torch::Tensor SFA,
- torch::Tensor SFB);
+ // Forward declaration so PyTorch can bind it (definition is in the CUDA source).
+ torch::Tensor cuda_nvfp4_gemv(torch::Tensor A,
+ torch::Tensor B,
+ torch::Tensor C,
+ torch::Tensor SFA,
+ torch::Tensor SFB);
"""
- # ---- CUDA source: params struct, both kernels, launchers, and Python-facing wrapper ----
+ # ---- CUDA source: struct, kernel, launcher, and Python-facing wrapper ----
gemv_cuda = r"""
#include <assert.h>
#include <cuda.h>
⋯ 8 unchanged lines
#include <cuda_bf16.h>
#include <cuda_fp8.h>
- // ---- gemv.h-ish: params struct ----
+ // ---- gemv.h ----
struct Gemv_params {
using index_t = uint64_t;
⋯ 18 unchanged lines
index_t o_row_stride;
};
- static constexpr int ROWS_PER_BLOCK = 8;
- static constexpr int THREADS_PER_ROW = 16;
- static constexpr int BLOCK_SIZE = ROWS_PER_BLOCK * THREADS_PER_ROW; // 128
- static constexpr int BUFFER = 2;
- static constexpr int STAGES = 4;
+ static constexpr int BLOCK_SIZE = 128; // 128
- template <int LoadBytes>
- __device__ __forceinline__ void cp_async_ca(uint32_t smem_addr, void const *global_ptr, bool pred_guard=true) {
- asm volatile(
- "{\n"
- " .reg .pred p;\n"
- " setp.ne.b32 p, %0, 0;\n"
- " @p cp.async.ca.shared.global.L2::128B [%1], [%2], %3;\n"
- "}\n"
- :
- :"r"((int)pred_guard), "r"(smem_addr), "l"(global_ptr), "n"(LoadBytes)
- );
- }
-
- struct SharedStorage {
- alignas(128) __nv_fp4x2_e2m1 A[BUFFER][STAGES][128 * 16];
- alignas(128) __nv_fp4x2_e2m1 B[BUFFER][STAGES][THREADS_PER_ROW * 16];
- alignas(128) __nv_fp8_e4m3 SFA[BUFFER][STAGES][128 * 2];
- alignas(128) __nv_fp8_e4m3 SFB[BUFFER][STAGES][THREADS_PER_ROW * 2];
- };
-
-
- __device__ __forceinline__ void cpasync_load(
- int buffer_idx,
- int &global_k, // should be in 2xfp4
- int smem_offset_A,
- int smem_offset_B,
- int smem_sf_write_offset,
- int lane,
- bool is_even,
- bool load_b,
- bool valid,
- const __nv_fp4x2_e2m1* rowA,
- const __nv_fp4x2_e2m1* vecB,
- const __nv_fp8_e4m3* rowS,
- const __nv_fp8_e4m3* vecS,
- SharedStorage& smem)
- {
- for (int s = 0; s < STAGES; ++s) {
- int SF_offset = (global_k >> 3) + lane * 2;
-
- uint32_t smem_addr_A = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.A[buffer_idx][s][smem_offset_A]));
- uint32_t smem_addr_B = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.B[buffer_idx][s][smem_offset_B]));
- uint32_t smem_addr_SFA = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.SFA[buffer_idx][s][smem_sf_write_offset]));
- uint32_t smem_addr_SFB = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.SFB[buffer_idx][s][(lane / 2) * 4]));
-
- cp_async_ca<16>(smem_addr_A, rowA + global_k, valid);
- cp_async_ca<16>(smem_addr_B, vecB + global_k, valid && load_b);
- cp_async_ca<4>(smem_addr_SFA, rowS + SF_offset, valid && is_even);
- cp_async_ca<4>(smem_addr_SFB, vecS + SF_offset, valid && is_even && load_b);
-
- global_k += 256;
- }
- }
-
__device__ __forceinline__ void load_block_16x2fp4(
const __nv_fp4x2_e2m1* rowA,
const __nv_fp4x2_e2m1* vecB,
⋯ 27 unchanged lines
);
}
- __device__ __forceinline__ void load_fragments(
- uint64_t (&a_regs)[2],
- uint64_t (&b_regs)[2],
- uint16_t &sfa_regs,
- uint16_t &sfb_regs,
- int lane,
- int smem_pipe_read,
- int k_block,
- int smem_offset_A,
- int smem_offset_B,
- int smem_sf_offset,
- SharedStorage& smem)
- {
- uint32_t smem_addr_a = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.A[smem_pipe_read][k_block][smem_offset_A]));
- uint32_t smem_addr_b = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.B[smem_pipe_read][k_block][smem_offset_B]));
-
- asm volatile(
- "ld.shared.v2.u64 {%0, %1}, [%4];\n\t"
- "ld.shared.v2.u64 {%2, %3}, [%5];\n\t"
- : "=l"(a_regs[0]), "=l"(a_regs[1]),
- "=l"(b_regs[0]), "=l"(b_regs[1])
- : "r"(smem_addr_a), "r"(smem_addr_b)
- );
- uint32_t smem_addr_sfa = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.SFA[smem_pipe_read][k_block][smem_sf_offset]));
- uint32_t smem_addr_sfb = static_cast<uint32_t>(__cvta_generic_to_shared(&smem.SFB[smem_pipe_read][k_block][lane * 2]));
-
- asm volatile(
- "ld.shared.u16 %0, [%2];\n\t"
- "ld.shared.u16 %1, [%3];\n\t"
- : "=h"(sfa_regs), "=h"(sfb_regs)
- : "r"(smem_addr_sfa), "r"(smem_addr_sfb)
- );
- }
-
-
-
- __device__ __forceinline__ __half block_scaled_fma_16x2fp4(
+ __device__ __forceinline__ float block_scaled_fma_16x2fp4(
const uint64_t (&a_regs)[2],
const uint64_t (&b_regs)[2],
uint16_t sfa_regs,
⋯ 2 unchanged lines
uint32_t const* a_regs_packed = reinterpret_cast<uint32_t const*>(&a_regs);
uint32_t const* b_regs_packed = reinterpret_cast<uint32_t const*>(&b_regs);
- uint16_t out_half_bits;
+ float out_f32;
asm volatile(
"{\n"
- ".reg .b8 byte0_0, byte0_1, byte0_2, byte0_3;\n"
- ".reg .b8 byte0_4, byte0_5, byte0_6, byte0_7;\n"
