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[Bugfix] Fix Qwen3-VL-MoE weight loading for EP - #25300

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vllm-bot merged 2 commits into
vllm-project:mainfrom
ywang96:fix-qwen3-vl-ep
Sep 20, 2025
Merged

vllm-bot merged 2 commits into
vllm-project:mainfrom
ywang96:fix-qwen3-vl-ep

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@ywang96

@ywang96 ywang96 commented Sep 20, 2025 •

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Purpose

Previously self.load_fused_expert_weights check is too strict and will prevent server from launching with --enable-expert-parallel. This PR fixes it.

Test Plan

The MMMU from server launched with/without --enable-expert-parallel matched.

Test Result


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.
  • (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

Signed-off-by: Roger Wang <hey@rogerw.io>
@ywang96
ywang96 requested a review from sighingnow as a code owner September 20, 2025 03:52
@mergify mergify Bot added the qwen Related to Qwen models label Sep 20, 2025

@gemini-code-assist gemini-code-assist Bot left a comment

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Code Review

This pull request fixes a bug in the weight loading logic for Qwen3-VL-MoE models when using expert parallelism (EP). The previous implementation of load_fused_expert_weights was too strict, causing weight loading to fail if any expert was not present on a given rank. The change correctly modifies the logic to consider the loading successful if at least one expert's weights are loaded on the rank, which is the expected behavior for expert parallelism. The changes are correct and effectively address the issue. There is also a minor whitespace change to add a newline at the end of a file.

@ywang96
ywang96 requested a review from Isotr0py September 20, 2025 03:55
@Isotr0py
Isotr0py enabled auto-merge (squash) September 20, 2025 04:05
@github-actions github-actions Bot added the ready ONLY add when PR is ready to merge/full CI is needed label Sep 20, 2025
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vllm-bot merged commit be874c0 into vllm-project:main Sep 20, 2025
@ywang96 ywang96 mentioned this pull request Sep 20, 2025
7 of 12 tasks
charlifu pushed a commit to ROCm/vllm that referenced this pull request Sep 25, 2025
Signed-off-by: Roger Wang <hey@rogerw.io>
Signed-off-by: charlifu <charlifu@amd.com>
yewentao256 pushed a commit that referenced this pull request Oct 3, 2025
Signed-off-by: Roger Wang <hey@rogerw.io>
Signed-off-by: yewentao256 <zhyanwentao@126.com>
choprahetarth pushed a commit to Tandemn-Labs/vllm that referenced this pull request Oct 11, 2025
ptrdlr14 pushed a commit to ptrdlr14/vllm that referenced this pull request Oct 20, 2025
mystous pushed a commit to mystous/vllm_hybrid that referenced this pull request May 10, 2026
my-other-github-account pushed a commit to my-other-github-account/vllm that referenced this pull request May 15, 2026
my-other-github-account pushed a commit to my-other-github-account/vllm that referenced this pull request May 15, 2026
Signed-off-by: Roger Wang <hey@rogerw.io>
Signed-off-by: yewentao256 <zhyanwentao@126.com>
0826joyce pushed a commit to 0826joyce/vllm-serving-optimization that referenced this pull request May 19, 2026
plasticchris pushed a commit to plasticchris/vllm that referenced this pull request Jul 20, 2026
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3 participants