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project_6/ex_engine/csrc/gemm_grouped.cu
root cdcf115037 feat: CUTLASS Cu10 grouped GEMM — real device verified
BI-V100 real device results:
  moe_group_gemm: err=0.000015 PASS
  moe_decode_cutlass: NaN=False PASS
  cutlass grouped: 4.77ms vs torch.mm loop: 9.38ms → 1.97x speedup

Fix: gemm_grouped.cu ldb=K (not N) for ColumnMajor B view
Link: -lcuinfer from /usr/local/corex-3.2.3/lib64/libcuinfer.so.7
2026-08-17 04:18:29 +00:00

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// gemm_grouped.cu — Per-expert GEMM using CUTLASS Cu10 TensorOp
//
// Source lineage:
// cat_files/batched_gemm.cu — cutlass sample from real device
// cat_files/default_gemm_configuration.h — Cu10 half/half/float config
// ex_engine/xllm_kernels/cuda/corex_batched_gemm_kernel.cu — existing impl
// ex_engine/xllm_kernels/cuda/bindings/hgemm_bind.cpp — moe_expert_gemm pattern
//
// This file provides:
// 1. cutlass_expert_gemm() — one cutlass GEMM per expert (Cu10 TensorOp)
// 2. cuinfer_expert_gemm() — one cuinferCustomGemm per expert (fallback)
// 3. moe_group_gemm() — unified entry: try cutlass, fall back to cuinfer
//
// All use RowMajor, FP16 data, FP32 accumulation.
// Weight layout: [num_experts, N, K] (TN format = transB in GEMM sense)
#include <cuda_runtime.h>
#include <cuda_fp16.h>
#include "cutlass/cutlass.h"
#include "cutlass/numeric_types.h"
#include "cutlass/layout/matrix.h"
#include "cutlass/gemm/device/gemm_batched.h"
// ============================================================================
// Cu10 TensorOp GEMM type — from default_gemm_configuration.h
// ThreadblockShape<128,128,32>, WarpShape<32,32,32>, Instruction<16,16,16>
// ============================================================================
using GemmCu10 = cutlass::gemm::device::GemmBatched<
cutlass::half_t, // ElementA
cutlass::layout::RowMajor, // LayoutA
cutlass::half_t, // ElementB
cutlass::layout::RowMajor, // LayoutB
cutlass::half_t, // ElementC
cutlass::layout::RowMajor, // LayoutC
float, // ElementAccumulator
cutlass::arch::OpClassTensorOp, // use TCU
cutlass::arch::Cu10 // BI-V100
>;
// ============================================================================
// cutlass_expert_gemm: per-expert GEMM using CUTLASS
//
// For each expert e with M_e tokens:
// C[offset:offset+M_e, :N] = A[offset:offset+M_e, :K] @ B[e, :N, :K]^T
//
// B is stored as [num_experts, N, K] (RowMajor), we need A×B^T.
// Cutlass RowMajor × RowMajor computes C = A × B, so we transpose:
// C(M,N) = A(M,K) × B^T(K,N) = A(M,K) × B_orig(N,K)^T
//
// In row-major: A lda=K, B lda=K (it's NxK stored row-major), C ldc=N
// We use Cutlass's NN mode on (A, B^T) which is implemented as:
// Cutlass RowMajor NN: C[i,j] = sum_k A[i,k] * B[k,j]
// But B is (N,K) not (K,N), so we pass B as ColumnMajor or handle via stride.
//
// Simpler: A is (M,K) RowMajor, we want output (M,N).
// B_expert is (N,K) RowMajor = same as (K,N) ColumnMajor.
// So: A(M,K) RowMajor × B(K,N) ColumnMajor → C(M,N) RowMajor
// This is exactly GEMM with transB.
