[blackwell][draft] sm100: MXFP4 dispatch -> Triton fused_mxfp4_gemm (#227) - #235
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[blackwell][draft] sm100: MXFP4 dispatch -> Triton fused_mxfp4_gemm (#227)#235Andrewxu313 wants to merge 2 commits into
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Placeholder commit for draft PR. Implementation tracked in: batchgen-agent-metadata/batchgen_design/blackwell/blackwell-kernel-port-v1.md Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
On Blackwell the Hopper WGMMA/TMA MXFP4 .cu kernels are not built. Route both MXFP4 MoE paths to the existing pure-Triton fused_mxfp4_gemm kernels: - fused_wgmma_expert.py: is_wgmma_available() returns True on sm100 without loading _C; fused_mxfp4_expert_forward() dispatches to fused_mxfp4_mlp_forward - fused_wgmma_grouped.py: is_grouped_wgmma_available() True on sm100; new fused_mxfp4_grouped_moe_forward_triton() does a per-expert masked loop with fp32 accumulation and slot-specific routing-weight reduction - model.py _grouped_forward: sm100 branch uses the stacked per-expert weight tensors (device-pointer arrays can't be reversed) via the Triton helper Verified on B200: grouped output bit-exact vs per-token reference; expert path matches direct Triton call; no _C_*_mxfp4_wgmma import on sm100. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Closes #227. Part of #204 (Blackwell Phase 2).
Summary
Wire arch=='sm100' in fused_wgmma_grouped.py and fused_wgmma_expert.py to call existing pure-Triton fused_mxfp4_gemm.py. Tune tile sizes for B200 128KB SMEM.
Spec
blackwell-kernel-port-v1.md § Sub-task 4