- ".reg .b8 byte0_8, byte0_9, byte0_10, byte0_11;\n"
- ".reg .b8 byte0_12, byte0_13, byte0_14, byte0_15;\n"
- ".reg .b8 byte1_0, byte1_1, byte1_2, byte1_3;\n"
- ".reg .b8 byte1_4, byte1_5, byte1_6, byte1_7;\n"
- ".reg .b8 byte1_8, byte1_9, byte1_10, byte1_11;\n"
- ".reg .b8 byte1_12, byte1_13, byte1_14, byte1_15;\n"
+ // 8 bytes of A and B at a time (reused for upper half)
+ ".reg .b8 a0_0, a0_1, a0_2, a0_3;\n"
+ ".reg .b8 a0_4, a0_5, a0_6, a0_7;\n"
+ ".reg .b8 b0_0, b0_1, b0_2, b0_3;\n"
+ ".reg .b8 b0_4, b0_5, b0_6, b0_7;\n"
- ".reg .f16x2 accum_0, accum_1, accum_2, accum_3;\n"
- ".reg .f16x2 accum_4, accum_5, accum_6, accum_7;\n"
- ".reg .f16x2 accum_8, accum_9, accum_10, accum_11;\n"
- ".reg .f16x2 accum_12, accum_13, accum_14, accum_15;\n"
+ // scales and accumulators
+ ".reg .f16x2 sfa_f16x2, sfb_f16x2, sf_f16x2;\n"
+ ".reg .f16x2 scale0_f16x2, scale1_f16x2;\n"
+ ".reg .f16x2 accum_total, accum_group;\n"
- ".reg .f16x2 sfa_f16x2;\n"
- ".reg .f16x2 sfb_f16x2;\n"
- ".reg .f16x2 sf_f16x2;\n"
-
+ // converted fp4 -> f16x2 (only 8 per vector kept live)
".reg .f16x2 cvt_0_0, cvt_0_1, cvt_0_2, cvt_0_3;\n"
".reg .f16x2 cvt_0_4, cvt_0_5, cvt_0_6, cvt_0_7;\n"
- ".reg .f16x2 cvt_0_8, cvt_0_9, cvt_0_10, cvt_0_11;\n"
- ".reg .f16x2 cvt_0_12, cvt_0_13, cvt_0_14, cvt_0_15;\n"
".reg .f16x2 cvt_1_0, cvt_1_1, cvt_1_2, cvt_1_3;\n"
".reg .f16x2 cvt_1_4, cvt_1_5, cvt_1_6, cvt_1_7;\n"
- ".reg .f16x2 cvt_1_8, cvt_1_9, cvt_1_10, cvt_1_11;\n"
- ".reg .f16x2 cvt_1_12, cvt_1_13, cvt_1_14, cvt_1_15;\n"
- ".reg .f16 result_f16, lane0, lane1;\n"
- ".reg .f16x2 mul_f16x2_0, mul_f16x2_1;\n"
- "cvt.rn.f16x2.e4m3x2 sfa_f16x2, %9;\n"
- "cvt.rn.f16x2.e4m3x2 sfb_f16x2, %10;\n"
+ ".reg .f16 lane0, lane1, result_f16;\n"
+ ".reg .f32 result_f32;\n"
- "mov.b32 accum_0, 0;\n"
- "mov.b32 accum_1, 0;\n"
- "mov.b32 accum_2, 0;\n"
- "mov.b32 accum_3, 0;\n"
- "mov.b32 accum_4, 0;\n"
- "mov.b32 accum_5, 0;\n"
- "mov.b32 accum_6, 0;\n"
- "mov.b32 accum_7, 0;\n"
- "mov.b32 accum_8, 0;\n"
- "mov.b32 accum_9, 0;\n"
- "mov.b32 accum_10, 0;\n"
- "mov.b32 accum_11, 0;\n"
- "mov.b32 accum_12, 0;\n"
- "mov.b32 accum_13, 0;\n"
- "mov.b32 accum_14, 0;\n"
- "mov.b32 accum_15, 0;\n"
-
+ // scales
+ "cvt.rn.f16x2.e4m3x2 sfa_f16x2, %5;\n"
+ "cvt.rn.f16x2.e4m3x2 sfb_f16x2, %6;\n"
"mul.rn.f16x2 sf_f16x2, sfa_f16x2, sfb_f16x2;\n"
"mov.b32 {lane0, lane1}, sf_f16x2;\n"
- "mov.b32 mul_f16x2_0, {lane0, lane0};\n"
- "mov.b32 mul_f16x2_1, {lane1, lane1};\n"
+ "mov.b32 scale0_f16x2, {lane0, lane0};\n"
+ "mov.b32 scale1_f16x2, {lane1, lane1};\n"
- "mov.b32 {byte0_0, byte0_1, byte0_2, byte0_3}, %1;\n"
- "mov.b32 {byte0_4, byte0_5, byte0_6, byte0_7}, %2;\n"
- "mov.b32 {byte0_8, byte0_9, byte0_10, byte0_11}, %3;\n"
- "mov.b32 {byte0_12, byte0_13, byte0_14, byte0_15}, %4;\n"
- "mov.b32 {byte1_0, byte1_1, byte1_2, byte1_3}, %5;\n"
- "mov.b32 {byte1_4, byte1_5, byte1_6, byte1_7}, %6;\n"
- "mov.b32 {byte1_8, byte1_9, byte1_10, byte1_11}, %7;\n"
- "mov.b32 {byte1_12, byte1_13, byte1_14, byte1_15}, %8;\n"
+ "mov.b32 accum_total, 0;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_0, byte0_0;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_1, byte0_1;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_2, byte0_2;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_3, byte0_3;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_4, byte0_4;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_5, byte0_5;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_6, byte0_6;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_7, byte0_7;\n"
+ //----------------------------------------------------------------------
+ // First 8×(2×FP4) -> uses scale0
+ //----------------------------------------------------------------------
+ "mov.b32 {a0_0, a0_1, a0_2, a0_3}, %1;\n"
+ "mov.b32 {a0_4, a0_5, a0_6, a0_7}, %2;\n"
+ "mov.b32 {b0_0, b0_1, b0_2, b0_3}, %3;\n"
+ "mov.b32 {b0_4, b0_5, b0_6, b0_7}, %4;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_8, byte0_8;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_9, byte0_9;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_10, byte0_10;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_11, byte0_11;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_12, byte0_12;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_13, byte0_13;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_14, byte0_14;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_0_15, byte0_15;\n"
+ // all conversions first
