Unify MoE CuTe DSL dispatch to be dtype agnostic - #4793
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Consolidate W4A4 and W4A8 on the dtype-agnostic blockscaled API and fused_moe backend while retaining warning aliases for deprecated dtype-specific APIs. BREAKING CHANGE: use cute_dsl_fused_moe, CuteDslMoEWrapper, and quant_mode="w4a4" or "w4a8" instead of dtype-specific APIs.
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Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review. 📝 WalkthroughWalkthroughCuTe DSL fused MoE support is unified across W4A4, W4A8, and W4A16 modes. The change adds MXFP4 weight preparation and MXFP8 dispatch packing, renames APIs and backend keys, preserves compatibility aliases, removes the dedicated SM100 split path, and updates tests and documentation. ChangesUnified CuTe DSL MoE support
Estimated code review effort: 4 (Complex) | ~60 minutes Merge Risk: ⚪ Minimal · up to The PR consolidates dtype-agnostic MoE dispatch and compatibility APIs; no actionable merge-blocking risk remains after normal checks and review. Sequence Diagram(s)sequenceDiagram
participant BF16Tokens
participant FusedMoeSplitKernelBackend
participant pack_mxfp8_dispatch_payload
participant build_activation_pack
participant cute_dsl_fused_moe
BF16Tokens->>FusedMoeSplitKernelBackend: submit activation rows
FusedMoeSplitKernelBackend->>pack_mxfp8_dispatch_payload: pack MXFP8 values and scales
pack_mxfp8_dispatch_payload->>build_activation_pack: provide packed dispatch rows
build_activation_pack->>cute_dsl_fused_moe: pass MXFP4 activation pack and scales
cute_dsl_fused_moe-->>FusedMoeSplitKernelBackend: return fused MoE output
Suggested reviewers: 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
Full details: Docstring CoverageExplanation Docstring coverage is 50.43% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 117 functions across 28 files. (2 skipped: 2 unsupported.) Full details: Description checkExplanation The description follows the repository template and explains the API consolidation, compatibility behavior, removed duplicate implementation, platform support, and test coverage. However, it states that the complete repository test suite was run, while the PR objectives state that it was not run.
✨ Finishing Touches 💡 1🛠️ Fix failing CI checks 💡
🧪 Generate unit tests (beta)
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🚨 POTENTIAL BREAKING PUBLIC API CHANGE DETECTED 🚨Caution THIS PR APPEARS TO BREAK THE PUBLIC API. AUTHORS AND REVIEWERS: DO NOT MISS THIS. This is an advisory warning and does not gate merging. Confirm compatibility and provide a deprecation or migration path, or track the fix in a follow-up PR. 4 public API finding(s):
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Inline comments:
In `@flashinfer/fused_moe/cute_dsl/fused_moe.py`:
- Around line 645-646: Add a trace template for CuteDslMoEWrapper.__init__ and
provide it through the flashinfer_api decorator’s trace= argument, replacing the
bare decorator. Include the constructor’s relevant parameters so fi_trace() and
benchmark-definition dumping work for this public API.
- Around line 1146-1147: Update the cute_dsl_fused_moe docstring to add a tactic
parameter entry, reusing the same description already documented by
CuteDslMoEWrapper.run.
- Around line 157-173: Update the W4A8 validation around x_sf, w1_weight_sf, and
w2_weight_sf to require torch.uint8 dtype in addition to the existing shape and
stride checks. Raise a clear TypeError for any invalid scale tensor before the
generic GEMM executes, while preserving the current validation for
token_final_scales and tensor layouts.
In `@flashinfer/trace/templates/moe.py`:
- Around line 3637-3639: Update the W4A8 scale tensor descriptors in
cute_dsl_fused_moe_trace, including w1_weight_sf and its corresponding scale
tensor, to match the six-dimensional MMA layout emitted by
convert_sf_to_mma_layout, ensuring axis extraction uses the MMA block dimensions
rather than the current three-dimensional logical shape.
In `@tests/moe/test_unified_moe.py`:
- Line 1105: Update the pytest.raises assertion’s match argument to use a raw
regular-expression literal, preserving the existing W4A8.*SM107 pattern and
NotImplementedError expectation.
