add the fa4 mm backend and varlen func#13539
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Fridge003 merged 6 commits intosgl-project:mainfrom Jan 23, 2026
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Please format the comments in description. I'll follow up. |
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/tag-and-rerun-ci again |
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/tag-and-rerun-ci |
JustinTong0323
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Jan 14, 2026
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Hi @vincentzed Please resolve the conflicts |
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@b8zhong @vincentzed Please take a look at this failure https://github.com/sgl-project/sglang/actions/runs/21097596083/job/60719449425?pr=13539 |
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@Fridge003 Thanks, yes, it's from SM120 device not supporting FA4 yet. should be fixed in c9591ae |
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FA4TritonThey are similar at low bs. |
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Jan 21, 2026
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Jan 21, 2026
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Feb 14, 2026
Signed-off-by: vincentzed <207368749+vincentzed@users.noreply.github.com> Co-authored-by: Brayden Zhong <b8zhong@uwaterloo.ca>
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It's the same acc, but there is not a major speedup, MMMU benchmark is not reliable re: time it take to finish.
Before
After
Benchmarks
Launch LLM:
python -m sglang.launch_server --model-path Qwen/Qwen3-VL-8B-Instruct --port 30000 --mm-attention-backend fa4 --trust-remote-code
Before
After
Motivation
Modifications
Accuracy Tests
Benchmarking and Profiling
Checklist