+ "cvt.rn.f16x2.e2m1x2 cvt_0_0, a0_0;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_0, b0_0;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_1, a0_1;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_1, b0_1;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_2, a0_2;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_2, b0_2;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_3, a0_3;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_3, b0_3;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_4, a0_4;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_4, b0_4;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_5, a0_5;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_5, b0_5;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_6, a0_6;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_6, b0_6;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_7, a0_7;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_7, b0_7;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_0, byte1_0;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_1, byte1_1;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_2, byte1_2;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_3, byte1_3;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_4, byte1_4;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_5, byte1_5;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_6, byte1_6;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_7, byte1_7;\n"
+ // then all FMAs into one group accumulator
+ "mov.b32 accum_group, 0;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_0, cvt_1_0, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_1, cvt_1_1, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_2, cvt_1_2, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_3, cvt_1_3, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_4, cvt_1_4, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_5, cvt_1_5, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_6, cvt_1_6, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_7, cvt_1_7, accum_group;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_8, byte1_8;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_9, byte1_9;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_10, byte1_10;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_11, byte1_11;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_12, byte1_12;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_13, byte1_13;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_14, byte1_14;\n"
- "cvt.rn.f16x2.e2m1x2 cvt_1_15, byte1_15;\n"
+ "mul.rn.f16x2 accum_group, scale0_f16x2, accum_group;\n"
+ "add.rn.f16x2 accum_total, accum_total, accum_group;\n"
- "fma.rn.f16x2 accum_0, cvt_0_0, cvt_1_0, accum_0;\n"
- "fma.rn.f16x2 accum_1, cvt_0_1, cvt_1_1, accum_1;\n"
- "fma.rn.f16x2 accum_2, cvt_0_2, cvt_1_2, accum_2;\n"
- "fma.rn.f16x2 accum_3, cvt_0_3, cvt_1_3, accum_3;\n"
- "fma.rn.f16x2 accum_4, cvt_0_4, cvt_1_4, accum_4;\n"
- "fma.rn.f16x2 accum_5, cvt_0_5, cvt_1_5, accum_5;\n"
- "fma.rn.f16x2 accum_6, cvt_0_6, cvt_1_6, accum_6;\n"
- "fma.rn.f16x2 accum_7, cvt_0_7, cvt_1_7, accum_7;\n"
+ //----------------------------------------------------------------------
+ // Second 8×(2×FP4) -> uses scale1, reusing all the same regs
+ //----------------------------------------------------------------------
+ "mov.b32 {a0_0, a0_1, a0_2, a0_3}, %7;\n"
+ "mov.b32 {a0_4, a0_5, a0_6, a0_7}, %8;\n"
+ "mov.b32 {b0_0, b0_1, b0_2, b0_3}, %9;\n"
+ "mov.b32 {b0_4, b0_5, b0_6, b0_7}, %10;\n"
- "fma.rn.f16x2 accum_8, cvt_0_8, cvt_1_8, accum_8;\n"
- "fma.rn.f16x2 accum_9, cvt_0_9, cvt_1_9, accum_9;\n"
- "fma.rn.f16x2 accum_10, cvt_0_10, cvt_1_10, accum_10;\n"
- "fma.rn.f16x2 accum_11, cvt_0_11, cvt_1_11, accum_11;\n"
- "fma.rn.f16x2 accum_12, cvt_0_12, cvt_1_12, accum_12;\n"
- "fma.rn.f16x2 accum_13, cvt_0_13, cvt_1_13, accum_13;\n"
- "fma.rn.f16x2 accum_14, cvt_0_14, cvt_1_14, accum_14;\n"
- "fma.rn.f16x2 accum_15, cvt_0_15, cvt_1_15, accum_15;\n"
+ // conversions for upper half
+ "cvt.rn.f16x2.e2m1x2 cvt_0_0, a0_0;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_0, b0_0;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_1, a0_1;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_1, b0_1;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_2, a0_2;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_2, b0_2;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_3, a0_3;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_3, b0_3;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_4, a0_4;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_4, b0_4;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_5, a0_5;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_5, b0_5;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_6, a0_6;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_6, b0_6;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_0_7, a0_7;\n"
+ "cvt.rn.f16x2.e2m1x2 cvt_1_7, b0_7;\n"
- "add.rn.f16x2 accum_0, accum_0, accum_1;\n"
- "add.rn.f16x2 accum_2, accum_2, accum_3;\n"
