#include #include #include typedef unsigned short bf16_t; int main() { printf("=== TMA 5D + Interleave test ===\n"); bf16_t* d_data; cudaMalloc(&d_data, 128*16*2 + 256); uint64_t addr = ((uint64_t)d_data + 255) & ~255ULL; bf16_t* d_aligned = (bf16_t*)addr; printf("ptr: %p (256B aligned)\n", d_aligned); CUtensorMap tma; CUresult r; // Approach: 5D descriptor with padded dimensions // V is (hd=16, s_k=128) in row-major → 16 rows of 128 cols // As a TMA tensor: innermost dim is the contiguous dimension // For row-major: dim[0] = cols (innermost), dim[1] = rows // globalDim: [16, 128, 1, 1, 1] → 5D // globalStrides (bytes, tensorRank-1=4): [2, 256, 256*128, 256*128, 256*128] // But element strides must be <= 8: // elementStride[0] = 1 (cols), elementStride[1] = 16 (row stride in elements) // 16 > 8 → INVALID // With INTERLEAVE_16B: each element is treated as 16-byte blocks // This changes the stride calculation // elementStride with interleave: stride is in 16-byte blocks, not elements // [1, 1] → 1 interleave-block stride in x, 1 interleave-block stride in y // Try: 5D with INTERLEAVE_16B { // For (128, 16) BF16 matrix in row-major: // 128 rows × 16 cols × 2 bytes = 4096 bytes // With INTERLEAVE_16B, we load 16-byte (8 BF16) chunks // Tile: (8 cols, 128 rows) in 16-byte chunks = 128 chunks per tile // Actually, let me just try different interleave modes // 5D global dim: [16, 128, 1, 1, 1] // 5D global stride (bytes, 4 elements): [2, 256, 256*128, 256*128, 256*128] // 5D tile dim: [16, 128, 1, 1, 1] // 5D tile stride: [1, 16, 16*128, 16*128, 16*128] uint64_t gdim[] = {16, 128, 1, 1, 1}; uint64_t gstr[] = {2, 256, 32768, 32768, 32768}; uint32_t tdim[] = {16, 128, 1, 1, 1}; uint32_t tstr[] = {1, 16, 2048, 2048, 2048}; r = cuTensorMapEncodeTiled(&tma, CU_TENSOR_MAP_DATA_TYPE_BFLOAT16, 5, d_aligned, gdim, gstr, tdim, tstr, CU_TENSOR_MAP_INTERLEAVE_NONE, CU_TENSOR_MAP_SWIZZLE_NONE, CU_TENSOR_MAP_L2_PROMOTION_NONE, CU_TENSOR_MAP_FLOAT_OOB_FILL_NONE); printf("5D NONE: result=%d\n", r); } // Try with SWIZZLE_128B { uint64_t gdim[] = {16, 128, 1, 1, 1}; uint64_t gstr[] = {2, 256, 32768, 32768, 32768}; uint32_t tdim[] = {16, 128, 1, 1, 1}; uint32_t tstr[] = {1, 16, 2048, 2048, 2048}; r = cuTensorMapEncodeTiled(&tma, CU_TENSOR_MAP_DATA_TYPE_BFLOAT16, 5, d_aligned, gdim, gstr, tdim, tstr, CU_TENSOR_MAP_INTERLEAVE_NONE, CU_TENSOR_MAP_SWIZZLE_128B, CU_TENSOR_MAP_L2_PROMOTION_NONE, CU_TENSOR_MAP_FLOAT_OOB_FILL_NONE); printf("5D SWIZZLE_128B: result=%d\n", r); } // Try with smaller tile dims that have strides <= 8 // Tile (8, 8) with stride [1, 16] → stride[1] = 16 > 8 STILL FAILS // Tile (16, 1) with stride [1, 16] → stride[1] = 16 > 8 // Actually, let me check: is elementStrides in ELEMENTS or BYTES? // If in bytes: stride[1] = 16 elements * 2 bytes = 32 → still > 8 // I think the element strides constraint is the FUNDAMENTAL issue // For row-major (128, 16) BF16, row stride = 16 elements > 8 // There is NO way to make this work with 2D TMA for this layout // The CUTLASS solution: they use K-major (column-major) tensors // In K-major, the innermost dimension is K (contiguous), stride = 1 // This works because the MMA also reads K-major data // For V in K-major: (K=128, N=16) → stride between N elements = 128 elements // elementStrides = [1, 128] → 128 >> 8 → STILL FAILS! // But wait: CUTLASS decomposes 128 = 8 * 16 // In 5D: (8, 16, 1, 1, 16) with strides [1, 8, 128, 128, 128] // elementStrides = [1, 8, 16, 16, 16] → ALL ≤ 16 but not ≤ 8 // Hmm. Let me try with strides that are all <= 8 // 128 = 2^7 = 8 * 16 = 4 * 32 = ... // (8, 16, 1, 1, 16) → strides [1, 8, 128, 128, 128] // elementStrides = [1, 8, 16, 16, 16] // 8 is the max, and stride[1] = 8 is OK, but stride[2] = 16 > 8 // Need: (8, 8, 2, 1, 16) → strides [1, 8, 64, 128, 128] // elementStrides = [1, 8, 8, 16, 16] → stride[3] = 16 > 8 // (8, 8, 8, 1, 2) → strides [1, 8, 64, 512, 512] // elementStrides = [1, 8, 8, 8, 1] → ALL <= 8! // This would mean: dim = [8, 8, 8, 1, 2], total = 8*8*8*1*2 = 1024 elements // But our tensor is 128*16 = 2048 elements (2x too big) // (8, 8, 8, 1, 4) → total = 2048, strides = [1, 8, 64, 512, 2048] // elementStrides = [1, 8, 8, 8, 4] → ALL <= 8! // This works! { // 5D descriptor for (128, 16) BF16 in K-major (col-major) // Decomposition: (8, 8, 8, 1, 4) // Total elements: 8*8*8*1*4 = 2048 = 128*16 ✓ // elementStrides: [1, 8, 8, 8, 4] → all ≤ 8 ✓ // globalStrides (bytes): [2, 16, 128, 1024, 1024] uint64_t gdim[] = {8, 8, 8, 1, 4}; uint64_t gstr[] = {2, 16, 128, 1024, 1024}; uint32_t tdim[] = {8, 8, 8, 1, 4}; uint32_t tstr[] = {1, 8, 64, 512, 512}; r = cuTensorMapEncodeTiled(&tma, CU_TENSOR_MAP_DATA_TYPE_BFLOAT16, 5, d_aligned, gdim, gstr, tdim, tstr, CU_TENSOR_MAP_INTERLEAVE_NONE, CU_TENSOR_MAP_SWIZZLE_NONE, CU_TENSOR_MAP_L2_PROMOTION_NONE, CU_TENSOR_MAP_FLOAT_OOB_FILL_NONE); printf("5D (8,8,8,1,4) strides [1,8,8,8,4]: result=%d\n", r); } cudaFree(d_data); return 0; }