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benchmarks/bench_cute_dsl_moe_distributed.pybenchmarks/bench_moe_deepseek.pybenchmarks/routines/moe.pydocs/api/fused_moe.rstdocs/design_docs/moe_ep_architecture.mdflashinfer/__init__.pyflashinfer/fused_moe/__init__.pyflashinfer/fused_moe/api.pyflashinfer/fused_moe/cute_dsl/__init__.pyflashinfer/fused_moe/cute_dsl/_inputs_helper.pyflashinfer/fused_moe/cute_dsl/blockscaled_contiguous_gather_grouped_gemm_act_fusion.pyflashinfer/fused_moe/cute_dsl/blockscaled_contiguous_grouped_gemm_finalize_fusion.pyflashinfer/fused_moe/cute_dsl/fused_moe.pyflashinfer/fused_moe/cute_dsl/fused_moe_mxfp8_mxfp4.pyflashinfer/fused_moe/cute_dsl/mixed_tuner.pyflashinfer/fused_moe/cute_dsl/tuner.pyflashinfer/fused_moe/layer.pyflashinfer/fused_moe/prepare.pyflashinfer/fused_moe/runners.pyflashinfer/moe_ep/__init__.pyflashinfer/moe_ep/backends/split/kernel/__init__.pyflashinfer/moe_ep/backends/split/kernel/fused_moe/backend.pyflashinfer/moe_ep/backends/split/kernel/fused_moe/bridge.pyflashinfer/moe_ep/backends/split/kernel/fused_moe/config.pyflashinfer/moe_ep/backends/split/kernel/fused_moe/weights.pyflashinfer/moe_ep/backends/split/kernel/sm100/__init__.pyflashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/__init__.pyflashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/backend.pyflashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/config.pyflashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/weights.pyflashinfer/moe_ep/modes/__init__.pyflashinfer/trace/templates/moe.pyscripts/pr_checks/check_api_docs.pytests/moe/test_cute_dsl_fused_moe.pytests/moe/test_cute_dsl_moe_can_implement.pytests/moe/test_cute_dsl_mxfp8_mxfp4_fused_moe.pytests/moe/test_cute_dsl_mxfp8_mxfp4_grouped_gemm.pytests/moe/test_unified_moe.pytests/moe/test_unified_moe_fuzz.pytests/moe_ep/test_compute_bridge.pytests/moe_ep/test_moe_ep_mxfp8_dispatch_multirank.pytests/moe_ep/test_mxfp8_mxfp4_cutedsl_split_kernel.pytests/moe_ep/test_split_kernels.pytests/trace/template_registry.py
💤 Files with no reviewable changes (14)
- tests/trace/template_registry.py
- tests/moe/test_cute_dsl_mxfp8_mxfp4_fused_moe.py
- flashinfer/moe_ep/init.py
- tests/moe_ep/test_mxfp8_mxfp4_cutedsl_split_kernel.py
- flashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/config.py
- flashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/weights.py
- flashinfer/moe_ep/modes/init.py
- flashinfer/moe_ep/backends/split/kernel/sm100/init.py
- flashinfer/fused_moe/cute_dsl/mixed_tuner.py
- flashinfer/fused_moe/cute_dsl/fused_moe_mxfp8_mxfp4.py
- tests/moe_ep/test_moe_ep_mxfp8_dispatch_multirank.py
- flashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/backend.py
- tests/moe/test_cute_dsl_mxfp8_mxfp4_grouped_gemm.py
- flashinfer/moe_ep/backends/split/kernel/sm100/mxfp8_mxfp4_bf16_cutedsl/init.py
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Inline comments:
In `@flashinfer/fused_moe/cute_dsl/fused_moe.py`:
- Around line 1375-1377: Add compatible trace templates via trace= to all four
public compatibility APIs: cute_dsl_fused_moe_nvfp4
(flashinfer/fused_moe/cute_dsl/fused_moe.py lines 1375-1377),
cute_dsl_fused_moe_mxfp8_mxfp4 (lines 1450-1452), CuteDslMxfp8Mxfp4MoEWrapper’s
constructor (lines 1530-1531), and CuteDslMxfp8Mxfp4MoEWrapper.run (line 1578).
Use function trace templates for the APIs and a constructor trace template for
the wrapper so fi_trace() and benchmark-definition dumping work consistently.