- "add.rn.f16x2 accum_4, accum_4, accum_5;\n"
- "add.rn.f16x2 accum_6, accum_6, accum_7;\n"
- "add.rn.f16x2 accum_8, accum_8, accum_9;\n"
- "add.rn.f16x2 accum_10, accum_10, accum_11;\n"
- "add.rn.f16x2 accum_12, accum_12, accum_13;\n"
- "add.rn.f16x2 accum_14, accum_14, accum_15;\n"
+ "mov.b32 accum_group, 0;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_0, cvt_1_0, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_1, cvt_1_1, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_2, cvt_1_2, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_3, cvt_1_3, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_4, cvt_1_4, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_5, cvt_1_5, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_6, cvt_1_6, accum_group;\n"
+ "fma.rn.f16x2 accum_group, cvt_0_7, cvt_1_7, accum_group;\n"
- "add.rn.f16x2 accum_0, accum_0, accum_2;\n"
- "add.rn.f16x2 accum_4, accum_4, accum_6;\n"
- "add.rn.f16x2 accum_8, accum_8, accum_10;\n"
- "add.rn.f16x2 accum_12, accum_12, accum_14;\n"
+ "mul.rn.f16x2 accum_group, scale1_f16x2, accum_group;\n"
+ "add.rn.f16x2 accum_total, accum_total, accum_group;\n"
- "add.rn.f16x2 accum_0, accum_0, accum_4;\n"
- "add.rn.f16x2 accum_8, accum_8, accum_12;\n"
-
- "mul.rn.f16x2 accum_0, mul_f16x2_0, accum_0;\n"
- "mul.rn.f16x2 accum_8, mul_f16x2_1, accum_8;\n"
-
- "add.rn.f16x2 accum_0, accum_0, accum_8;\n"
-
- "mov.b32 {lane0, lane1}, accum_0;\n"
+ // final reduction to scalar f16 -> then upconvert to f32
+ "mov.b32 {lane0, lane1}, accum_total;\n"
"add.rn.f16 result_f16, lane0, lane1;\n"
+ "cvt.f32.f16 result_f32, result_f16;\n"
+ "mov.b32 %0, result_f32;\n"
- "mov.b16 %0, result_f16;\n"
"}\n"
- : "=h"(out_half_bits)
+ : "=f"(out_f32)
: "r"(a_regs_packed[0]), "r"(a_regs_packed[1]),
- "r"(a_regs_packed[2]), "r"(a_regs_packed[3]),
"r"(b_regs_packed[0]), "r"(b_regs_packed[1]),
- "r"(b_regs_packed[2]), "r"(b_regs_packed[3]),
- "h"(sfa_regs), "h"(sfb_regs)
+ "h"(sfa_regs), "h"(sfb_regs),
+ "r"(a_regs_packed[2]), "r"(a_regs_packed[3]),
+ "r"(b_regs_packed[2]), "r"(b_regs_packed[3])
: "memory"
);
- union { uint16_t u; __half h; } conv;
- conv.u = out_half_bits;
- return conv.h;
+ return out_f32;
}
-
- __global__ void __launch_bounds__(BLOCK_SIZE, 8)
- gemv_kernel_fast(const __grid_constant__ Gemv_params params)
+ template <int ROWS_PER_BLOCK, int THREADS_PER_ROW>
+ __global__ void __launch_bounds__(ROWS_PER_BLOCK*THREADS_PER_ROW, 8)
+ gemv_kernel_shared(const __grid_constant__ Gemv_params params)
{
const int tid = threadIdx.x;
const int rib = tid / THREADS_PER_ROW;
⋯ 1 unchanged lines
const int batch = blockIdx.z;
const int row = blockIdx.x * ROWS_PER_BLOCK + rib;
- extern __shared__ __align__(128) uint8_t shared_storage[];
- SharedStorage &smem = *reinterpret_cast<SharedStorage*>(shared_storage);
const size_t A_batch_base = static_cast<size_t>(batch) * params.a_batch_stride;
const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
⋯ 1 unchanged lines
const size_t SFB_batch_base = static_cast<size_t>(batch) * params.sfb_batch_stride;
const size_t C_batch_base = static_cast<size_t>(batch) * params.o_batch_stride;
+
const __nv_fp4x2_e2m1* rowA = static_cast<const __nv_fp4x2_e2m1*>(params.a_ptr) + A_batch_base + row * params.a_row_stride;
const __nv_fp8_e4m3* rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
const __nv_fp8_e4m3* vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;
- rowA += lane * 16;
- vecB += lane * 16;
- const int k = params.k;
+ const uint16_t* rowS_u16 = reinterpret_cast<const uint16_t*>(rowS);
+ const uint16_t* vecS_u16 = reinterpret_cast<const uint16_t*>(vecS);
+
float sum = 0.f;
- int global_k = 0;
- const int smem_offset_A = tid * 16;
- const int smem_offset_B = lane * 16;
- const int smem_sf_write_offset = (tid / 2) * 4;
- const int smem_sf_offset = tid * 2;
- const bool load_b = rib == 0;
- const bool is_even = (lane % 2 == 0);
- // prefetch to buffer 0
- cpasync_load(
- 0,
- global_k,
- smem_offset_A,
- smem_offset_B,
- smem_sf_write_offset,
- lane,
- is_even,
- load_b,
- true,
- rowA,
- vecB,
- rowS,
- vecS,
- smem
- );
- asm volatile("cp.async.commit_group;\n" ::);
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
- uint64_t a_regs[2][2], b_regs[2][2];
- uint16_t sfa_regs[2], sfb_regs[2];
-
- int smem_pipe_read = 0;
- int smem_pipe_write = 1;
-
- // prefetch buffer 0 stage 0 to registers 0
- load_fragments(
- a_regs[0],
- b_regs[0],
- sfa_regs[0],
- sfb_regs[0],
- lane,
- 0, //smem_pipe_read
- 0, //k_block
- smem_offset_A,
- smem_offset_B,
- smem_sf_offset,
- smem
- );
- asm volatile("cp.async.commit_group;\n" ::);
-
int iters = params.k / (THREADS_PER_ROW * 16);
- int idx = 0;
- while (idx < iters) {
- int smem_pipe_read_curr = smem_pipe_read;
