add MXFP8 pre-swizzling for gfx1250 GEMM

tests/cpp/operator/CMakeLists.txt

@@ -31,11 +31,11 @@ list(APPEND test_cuda_sources
             test_multi_unpadding.cu
             test_causal_softmax.cu
             test_swap_first_dims.cu
+            test_swizzle.cu
 	          ../test_common.cu)
 if(USE_CUDA)
   list(APPEND test_cuda_sources
-              test_cast_float8blockwise.cu
-              test_swizzle.cu)
+              test_cast_float8blockwise.cu)
 else()
   list(APPEND test_cuda_sources
               test_cublaslt_gemm.cu

tests/cpp/operator/test_cublaslt_gemm.cu

@@ -11,6 +11,7 @@
 #include <gtest/gtest.h>
 #include <transformer_engine/cast.h>
 #include <transformer_engine/gemm.h>
+#include <transformer_engine/swizzle.h>
 #include <transformer_engine/transformer_engine.h>
 #include "../test_common.h"
 
@@ -793,4 +794,228 @@ TEST(InputGenTest, FillUniform_DoesNotGetOverwrittenByFromCpu) {
   }
 }
 
+// ============================================================================
+// End-to-end MXFP8 GEMM test with pre-swizzled scales
+//
+// Verifies that the full pipeline works:
+//   1. Create MXFP8 FP8 tensors with random data + scales
+//   2. Run a reference GEMM (using un-swizzled scales)
+//   3. Swizzle the scales via nvte_swizzle_scaling_factors
+//   4. Run the actual hipBLASlt GEMM
+//   5. Compare results
+// ============================================================================
+
+// Helper: swizzle the MXFP8 scale_inv of a test::Tensor in-place.
+// Allocates a temp device buffer, swizzles into it, copies back.
+static void swizzle_tensor_scales(test::Tensor &t, bool rowwise) {
+  using namespace transformer_engine;
+
+  void *scale_ptr = rowwise ? t.rowwise_scale_inv_dptr()
+                            : t.columnwise_scale_inv_dptr();
+  if (!scale_ptr)
+    return;
+
+  const NVTEShape scale_shape = rowwise ? t.rowwise_scale_inv_shape()
+                                        : t.columnwise_scale_inv_shape();
+  const NVTEShape data_shape = rowwise ? t.rowwise_shape()
+                                       : t.columnwise_shape();
+
+  size_t num_scales = 1;
+  for (size_t d = 0; d < scale_shape.ndim; d++) {
+    num_scales *= scale_shape.data[d];
+  }
+
+  // Allocate temp buffer for swizzled output
+  uint8_t *d_tmp = nullptr;
+  NVTE_CHECK_CUDA(cudaMalloc(&d_tmp, num_scales));
+
+  // Build TensorWrapper pair for the swizzle call
+  TensorWrapper input_tw(NVTE_MXFP8_1D_SCALING);
+  TensorWrapper output_tw(NVTE_MXFP8_1D_SCALING);
+  output_tw.set_with_gemm_swizzled_scales(true);
+
+  if (rowwise) {
+    input_tw.set_rowwise_data(nullptr, t.dtype(), data_shape);
+    input_tw.set_rowwise_scale_inv(scale_ptr, DType::kFloat8E8M0, scale_shape);
+    output_tw.set_rowwise_data(nullptr, t.dtype(), data_shape);
+    output_tw.set_rowwise_scale_inv(d_tmp, DType::kFloat8E8M0, scale_shape);
+  } else {
+    input_tw.set_columnwise_data(nullptr, t.dtype(), data_shape);
+    input_tw.set_columnwise_scale_inv(scale_ptr, DType::kFloat8E8M0, scale_shape);
+    output_tw.set_columnwise_data(nullptr, t.dtype(), data_shape);
+    output_tw.set_columnwise_scale_inv(d_tmp, DType::kFloat8E8M0, scale_shape);
+  }
+
+  nvte_swizzle_scaling_factors(input_tw.data(), output_tw.data(), 0);
