[Quantization] Remove the dead ocp_mx_scheme branch from moe_kernel_quantize_input - #52603
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AndreasKaratzas merged 1 commit intoAug 18, 2026
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…l_quantize_input`
`moe_kernel_quantize_input` carries an `ocp_mx_scheme` parameter and a
leading branch that short-circuits `*_a_fp8` schemes into
`_fp8_quantize_dequantize`. Nothing reaches it: of the 26 call sites in
the tree, none supplies `ocp_mx_scheme=`, the maximum positional arity at
any of them is 5 against a parameter at positional index 6, and there is
no `**kwargs` splat, aliased import, `functools.partial` or `getattr`
reference anywhere.
The one arm with behavior was `.endswith("a_fp8")`, and the only
reachable a_fp8 scheme is `w_mxfp4_a_fp8` -- `w_mxfp6_e3m2_a_fp8` and
`w_mxfp6_e2m3_a_fp8` raise `NotImplementedError` earlier in
`QuarkOCP_MX_MoEMethod.get_fused_moe_quant_config`. For that scheme the
emulation experts set `quantization_emulation = True` and
`quant_dtype = current_platform.fp8_dtype()`, so the surviving dispatch
reaches the identical `_fp8_quantize_dequantize(A, A_scale)`. The other
two arms were a bare `pass` and a comment.
Remove both, per the in-code TODO and @fxmarty-amd's review on vllm-project#43983:
"`moe_kernel_quantize_input` should rely solely on `quant_dtype` now".
`FusedMoEQuantConfig.ocp_mx_scheme` and its other consumers
(`OCP_MXQuantizationEmulationTritonExperts`, the `fused_batched_moe`
NYI asserts, the deprecation guard in `fused_experts_impl`) are
untouched.
Signed-off-by: xuebwang-amd <xuebwang@amd.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
xuebwang-amd
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August 17, 2026 10:44
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xuebwang-amd
changed the title
ocp_mx_scheme branch from `moe_kerne…
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LGTM thanks a lot for the cleanup!
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✅ Triggered Buildkite CI #84394 for commit |
AndreasKaratzas
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Aug 18, 2026
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…uantize_input (vllm-project#52603) Signed-off-by: xuebwang-amd <xuebwang@amd.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com> Signed-off-by: Wenhua Cheng <wenhua.cheng@intel.com>
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…uantize_input (vllm-project#52603) Signed-off-by: xuebwang-amd <xuebwang@amd.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com> Signed-off-by: Zhu, Zufang <zufang.zhu@intel.com>
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…uantize_input (vllm-project#52603) Signed-off-by: xuebwang-amd <xuebwang@amd.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
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Purpose
Shortly, remove dead code.
moe_kernel_quantize_input()invllm/model_executor/layers/fused_moe/utils.pycarries anocp_mx_scheme: str | None = Noneparameter and opens its body with a block that short-circuits*_a_fp8OCP MX schemes into_fp8_quantize_dequantizebefore the normalquant_dtypedispatch ever runs. Nothing reaches that block. This PR removes the parameter and the block.This is the follow-up @fxmarty-amd asked for when introduced the
quantization_emulationpath that superseded the block, in #46142 (e368415daa):This is the left TODO:
and reconfirmed the ask in review on #43983 (review 4904664996), linking
utils.py#L288-L301— exactly the lines removed here.Why deleting it changes no behavior
The only arm with behavior was
.endswith("a_fp8"), and the only reachable a_fp8 scheme isw_mxfp4_a_fp8—w_mxfp6_e3m2_a_fp8andw_mxfp6_e2m3_a_fp8, both raiseNotImplementedErrorearlier, inQuarkOCP_MX_MoEMethod.get_fused_moe_quant_config.For
w_mxfp4_a_fp8the two paths are identical:ocp_mx_scheme.endswith("a_fp8")quant_dtype == current_platform.fp8_dtype()andquantization_emulationreturn _fp8_quantize_dequantize(A, A_scale)return _fp8_quantize_dequantize(A, A_scale)_fp8_quantize_dequantizetakes onlyAandA_scale, so nothing else was being bypassed.OCP_MXQuantizationEmulationTritonExperts.__init__sets both inputs (quantization_emulation = True,_quant_dtype = current_platform.fp8_dtype()), andTritonExperts.applyforwards them.Test Plan
Unit test
End-to-end test
Same as what tested in #43983
Test Result
Coming soon.
Essential Elements of an Effective PR Description Checklist
supported_models.mdandexamplesfor a new model.