- for (int k_block = 0; k_block < STAGES; ++k_block)
- {
- if (k_block == STAGES-1)
- {
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
+ for (int idx = 0; idx < iters; ++idx) {
+ int block_base = idx * THREADS_PER_ROW + lane;
+ int elem_base = block_base * 16;
- smem_pipe_read_curr = smem_pipe_read;
- }
- auto k_block_next = (k_block + 1) % STAGES;
- int frag_idx_next = (k_block + 1) & 1;
+ uint64_t a_regs[2], b_regs[2];
+ uint16_t sfa_regs, sfb_regs;
- load_fragments(
- a_regs[frag_idx_next],
- b_regs[frag_idx_next],
- sfa_regs[frag_idx_next],
- sfb_regs[frag_idx_next],
- lane,
- smem_pipe_read_curr, //smem_pipe_read
- k_block_next, //k_block
- smem_offset_A,
- smem_offset_B,
- smem_sf_offset,
- smem
- );
- if (k_block == 0)
- {
- bool valid = (global_k < k);
- cpasync_load(
- smem_pipe_write,
- global_k,
- smem_offset_A,
- smem_offset_B,
- smem_sf_write_offset,
- lane,
- is_even,
- load_b,
- valid,
- rowA,
- vecB,
- rowS,
- vecS,
- smem);
- asm volatile("cp.async.commit_group;\n" ::);
-
- smem_pipe_write = smem_pipe_read;
- smem_pipe_read = (smem_pipe_read + 1) & 1;
- }
-
-
- int frag_idx = k_block & 1;
- __half h = block_scaled_fma_16x2fp4(
- a_regs[frag_idx],
- b_regs[frag_idx],
- sfa_regs[frag_idx],
- sfb_regs[frag_idx]);
- sum += __half2float(h);
-
- }
- idx += STAGES;
+ load_block_16x2fp4(
+ rowA, vecB,
+ rowS_u16, vecS_u16,
+ elem_base, block_base,
+ a_regs, b_regs,
+ sfa_regs, sfb_regs);
+ sum += block_scaled_fma_16x2fp4(a_regs, b_regs, sfa_regs, sfb_regs);;
}
- asm volatile("cp.async.wait_all;\n" ::);
+
+ __shared__ float sdata[THREADS_PER_ROW];
+ sdata[lane] = sum;
__syncthreads();
- unsigned mask = 0xffffffffu;
- sum += __shfl_down_sync(mask, sum, 8, 16);
- sum += __shfl_down_sync(mask, sum, 4, 16);
- sum += __shfl_down_sync(mask, sum, 2, 16);
- sum += __shfl_down_sync(mask, sum, 1, 16);
+ if (tid < 64) sdata[lane] += sdata[lane+64];
+ __syncthreads();
- if (lane == 0) {
- __half* out = (__half*)params.o_ptr + C_batch_base + row;
- out[0] = __float2half(sum);
- }
- }
- static inline void launch_kernel_fast(Gemv_params &params, cudaStream_t stream)
- {
- const int grid_x = (params.m + ROWS_PER_BLOCK - 1) / ROWS_PER_BLOCK;
- size_t smem_size = sizeof(SharedStorage);
- dim3 grid(grid_x, 1, params.b);
- dim3 block(BLOCK_SIZE, 1, 1);
- gemv_kernel_fast<<<grid, block, smem_size>>>(params);
- }
-
- __global__ void __launch_bounds__(BLOCK_SIZE, 8)
- gemv_kernel_k1024(const __grid_constant__ Gemv_params params)
- {
- const int tid = threadIdx.x;
- const int rib = tid / THREADS_PER_ROW;
- const int lane = tid % THREADS_PER_ROW;
- const int batch = blockIdx.z;
- const int row = blockIdx.x * ROWS_PER_BLOCK + rib;
-
- const size_t A_batch_base = static_cast<size_t>(batch) * params.a_batch_stride;
- const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
- const size_t B_batch_base = static_cast<size_t>(batch) * params.b_batch_stride;
- const size_t SFB_batch_base = static_cast<size_t>(batch) * params.sfb_batch_stride;
- const size_t C_batch_base = static_cast<size_t>(batch) * params.o_batch_stride;
-
- const __nv_fp4x2_e2m1* rowA = static_cast<const __nv_fp4x2_e2m1*>(params.a_ptr) + A_batch_base + row * params.a_row_stride;
- const __nv_fp8_e4m3* rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
- const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
- const __nv_fp8_e4m3* vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;
-
- const uint16_t* rowS_u16 = reinterpret_cast<const uint16_t*>(rowS);
- const uint16_t* vecS_u16 = reinterpret_cast<const uint16_t*>(vecS);
-
- float sum0 = 0.f;
- float sum1 = 0.f;
-
- // we know iters == 4, so two iterations here;
- // then force unroll to get all 4 “stages” laid out
- #pragma unroll
- for (int idx = 0; idx < 4; idx += 2) {
- // Stage idx
- {
- int block_base = (idx + 0) * THREADS_PER_ROW + lane;
- int elem_base = block_base * 16;
-
- uint64_t a_regs0[2], b_regs0[2];
- uint16_t sfa_regs0, sfb_regs0;
-
- load_block_16x2fp4(
- rowA, vecB,
- rowS_u16, vecS_u16,
- elem_base, block_base,
- a_regs0, b_regs0,
- sfa_regs0, sfb_regs0);
-
- __half h0 = block_scaled_fma_16x2fp4(a_regs0, b_regs0, sfa_regs0, sfb_regs0);
- sum0 += __half2float(h0);
+ if (lane < 32) {
+ float val = sdata[lane] + sdata[lane + 32];
+ val += __shfl_down_sync(0xffffffff, val, 16);
+ val += __shfl_down_sync(0xffffffff, val, 8);
+ val += __shfl_down_sync(0xffffffff, val, 4);
+ val += __shfl_down_sync(0xffffffff, val, 2);
+ val += __shfl_down_sync(0xffffffff, val, 1);
+
+ if (lane == 0) {
+ __half* out = (__half*)params.o_ptr + C_batch_base + row;
+ out[0] = __float2half(val);
}
-
- // Stage idx + 1
- {
- int block_base = (idx + 1) * THREADS_PER_ROW + lane;
- int elem_base = block_base * 16;
-
- uint64_t a_regs1[2], b_regs1[2];
- uint16_t sfa_regs1, sfb_regs1;
