onnxruntime
2cf6c6c6 - [CUDA] Fix QMoE int4/int8 weight prepack to always use SM80 layout (#28978)

Commit
114 days ago
[CUDA] Fix QMoE int4/int8 weight prepack to always use SM80 layout (#28978) ## Summary The CUDA QMoE INT4/INT8 grouped GEMM always dispatches to the Ampere (SM80) CUTLASS kernel — even on Hopper (SM90) — because mixed int-weight + fp16/bf16 activation is not a valid Hopper TMA warp-specialized specialisation. This PR makes weight prepacking always emit the SM80 (column-interleaved) `fpA_intB` layout regardless of the runtime device SM, fixing silently-wrong output on Hopper, and centralizes the arch-clamping logic in a single shared helper. It also cleans up the related tests and tightens MoE parity tolerances that were too loose to catch the layout bug. ## Motivation https://github.com/microsoft/onnxruntime/pull/28749 uses 90 for sm90 weight prepacking. On SM90, `isValidHopperMOESpecialisation<half_t, uint4b_t/uint8_t>()` is `false`, so the grouped MoE GEMM falls back to the SM80 kernel. The weight preprocessor, however, skips column interleaving for `arch == 90`, so an auto-detected (`force_arch=-1`) pack on an H200 produced the non-interleaved SM90 layout that the SM80 kernel cannot consume — yielding wrong results. The previous `PrePackIntExpertWeights` logic clamped to `sm_` (passing SM90 through), and the test that exercised the offline packer used auto-detect, so both could emit the wrong layout. ## Key Changes | Area | Change | |---|---| | `fpA_intB_gemm_preprocessors{.h,_impl.cu}` | Extracted `get_arch_for_mixed_gemm_weight_preprocess(int arch)` as a shared, declared helper (clamps SM to the layout group: `<80→75`, `90→90`, else `80`). | | `fpA_intB_gemm_preprocessors_impl.h` | `getLayoutDetailsForTransform` now routes through the shared helper instead of duplicating the arch-range logic. | | `moe_quantization.cc` (`PrePackIntExpertWeights`) | Always packs INT4/INT8 expert weights for the SM80 layout (`get_arch_for_mixed_gemm_weight_preprocess(80)`) instead of clamping to the runtime `sm_`, since the SM80 kernel runs on every GPU. | | `onnxruntime_pybind_quant.cc` (`PackWeightsForMixedGemm`) | Replaced the ad-hoc `{75,80,90}` allowlist with the shared helper, so `force_arch` is clamped consistently with the runtime dispatch (removes the now-unused `<set>` include). | | `contrib_defs.cc` / `moe_quantization.h` | Updated `weights_prepacked` schema/field docs: layouts for `-1`/`1` are EP-determined; for the CUDA EP `-1` and `1` are equivalent today (both SM80), `1` reserved for a future Hopper-specific layout. | | `test_qmoe_cuda.py` | Removed the dead, never-called `preprocess_weights_for_mixed_gemm` helper; the real path (`quant_dequant_blockwise`) already pins `sm=80`. | | `test_moe_cuda.py` | Pinned the offline packer to `arch=80`, and tightened FP16 QMoE parity tolerance from `atol 3.0 (4-bit)` / `2.0 (8-bit)` to `0.5` now that the layout is correct. | | `docs/` | Regenerated `ContribOperators.md` and updated `moe_qmoe.md` to match the new schema docs and SM80-always packing rationale. | ## Testing Notes On an H200 (SM90), with the CUDA 12.x/13.x Python wheel: ```bash python -m pytest onnxruntime/test/python/transformers/test_qmoe_cuda.py python -m pytest onnxruntime/test/python/transformers/test_moe_cuda.py -k "PhiQMoE or qmoe" ``` - `test_qmoe_cuda.py` SwiGLU parity: SM80 layout → max diff ~0.001 (pass, tol 0.1); the prior SM90 layout produced max diff ~1.2 (fail), confirming the fix. - `test_moe_cuda.py` `TestPhiQMoE` (4-bit and 8-bit, all batch/seq combinations): worst observed `max_diff` ≈ 0.375 with the fixed layout, comfortably under the new `atol=0.5`. - `ruff check` passes on both edited test files. --------- Co-authored-by: tlwu <tlwu@example.com> Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Author
Parents
Loading