- Around line 1418-1447: Emit a DeprecationWarning at
flashinfer/fused_moe/cute_dsl/fused_moe.py lines 1418-1447 in the
cute_dsl_fused_moe_nvfp4 compatibility entry point before forwarding; do the
same at lines 1487-1514 in cute_dsl_fused_moe_mxfp8_mxfp4, and emit it when
constructing CuteDslMxfp8Mxfp4MoEWrapper at lines 1560-1576. Use the existing
warnings mechanism and preserve the forwarding and construction behavior.
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Fix all unresolved CodeRabbit comments on this PR:
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docs/api/fused_moe.rstflashinfer/__init__.pyflashinfer/fused_moe/__init__.pyflashinfer/fused_moe/cute_dsl/__init__.pyflashinfer/fused_moe/cute_dsl/fused_moe.pyflashinfer/trace/templates/moe.pyscripts/pr_checks/check_api_docs.pytests/moe/test_cute_dsl_fused_moe.pytests/moe/test_unified_moe.py
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- tests/moe/test_unified_moe.py
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This PR will be followed by low latency optimizations to the MoE kernel that can handle mixed inputs |
PR Review ScreeningCI verdict: ✅ auto-run ok Security
Packaging
C1.2 signatures (before → after)
Presentation
Implementation
Notes for the maintainer
Generated by flashinfer-pr-screen · rubric: docs/code_review_guidance.md · not a code review · AI screening can make mistakes — a maintainer's judgment supersedes this report. |
| @@ -207,7 +206,6 @@ | |||
| "PrequantizedMoEWeights", | |||
| "UnquantizedMoEWeights", | |||
| "Sm100_Mxfp8_Mxfp8_Bf16_Cutedsl_MegaMoeConfig", | |||
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This is the one rename in the PR that lands as a hard break. Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig was in __all__ here (88 entries) and in moe_ep/modes/__init__.py (13 entries), so from flashinfer.moe_ep import Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig now raises ImportError rather than warning — while CuteDslNvfp4Runner, cute_dsl_fused_moe_nvfp4, cute_dsl_fused_moe_mxfp8_mxfp4, CuteDslMxfp8Mxfp4MoEWrapper, prepare_cute_dsl_nvfp4_weights and even quant_mode="nvfp4" all kept a DeprecationWarning shim. Was the asymmetry deliberate?
Restoring the __all__ entry, for compatibility:
| "Sm100_Mxfp8_Mxfp8_Bf16_Cutedsl_MegaMoeConfig", | |
| "Sm100_Mxfp8_Mxfp8_Bf16_Cutedsl_MegaMoeConfig", | |
| "Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig", |
backed by a module-level __getattr__, matching the pattern this PR already uses at flashinfer/fused_moe/runners.py:4032 (PEP 562 lets __all__ name an attribute served this way, so import * keeps working):
def __getattr__(name: str):
# Retained for compatibility: exported in __all__ prior to the CuTe-DSL
# MoE consolidation. Superseded by FusedMoeKernelConfig.
if name == "Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig":
import warnings
warnings.warn(
"Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig is deprecated; use "
"FusedMoeKernelConfig(moe_config=..., mxfp8_dispatch=...) instead.",
DeprecationWarning,
stacklevel=2,
)
return FusedMoeKernelConfig
raise AttributeError(f"module {__name__!r} has no attribute {name!r}")FusedMoeKernelConfig is already imported at line 138 and warnings is imported locally elsewhere in this file (line 352), so no new top-level imports are needed.
One caveat worth deciding on explicitly: this is import-compatible, not call-compatible. The old dataclass defaulted every field (kernel_name, enable_pdl, tactic, mxfp8_dispatch), so Sm100_Mxfp8_Mxfp4_Bf16_Cutedsl_SplitConfig() was valid; FusedMoeKernelConfig requires moe_config. Callers therefore get a DeprecationWarning naming the replacement instead of a bare ImportError, but still have to supply a moe_config. If you'd rather not imply more compatibility than exists, a __getattr__ that raises with the same migration text is the honest alternative — either beats the current silent removal.
The likeliest external importer is the vLLM integration described in docs/design_docs/vllm_moe_ep_integration.md; docs/design_docs/moe_ep_architecture.md also documents this config by name and would need updating either way.
Suggested via flashinfer-pr-screen follow-up · AI-assisted — a maintainer's judgment supersedes this.