-
- load_block_16x2fp4(
- rowA, vecB,
- rowS_u16, vecS_u16,
- elem_base, block_base,
- a_regs1, b_regs1,
- sfa_regs1, sfb_regs1);
-
- __half h1 = block_scaled_fma_16x2fp4(a_regs1, b_regs1, sfa_regs1, sfb_regs1);
- sum1 += __half2float(h1);
- }
}
-
- float sum = sum0 + sum1;
-
-
-
- unsigned mask = 0xffffffffu;
- sum += __shfl_down_sync(mask, sum, 8, 16);
- sum += __shfl_down_sync(mask, sum, 4, 16);
- sum += __shfl_down_sync(mask, sum, 2, 16);
- sum += __shfl_down_sync(mask, sum, 1, 16);
-
- if (lane == 0) {
- __half* out = (__half*)params.o_ptr + C_batch_base + row;
- out[0] = __float2half(sum);
- }
}
- static inline void launch_kernel_k1024(Gemv_params &params, cudaStream_t stream)
+ template <int ROWS_PER_BLOCK, int THREADS_PER_ROW>
+ __global__ void __launch_bounds__(ROWS_PER_BLOCK*THREADS_PER_ROW, 8)
+ gemv_kernel(const __grid_constant__ Gemv_params params)
{
- const int grid_x = (params.m + ROWS_PER_BLOCK - 1) / ROWS_PER_BLOCK;
- size_t smem_size = sizeof(SharedStorage);
- dim3 grid(grid_x, 1, params.b);
- dim3 block(BLOCK_SIZE, 1, 1);
- gemv_kernel_k1024<<<grid, block, 0, stream>>>(params);
- }
-
- // ============================================================================
- // K=3584-specialized kernel
- // ============================================================================
-
- __global__ void __launch_bounds__(BLOCK_SIZE, 8)
- gemv_kernel_k3584(const __grid_constant__ Gemv_params params)
- {
const int tid = threadIdx.x;
const int rib = tid / THREADS_PER_ROW;
const int lane = tid % THREADS_PER_ROW;
const int batch = blockIdx.z;
const int row = blockIdx.x * ROWS_PER_BLOCK + rib;
- extern __shared__ __align__(128) uint8_t shared_storage[];
- SharedStorage &smem = *reinterpret_cast<SharedStorage*>(shared_storage);
-
const size_t A_batch_base = static_cast<size_t>(batch) * params.a_batch_stride;
const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
const size_t B_batch_base = static_cast<size_t>(batch) * params.b_batch_stride;
⋯ 5 unchanged lines
const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
const __nv_fp8_e4m3* vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;
- rowA += lane * 16;
- vecB += lane * 16;
+ const uint16_t* rowS_u16 = reinterpret_cast<const uint16_t*>(rowS);
+ const uint16_t* vecS_u16 = reinterpret_cast<const uint16_t*>(vecS);
- const int k = params.k;
-
float sum = 0.f;
- int global_k = 0;
- const int smem_offset_A = tid * 16;
- const int smem_offset_B = lane * 16;
- const int smem_sf_write_offset = (tid / 2) * 4;
- const int smem_sf_offset = tid * 2;
- const bool load_b = rib == 0;
- const bool is_even = (lane % 2 == 0);
- // prefetch to buffer 0
- cpasync_load(
- 0,
- global_k,
- smem_offset_A,
- smem_offset_B,
- smem_sf_write_offset,
- lane,
- is_even,
- load_b,
- true,
- rowA,
- vecB,
- rowS,
- vecS,
- smem
- );
- asm volatile("cp.async.commit_group;\n" ::);
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
+ int iters = params.k / (THREADS_PER_ROW * 16);
- uint64_t a_regs[2][2], b_regs[2][2];
- uint16_t sfa_regs[2], sfb_regs[2];
+ for (int idx = 0; idx < iters; ++idx) {
+ int block_base = idx * THREADS_PER_ROW + lane;
+ int elem_base = block_base * 16;
- int smem_pipe_read = 0;
- int smem_pipe_write = 1;
+ uint64_t a_regs[2], b_regs[2];
+ uint16_t sfa_regs, sfb_regs;
- // prefetch buffer 0 stage 0 to registers 0
- load_fragments(
- a_regs[0],
- b_regs[0],
- sfa_regs[0],
- sfb_regs[0],
- lane,
- 0, //smem_pipe_read
- 0, //k_block
- smem_offset_A,
- smem_offset_B,
- smem_sf_offset,
- smem
- );
- asm volatile("cp.async.commit_group;\n" ::);
-
- int total_stages = params.k / (THREADS_PER_ROW * 16);
- int full_iters = total_stages / STAGES; // Number of complete STAGES-groups
- int tail_stages = total_stages % STAGES; // Remaining stages
-
- // Main loop: process complete groups of STAGES
- for (int idx = 0; idx < full_iters; ++idx) {
- int smem_pipe_read_curr = smem_pipe_read;
-
- for (int k_block = 0; k_block < STAGES; ++k_block)
- {
- if (k_block == STAGES-1)
- {
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
-
- smem_pipe_read_curr = smem_pipe_read;
- }
-
- auto k_block_next = (k_block + 1) % STAGES;
- int frag_idx_next = (k_block + 1) & 1;
-
- load_fragments(
- a_regs[frag_idx_next],
- b_regs[frag_idx_next],
- sfa_regs[frag_idx_next],
- sfb_regs[frag_idx_next],
- lane,
- smem_pipe_read_curr,
- k_block_next,
- smem_offset_A,
- smem_offset_B,
- smem_sf_offset,
- smem
- );
-
- if (k_block == 0)
- {
- bool valid = (global_k < k);
- cpasync_load(
- smem_pipe_write,
- global_k,
- smem_offset_A,
- smem_offset_B,
- smem_sf_write_offset,
- lane,
- is_even,
- load_b,
- valid,
- rowA,
- vecB,
- rowS,
- vecS,
- smem);
- asm volatile("cp.async.commit_group;\n" ::);
-
- smem_pipe_write = smem_pipe_read;
