[ROCm] Disable AITER allreduce fusion

[jpvillam-amd]

Subset of #41816

Singular fix to disable aiter all reduce fusion pass

Purpose

RocmAiterAllReduceFusionPass is currently causing accuracy issues, disable until its fixed

Test Plan

Tested with DeepSeek FP4 and Llama

Test Result

Recovered accuracy after the change

Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

[claude]

Claude Code Review

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[gemini-code-assist]

Code Review

This pull request refactors the PassManager to simplify the inclusion of the AllReduceFusionPass. Feedback indicates that AllReduceFusionPass is NVIDIA-specific and its usage should be guarded to prevent issues on ROCm platforms. Additionally, the reviewer suggested removing the now-unused RocmAiterAllReduceFusionPass import.

[gemini-code-assist]

The AllReduceFusionPass is an NVIDIA-specific optimization that relies on FlashInfer. Including rocm_aiter_ops.is_enabled() in this import condition is misleading and unnecessary if the usage is properly guarded. It should remain restricted to CUDA platforms to avoid confusing initialization warnings on ROCm. Additionally, since RocmAiterAllReduceFusionPass is no longer used in this file, its import (lines 24-27) should also be removed.

Suggested change

	if rocm_aiter_ops.is_enabled() or current_platform.is_cuda():
	from .fusion.allreduce_rms_fusion import AllReduceFusionPass
	if current_platform.is_cuda():
	from .fusion.allreduce_rms_fusion import AllReduceFusionPass

[mergify]

Hi @jpvillam-amd, the pre-commit checks have failed. Please run:

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Tip

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[tjtanaa]

@jpvillam-amd @gshtras may I know what is the reason to disable all reduce fusion when we can control through python argument by setting --compilation_config.pass_config.fuse_allreduce_rms=false

[tjtanaa]

And it is preferred to not remove the path completely as it was working with older aiter version, and we should should disable else where and add a TODO to fix it.

[tjtanaa]

@jpvillam-amd which aiter version are you using? During the integration of the kernel, the rmsnorm all reduce fusion pass doesn't seem to be enabled by default. Can you share your vllm serve commands?

If you are using -O2 / -O3 then we should update the list

https://github.com/vllm-project/vllm/blob/d4b00484040c9a0bbd4ee2d55983df7a50ab1fd3/vllm/config/vllm.py#L217-238

https://github.com/vllm-project/vllm/blob/d4b00484040c9a0bbd4ee2d55983df7a50ab1fd3/vllm/config/vllm.py#L239-258
to not use it unless user explicitly set the rmsnorm all reduce fusion

[akii96]

Hi! I made a new PR which does not require disabling the fusion if someone wants to check it (it was a simple one liner fix) Check #41972

[gshtras]

Closing for #41972