Commit Graph

2 Commits

Author SHA1 Message Date
a9d5e09f4c B1: mixed FP8/BF16 decode FMHA integration
- New: fmha_mixed_fp8_decode.cuh (Blackwell FP8 tensor-core FMHA kernel)
- New: fmha_mixed_fp8_capi.cu (C ABI launcher)
- New: fmha_mixed_fp8_op.py (Python ctypes/nvcc bridge)
- New: fp8_attention_io.cu (Q quantize + mixed KV gather kernels)
- New: fmha_umma_desc.cuh additions (f8f6f4 UMMA + idesc helpers)
- Modified: production.py (dsv4_attention_mixed_fp8_decode API)
- Modified: single_shot_inference.py (B1 gather + FMHA path)
- Modified: __init__.py (export mixed FP8 API)
- New: docs/B1_MIXED_FP8_FMHA.md, FINAL_STRETCH.md

noPE KV stays FP8_E4M3 + per-row scale, RoPE stays BF16.
No global FP8->BF16 KV staging before FMHA.
Decode-only (T==1), specialized HD=512/NOPE=448/ROPE=64.
CUDA compile/runtime validation pending on B200.
2026-06-02 22:53:14 +00:00
9908fd64d9 feat: CUTLASS NVFP4 mega_moe kernel — slot-based L1/L2, source-first SF remap
Major changes from initial TileLang prototype:

Kernel:
- CUTLASS NVFP4 block-scaled GEMM (SM100 Blackwell, OpClassBlockScaledTensorOp)
- Slot-based dispatch: L1 GEMM → SiLU+Mul per-slot → L2 GEMM → index_add scatter
- 1D slot_expert_ids passed to both L1 and L2 (no 2D topk_ids rebuild)
- slot_token gathered in cutlass_grouped_nvfp4_gemm when provided

SF Remap (source-first):
- Iterates logical (m, k_sf) source grid, uses layout_sf(make_coord(m, k_sf))
  for CUTLASS dest index — no idx2crd/flatten coordinate extraction
- 2D kernel launch: dim3 block(32,8), grid over (K_sf, MN)
- Uses cute::cosize() for physical allocation size (not cute::size)
- SFA: (MN, K_sf) row-major; SFB: (K_sf, MN) row-major (col-major)

Weight transform:
- UE4M3 unpack with bit reinterpret (not value cast)
- Global scale folding (weight_scale_2) for gate/up split
- clamp(0,448) → float8_e4m3fn, transpose (N,K)→(K,N) for CUTLASS

No prepack cache:
- SFB remapped per-call inside CUTLASS (~µs, not the bottleneck)
- See README for why prepack cache must never return (OOM, CUDA graphs,
  M-dependent layout, cross-layer collisions)

Stage activation:
- Nearest-neighbor E2M1 quantization (no clamp, no uniform steps)
- Per-tensor global scale → alpha for L2 GEMM

Bug fixes:
- _fold_global_scale: removed broken logical_widths branch
- unpack_ue4m3_u32: int32 for CUDA bitwise, view not to, ND support
- Correct expert param mapping for NVFP4 checkpoint
- SiLU applied per-slot (not after summing expert paths)
2026-05-15 11:38:18 +00:00