- smem_pipe_read = (smem_pipe_read + 1) & 1;
- }
-
- int frag_idx = k_block & 1;
- __half h = block_scaled_fma_16x2fp4(
- a_regs[frag_idx],
- b_regs[frag_idx],
- sfa_regs[frag_idx],
- sfb_regs[frag_idx]);
- sum += __half2float(h);
- }
+ load_block_16x2fp4(
+ rowA, vecB,
+ rowS_u16, vecS_u16,
+ elem_base, block_base,
+ a_regs, b_regs,
+ sfa_regs, sfb_regs);
+ sum += block_scaled_fma_16x2fp4(a_regs, b_regs, sfa_regs, sfb_regs);;
}
- if (tail_stages > 0) {
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
-
- for (int k_block = 0; k_block < tail_stages; ++k_block)
- {
- int frag_idx = k_block & 1;
- int frag_idx_next = (k_block + 1) & 1;
-
- if (k_block < tail_stages - 1) {
- load_fragments(
- a_regs[frag_idx_next],
- b_regs[frag_idx_next],
- sfa_regs[frag_idx_next],
- sfb_regs[frag_idx_next],
- lane,
- smem_pipe_read,
- k_block + 1,
- smem_offset_A,
- smem_offset_B,
- smem_sf_offset,
- smem
- );
- }
-
- __half h = block_scaled_fma_16x2fp4(
- a_regs[frag_idx],
- b_regs[frag_idx],
- sfa_regs[frag_idx],
- sfb_regs[frag_idx]);
- sum += __half2float(h);
- }
+ #pragma unroll
+ for (int offset = THREADS_PER_ROW / 2; offset > 0; offset /= 2) {
+ sum += __shfl_down_sync(0xffffffffu, sum, offset, THREADS_PER_ROW);
}
- asm volatile("cp.async.wait_all;\n" ::);
- __syncthreads();
-
-
- unsigned mask = 0xffffffffu;
- sum += __shfl_down_sync(mask, sum, 8, 16);
- sum += __shfl_down_sync(mask, sum, 4, 16);
- sum += __shfl_down_sync(mask, sum, 2, 16);
- sum += __shfl_down_sync(mask, sum, 1, 16);
-
if (lane == 0) {
__half* out = (__half*)params.o_ptr + C_batch_base + row;
out[0] = __float2half(sum);
}
}
- static inline void launch_kernel_k3584(Gemv_params &params, cudaStream_t stream)
- {
- const int grid_x = (params.m + ROWS_PER_BLOCK - 1) / ROWS_PER_BLOCK;
- size_t smem_size = sizeof(SharedStorage);
- dim3 grid(grid_x, 1, params.b);
- dim3 block(BLOCK_SIZE, 1, 1);
- gemv_kernel_k3584<<<grid, block, smem_size>>>(params);
- }
- // ============================================================================
- // K=256-specialized kernel (your previous v1) -> gemv_kernel_k256 / launch_kernel_k256
- // ============================================================================
-
- __global__ void __launch_bounds__(BLOCK_SIZE, 8)
- gemv_kernel_k256(const __grid_constant__ Gemv_params params)
+ torch::Tensor cuda_nvfp4_gemv(torch::Tensor A,
+ torch::Tensor B,
+ torch::Tensor C,
+ torch::Tensor SFA,
+ torch::Tensor SFB)
{
- const int tid = threadIdx.x;
- const int rib = tid / THREADS_PER_ROW;
- const int lane = tid % THREADS_PER_ROW;
- const int batch = blockIdx.z;
- const int row = blockIdx.x * ROWS_PER_BLOCK + rib;
- const size_t A_batch_base = static_cast<size_t>(batch) * params.a_batch_stride;
- const size_t SFA_batch_base = static_cast<size_t>(batch) * params.sfa_batch_stride;
- const size_t B_batch_base = static_cast<size_t>(batch) * params.b_batch_stride;
- const size_t SFB_batch_base = static_cast<size_t>(batch) * params.sfb_batch_stride;
- const size_t C_batch_base = static_cast<size_t>(batch) * params.o_batch_stride;
+ const auto sizes = A.sizes();
+ const int M = sizes[0];
+ const int K = sizes[1];
+ const int L = sizes[2];
- const __nv_fp4x2_e2m1* rowA = static_cast<const __nv_fp4x2_e2m1*>(params.a_ptr) + A_batch_base + row * params.a_row_stride;
- const __nv_fp8_e4m3* rowS = static_cast<const __nv_fp8_e4m3*>(params.sfa_ptr) + SFA_batch_base + row * params.sfa_row_stride;
-
- const __nv_fp4x2_e2m1* vecB = static_cast<const __nv_fp4x2_e2m1*>(params.b_ptr) + B_batch_base;
- const __nv_fp8_e4m3* vecS = static_cast<const __nv_fp8_e4m3*>(params.sfb_ptr) + SFB_batch_base;
-
- float sum = 0.f;
-
- // Each thread does 1 16 group FP4 or (8 2xFP4)
- for (int idx = 0; idx < params.k / THREADS_PER_ROW / 8; ++idx) {
- int base = idx * 16;
- const int base_id = (idx * THREADS_PER_ROW + lane) * 8;
-
- __nv_fp8_storage_t sfa_storage = *reinterpret_cast<const __nv_fp8_storage_t*>(&rowS[base + lane]);
- __nv_fp8_storage_t sfb_storage = *reinterpret_cast<const __nv_fp8_storage_t*>(&vecS[base + lane]);
- __half sfa = __nv_cvt_fp8_to_halfraw(sfa_storage, __NV_E4M3);
- __half sfb = __nv_cvt_fp8_to_halfraw(sfb_storage, __NV_E4M3);
- __half scale = __hmul(sfa, sfb);
-
- __half2 acc = __float2half2_rn(0.0f);
-
- #pragma unroll
- for (int i = 0; i < 8; ++i) { // go over each individual 2xFP4
- const int id = base_id + i;
- __nv_fp4x2_storage_t a_storage = *reinterpret_cast<const __nv_fp4x2_storage_t*>(&rowA[id]);
- __nv_fp4x2_storage_t b_storage = *reinterpret_cast<const __nv_fp4x2_storage_t*>(&vecB[id]);
- __half2_raw a_raw = __nv_cvt_fp4x2_to_halfraw2(a_storage, __NV_E2M1);
- __half2_raw b_raw = __nv_cvt_fp4x2_to_halfraw2(b_storage, __NV_E2M1);
-
- const __half2 a_h2 = __half2(a_raw);