+  NVTE_CHECK_CUDA(cudaDeviceSynchronize());
+
+  // Copy swizzled scales back over the original
+  NVTE_CHECK_CUDA(cudaMemcpy(scale_ptr, d_tmp, num_scales, cudaMemcpyDeviceToDevice));
+  NVTE_CHECK_CUDA(cudaFree(d_tmp));
+
+  // Mark tensor as having swizzled scales
+  t.set_with_gemm_swizzled_scales(true);
+}
+
+// Simple GPU reference kernel for MXFP8 GEMM: D = A * B^T  (TN layout)
+// A is [M, K] row-major, B is [N, K] row-major, D is [M, N] column-major
+// Scales are E8M0, one per group of 32 elements along K.
+__global__ void mxfp8_gemm_ref_kernel(
+    const test::fp8e4m3 *a_data, const uint8_t *a_scale, size_t a_scale_ld,
+    const test::fp8e4m3 *b_data, const uint8_t *b_scale, size_t b_scale_ld,
+    test::bf16 *d_data,
+    size_t M, size_t K, size_t N) {
+  const size_t i = blockIdx.y * blockDim.y + threadIdx.y;
+  const size_t j = blockIdx.x * blockDim.x + threadIdx.x;
+
+  if (i >= M || j >= N)
+    return;
+
+  float acc = 0.0f;
+
+  for (size_t kk = 0; kk < K; kk++) {
+    size_t kc = kk / 32;
+    float a_sinv = exp2f(static_cast<float>(a_scale[i * a_scale_ld + kc]) - 127.0f);
+    float b_sinv = exp2f(static_cast<float>(b_scale[j * b_scale_ld + kc]) - 127.0f);
+    float a_val = static_cast<float>(a_data[i * K + kk]);
+    float b_val = static_cast<float>(b_data[j * K + kk]);
+    acc += a_sinv * a_val * b_sinv * b_val;
+  }
+
+  d_data[i + j * M] = static_cast<test::bf16>(acc);
+}
+
+struct MxGemmParams {
+  size_t m, k, n;
+};
+
+class MxGemmSwizzleGfx1250TestSuite
+    : public ::testing::TestWithParam<MxGemmParams> {};
+
+TEST_P(MxGemmSwizzleGfx1250TestSuite, TestMxfp8GemmE2E) {
+  using namespace transformer_engine;
+  using namespace test;
+
+  const auto &p = GetParam();
+  const size_t M = p.m;
+  const size_t K = p.k;
+  const size_t N = p.n;
+
+  cudaDeviceProp prop;
+  NVTE_CHECK_CUDA(cudaGetDeviceProperties(&prop, 0));
+
+  // This test validates the MX scale pre-swizzle -> GEMM pipeline on gfx1250+.
+  // Non-swizzle MXFP8 GEMMs are already covered by GEMMTestSuite.
+  if (prop.major < 12) {
+    GTEST_SKIP() << "MX scale pre-swizzle GEMM requires gfx1250+";
+  }
+
+  // TN layout: A is [M, K], B is [N, K]
+  const bool transa = true;
+  const bool transb = false;
+
+  Tensor A("A", std::vector<size_t>{M, K}, DType::kFloat8E4M3, true, false, NVTE_MXFP8_1D_SCALING);
+  Tensor B("B", std::vector<size_t>{N, K}, DType::kFloat8E4M3, true, false, NVTE_MXFP8_1D_SCALING);
+  Tensor D("D", std::vector<size_t>{N, M}, DType::kBFloat16);
+  Tensor RefD("RefD", std::vector<size_t>{N, M}, DType::kBFloat16);
+  Tensor bias;
+  Tensor pre_gelu_out;
+
+  fillUniform(&A);
+  fillUniform(&B);
+
+  // Override scales with values in [120,127] so layout errors are detectable.
+  // Default random [0,127] produces mostly tiny scales (2^(-127)..2^0),
+  // making the test insensitive to permutation errors.
+  {
+    auto fill_discriminating_scales = [](void *scale_ptr, size_t count) {
+      std::vector<uint8_t> h(count);
+      std::mt19937 rng(42);
+      std::uniform_int_distribution<uint8_t> dist(120, 127);
+      for (size_t i = 0; i < count; i++)
+        h[i] = dist(rng);
+      NVTE_CHECK_CUDA(cudaMemcpy(scale_ptr, h.data(), count, cudaMemcpyHostToDevice));