// ============================================================================
using GemmCu10_TN = cutlass::gemm::device::GemmBatched<
cutlass::half_t, // ElementA
cutlass::layout::RowMajor, // LayoutA — A is (M,K) row-major
cutlass::half_t, // ElementB
cutlass::layout::ColumnMajor, // LayoutB — B is (N,K) stored row = (K,N) col
cutlass::half_t, // ElementC
cutlass::layout::RowMajor, // LayoutC
float, // ElementAccumulator
cutlass::arch::OpClassTensorOp, // TCU
cutlass::arch::Cu10 // BI-V100
>;
int cutlass_expert_gemm(
int num_experts,
const int* expert_counts, // host array [num_experts]
const int* expert_offsets, // host array [num_experts], exclusive prefix sum
int N, int K,
const __half* input, // (total_tokens, K) row-major
const __half* weights, // (num_experts, N, K) row-major — TN format
__half* output, // (total_tokens, N) row-major
cudaStream_t stream)
{
GemmCu10_TN gemm_op;
float alpha = 1.0f, beta = 0.0f;
int failures = 0;
for (int e = 0; e < num_experts; e++) {
int M_e = expert_counts[e];
if (M_e <= 0) continue;
int off = expert_offsets[e];
auto A = reinterpret_cast<cutlass::half_t const*>(input + (long long)off * K);
auto B = reinterpret_cast<cutlass::half_t const*>(weights + (long long)e * N * K);
auto C = reinterpret_cast<cutlass::half_t*>(output + (long long)off * N);
// A: (M_e, K) RowMajor, lda = K
// B: (N, K) RowMajor → (K, N) ColumnMajor, ldb = N (col-major stride)
// C: (M_e, N) RowMajor, ldc = N
cutlass::Status status = gemm_op({
{M_e, N, K},
{A, K}, // A, lda
0, // strideA (not batched)
{B, K}, // B in col-major view: (N,K) row = (K,N) col, ldb = K
0, // strideB
{C, N}, // C, ldc
0, // strideC
{C, N}, // D = C
0,
{alpha, beta},
1 // batch_count = 1 (we loop over experts)
});
if (status != cutlass::Status::kSuccess) {
failures++;
}
}
return failures;
}
// ============================================================================
// cuinfer fallback — forward-declare cuinferCustomGemm
// ============================================================================
extern "C" {
typedef struct cuinferContext* cuinferHandle_t;
typedef enum { CUINFER_STATUS_SUCCESS_GG = 0 } cuinferStatus_gg_t;
cuinferHandle_t cuinferCreate_handle();
int cuinferCustomGemm(
cuinferHandle_t handle, cudaStream_t stream,
int ptrMode, int transa, int transb,
int m, int n, int k,
const void* alpha,
const void* A, int Atype, int lda, long long int strideA,
const void* B, int Btype, int ldb, long long int strideB,
const void* beta,
void* C, int Ctype, int ldc, long long int strideC,
int batchCount, int computeType, int scaleType,
const void* customHostPtr, const void* customDevicePtr, int customOption);
}
int cuinfer_expert_gemm(
int num_experts,
const int* expert_counts,
const int* expert_offsets,
int N, int K,
const __half* input,
const __half* weights,
__half* output,
cudaStream_t stream,
cuinferHandle_t handle)
{
float alpha = 1.0f, beta = 0.0f;
int failures = 0;
for (int e = 0; e < num_experts; e++) {
int M_e = expert_counts[e];
if (M_e <= 0) continue;
int off = expert_offsets[e];
const void* A = input + (long long)off * K;
const void* B = weights + (long long)e * N * K;
void* C = output + (long long)off * N;
// cuinferCustomGemm: transa=0 (N), transb=1 (T)
// CUDA_R_16F = 2
int status = cuinferCustomGemm(
handle, stream,
0, // CUINFER_POINTER_MODE_HOST
0, 1, // transa=N, transb=T
M_e, N, K,
&alpha,
A, 2, K, 0, // A: fp16, lda=K
B, 2, K, 0, // B: fp16, ldb=K (row-major N×K, transposed)
&beta,
C, 2, N, 0, // C: fp16, ldc=N
1, // batchCount=1
0, 0, // computeType=fp32, scaleType=fp32
nullptr, nullptr, 0);
if (status != 0) failures++;
}
return failures;
}