- const __half2 b_h2 = __half2(b_raw);
-
- acc = __hfma2(a_h2, b_h2, acc);
- }
-
- __half fin = __hadd(__low2half(acc), __high2half(acc));
- __half h = __hmul(fin, scale);
-
- sum += __half2float(h);
- }
-
- // Reduce within the 16-thread subgroup (one output row)
- unsigned mask = 0xffffffffu;
- sum += __shfl_down_sync(mask, sum, 8, 16);
- sum += __shfl_down_sync(mask, sum, 4, 16);
- sum += __shfl_down_sync(mask, sum, 2, 16);
- sum += __shfl_down_sync(mask, sum, 1, 16);
-
- if (lane == 0) {
- __half* out = (__half*)params.o_ptr + C_batch_base + row;
- out[0] = __float2half(sum);
- }
- }
-
- static inline void launch_kernel_k256(Gemv_params &params, cudaStream_t stream)
- {
- const int grid_x = (params.m + ROWS_PER_BLOCK - 1) / ROWS_PER_BLOCK;
- dim3 grid(grid_x, 1, params.b);
- dim3 block(BLOCK_SIZE, 1, 1);
- gemv_kernel_k256<<<grid, block, 0, stream>>>(params);
- }
-
- // ============================================================================
- // Python-facing function: sets up params and dispatches based on K
- // ============================================================================
-
- torch::Tensor nvfp4_gemv_dispatch(torch::Tensor A,
- torch::Tensor B,
- torch::Tensor C,
- torch::Tensor SFA,
- torch::Tensor SFB)
- {
- auto sizes = A.sizes();
- const int64_t M = sizes[0];
- const int64_t K = sizes[1];
- const int64_t L = sizes[2];
-
Gemv_params params{};
- params.b = static_cast<int>(L);
- params.m = static_cast<int>(M);
- params.k = static_cast<int>(K);
- params.real_k = static_cast<int>(K * 2);
+ params.b = L;
+ params.m = M;
+ params.k = K;
- params.a_ptr = A.data_ptr();
- params.b_ptr = B.data_ptr();
- params.sfa_ptr = SFA.data_ptr();
- params.sfb_ptr = SFB.data_ptr();
- params.o_ptr = C.data_ptr();
+ params.a_ptr = A.data_ptr();
+ params.b_ptr = B.data_ptr();
+ params.sfa_ptr= SFA.data_ptr();
+ params.sfb_ptr= SFB.data_ptr();
+ params.o_ptr = C.data_ptr();
- params.a_batch_stride = static_cast<uint64_t>(A.stride(2));
- params.b_batch_stride = static_cast<uint64_t>(B.stride(2));
- params.sfa_batch_stride = static_cast<uint64_t>(SFA.stride(2));
- params.sfb_batch_stride = static_cast<uint64_t>(SFB.stride(2));
- params.o_batch_stride = static_cast<uint64_t>(C.stride(2));
+ params.a_batch_stride = A.stride(2);
+ params.b_batch_stride = B.stride(2);
+ params.sfa_batch_stride= SFA.stride(2);
+ params.sfb_batch_stride= SFB.stride(2);
+ params.o_batch_stride = C.stride(2);
- params.a_row_stride = static_cast<uint64_t>(A.stride(0));
- params.b_row_stride = static_cast<uint64_t>(B.stride(0));
- params.sfa_row_stride = static_cast<uint64_t>(SFA.stride(0));
- params.sfb_row_stride = static_cast<uint64_t>(SFB.stride(0));
- params.o_row_stride = static_cast<uint64_t>(C.stride(0));
+ params.a_row_stride = A.stride(0);
+ params.b_row_stride = B.stride(0);
+ params.sfa_row_stride= SFA.stride(0);
+ params.sfb_row_stride= SFB.stride(0);
+ params.o_row_stride = C.stride(0);
auto stream = at::cuda::getCurrentCUDAStream().stream();
-
- // Tiny host-side dispatch: effectively zero overhead vs kernel time
- if (params.k < 512) {
- launch_kernel_k256(params, stream);
- }
- else if (params.k == 1024) {
- launch_kernel_k1024(params, stream);
+ if (params.k <= 256) { // <= 512 FP4 values
+ dim3 grid(params.m / 16, 1, params.b);
+ dim3 block(128, 1, 1);
+ gemv_kernel<16, 8><<<grid, block, 0, stream>>>(params);
+ } else if (params.k == 3584) {
+ dim3 block(32, 1, 1);
+ dim3 grid(params.m / 4, 1, params.b);
+ gemv_kernel<4, 8><<<grid, block, 0, stream>>>(params);
+ } else if (params.k == 8192) {
+ dim3 block(128, 1, 1);
+ dim3 grid(params.m, 1, params.b);
+ gemv_kernel_shared<1, 128><<<grid, block>>>(params);
+ } else if (params.k == 1024) {
+ dim3 block(64, 1, 1);
+ dim3 grid(params.m / 8, 1, params.b);
+ gemv_kernel<8, 8><<<grid, block, 0, stream>>>(params);
+ } else {
+ dim3 block(128, 1, 1);
+ dim3 grid(params.m / 8, 1, params.b);
+ gemv_kernel<8, 16><<<grid, block, 0, stream>>>(params);
}
- else if (params.k % 1024) {
- launch_kernel_k3584(params, stream);
- }
- else {
- launch_kernel_fast(params, stream);
- }
return C;
}
⋯ 4 unchanged lines
name="nvfp4_gemv",
cpp_sources=[gemv_cpp],
cuda_sources=[gemv_cuda],
- functions=["nvfp4_gemv_dispatch"], # single Python-visible entry point
+ functions=["cuda_nvfp4_gemv"], # this exposes the function to Python
extra_cuda_cflags=[
"-std=c++17",
"-gencode=arch=compute_100a,code=sm_100a",
⋯ 9 unchanged lines
def custom_kernel(data: input_t) -> output_t:
- return nvfp4_module.nvfp4_gemv_dispatch(data[0], data[1], data[6], data[2], data[3])
+ return nvfp4_module.cuda_nvfp4_gemv(data[0], data[1], data[6], data[2], data[3])
scrolls · 1145 diff lines total

Best evidence level for this revision: reported

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