+    };
+    auto a_sh = A.rowwise_scale_inv_shape();
+    auto b_sh = B.rowwise_scale_inv_shape();
+    fill_discriminating_scales(A.rowwise_scale_inv_dptr(), a_sh.data[0] * a_sh.data[1]);
+    fill_discriminating_scales(B.rowwise_scale_inv_dptr(), b_sh.data[0] * b_sh.data[1]);
+  }
+
+  // GPU reference with un-swizzled (compact) scales
+  const auto a_scale_shape = A.rowwise_scale_inv_shape();
+  const auto b_scale_shape = B.rowwise_scale_inv_shape();
+
+  std::cout << "  A_scale shape: [" << a_scale_shape.data[0] << ", " << a_scale_shape.data[1]
+            << "], B_scale shape: [" << b_scale_shape.data[0] << ", " << b_scale_shape.data[1]
+            << "]" << std::endl;
+
+  {
+    dim3 block(16, 16);
+    dim3 grid((N + block.x - 1) / block.x, (M + block.y - 1) / block.y);
+    mxfp8_gemm_ref_kernel<<<grid, block>>>(
+        static_cast<const fp8e4m3 *>(A.rowwise_dptr()),
+        static_cast<const uint8_t *>(A.rowwise_scale_inv_dptr()),
+        a_scale_shape.data[1],
+        static_cast<const fp8e4m3 *>(B.rowwise_dptr()),
+        static_cast<const uint8_t *>(B.rowwise_scale_inv_dptr()),
+        b_scale_shape.data[1],
+        static_cast<bf16 *>(RefD.rowwise_dptr()),
+        M, K, N);
+    NVTE_CHECK_CUDA(cudaDeviceSynchronize());
+  }
+
+  // Swizzle scales to K-tiled layout for hipBLASlt BLK32_UE8M0_32_8_EXT on gfx1250.
+  // Layout: {M, K_scale}.reshape({M, K_scale/4, 4}).permute({1,0,2})
+  //   dst(m,k) = (k/4)*M*4 + m*4 + (k%4)
+  swizzle_tensor_scales(A, true);
+  swizzle_tensor_scales(B, true);
+
+  // Run actual GEMM
+  size_t workspace_size = 134217728;  // 128MB
+  Tensor Workspace("Workspace", std::vector<size_t>{workspace_size}, DType::kByte);
+
+  nvte_cublas_gemm(A.data(), B.data(), D.data(),
+                   bias.data(), pre_gelu_out.data(),
+                   transa, transb,
+                   /*grad=*/false,
+                   Workspace.data(),
+                   /*accumulate=*/false,
+                   /*use_split_accumulator=*/false,
+                   prop.multiProcessorCount,
+                   0);
+
+  NVTE_CHECK_CUDA(cudaDeviceSynchronize());
+
+  // Compare
+  D.to_cpu();
+  RefD.to_cpu();
+
+  // MXFP8 accumulation errors grow with K due to different reduction orders
+  // between hardware and reference kernels.
+  const double atol = 5e-2 + K * 2e-4;
+  const double rtol = 1.5e-2;
+  compareResults("D", D, RefD.rowwise_cpu_dptr<bf16>(), true, atol, rtol);
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    OperatorTest,
+    MxGemmSwizzleGfx1250TestSuite,
+    ::testing::Values(
+        MxGemmParams{32, 128, 16},
+        MxGemmParams{64, 128, 32},
+        MxGemmParams{128, 128, 64},
+        MxGemmParams{64, 256, 32},
+        MxGemmParams{128, 384, 64},
+        MxGemmParams{256, 512, 128},
+        MxGemmParams{512, 1024, 256},
+        MxGemmParams{1024, 2048, 128},
+        MxGemmParams{4096, 8192, 64}
+    ),
+    [](const testing::TestParamInfo<MxGemmSwizzleGfx1250TestSuite::ParamType> &info) {
+      return "M" + std::to_string(info.param.m) +
+             "_K" + std::to_string(info.param.k) +
+             "_N" + std::to_string(info.param.n);
+    });
+
 #endif  // __HIP_PLATFORM_AMD__