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approved and discussed in a review meeting @PetersonGuo lmk if you will make any more changes. i'll start the CI for now |
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/bot run tests/moe tests/moe_ep |
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[FAILED] Pipeline #65518514 — 14/16 executed test jobs passed Compared with nightly #65430604. Unit Tests
✅ Pass · 🟡 Old failure · ❌ New failure · ⏱ Test timeout · Multi-GPU and Multi-Node Tests — 6/6 passed
Failure detailsTimeouts, infrastructure, or incomplete jobs
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Resolves two conflicts introduced by flashinfer-ai#4793 ("Unify MoE CuTe DSL dispatch to be dtype agnostic") and flashinfer-ai#4646. flashinfer/fused_moe/runners.py flashinfer-ai#4793 replaced CuteDslNvfp4Runner with the dtype-agnostic CuteDslRunner (NVFP4 + MXFP4/W4A8 + W4A16) and added three W4A8 checks to _check_support(). Kept both sides: upstream's checks stay, and _assert_rubin_cute_dsl_available() is called after them. Because the probe now lives on a runner serving three quant variants rather than on the NVFP4-only class, it is explicitly scoped to NVFP4 to preserve its original blast radius. MXFP4/W4A8 is already declined on SM107 by upstream's new check, and W4A16 gates itself through require_cute_dsl_arch(); widening the rubin_helpers probe to those paths would be a behaviour change this branch never intended. tests/moe/test_cute_dsl_fused_moe.py flashinfer-ai#4793 renamed cute_dsl_fused_moe_nvfp4 -> cute_dsl_fused_moe at this call site. Kept our SM107 SiTU skip and took upstream's new name. The three remaining cute_dsl_fused_moe_nvfp4 references are upstream's own deprecation test and are unchanged. No functional change to either side's intent.
…on main) (#4903) ## 📌 Description `tests/moe/test_unified_moe_activation_matrix.py::test_documented_activation_matrix_matches_runner_registry` is failing on `main`, which blocks CI for **every open PR**: ``` AssertionError: docs/design_docs/flashinfer_moe_api.md is stale; run: python scripts/generate_moe_activation_matrix.py --write ``` This is a **semantic merge conflict**, not a defect in any single PR. #4805 added the generator, its check test, and a matrix block rendered from `_BACKEND_RUNNERS` as it stood on that PR's base. Two changes landed on `main` in between, and neither could have known to re-render the block: | Change | Effect on the matrix | |---|---| | #4793 (`f7d4b167`) | renamed `CuteDslRunner.backend_key` `cute_dsl_nvfp4` → `cute_dsl` and added `QuantVariant.MXFP4` to its supported variants | | #4646 (`0cbace05`) | registered `CuTileBf16Runner` / `CuTileNvfp4Runner` in `_BACKEND_RUNNERS` | Each PR was green on its own base; the merged tree is what is stale. Because the check compares the committed block against the live registry, it has been red for everyone since #4805 merged. ## 🔍 Change Only the generated block changes — this commit is the mechanical output of the documented regeneration command: ``` python scripts/generate_moe_activation_matrix.py --write ``` - adds `cutile_bf16` (`BF16`) and `cutile_nvfp4` (`NVFP4`), both `SwiGLU`, `ReLU2` - replaces the two `cute_dsl_nvfp4` rows with three `cute_dsl` rows (`MXFP4`, `NVFP4`, `W4A16`) No source, test, or prose changes. ## 🧪 Testing The authoritative check is `test_documented_activation_matrix_matches_runner_registry`, which runs in this PR's own CI. ## 🔗 Related Surfaced while triaging CI on #4387, whose H100 job ran the full suite with 221,273 passing and this as the sole failure. <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **Documentation** * Updated the MoE activation matrix table to document MXFP4, NVFP4, and W4A16 support across additional activation functions. * Added documented BF16 and NVFP4 configuration entries for CuTile implementations. <!-- end of auto-generated comment: release notes by coderabbit.ai --> Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
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📌 Description
Consolidates the CuTe-DSL fused MoE implementation behind dtype-agnostic APIs
Overall diff versus main: approximately 1,800 net lines removed.
🔍 Related Issues
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Summary by CodeRabbit
New Features
API Updates
cute_dsl_fused_moeandCuteDslRunnerAPIs.Documentation