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feat: add forward timeout#17831

Merged
BBuf merged 1 commit intosgl-project:mainfrom
zhooooong:zhong/add_forward_timeout
Jan 30, 2026
Merged

feat: add forward timeout#17831
BBuf merged 1 commit intosgl-project:mainfrom
zhooooong:zhong/add_forward_timeout

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@zhooooong zhooooong commented Jan 27, 2026

Motivation

Introduce a timeout for requests in the forward batch.

Modifications

Introduce a new environment variable SGLANG_FORWARD_TIMEOUT_MS. In the scheduler, abort requests that have exceeded the forward timeout before the next decode step.

Accuracy Tests

server cmd:

export SGLANG_FORWARD_TIMEOUT_MS=1  # 1ms for test
python3 -m sglang.launch_server --model $model_path --skip-server-warmup

Then, send a few requests casually. Subsequently, the requests encountered the error, as expected:

{"object":"error","message":"Forward timeout.","type":"HTTPStatus.SERVICE_UNAVAILABLE","param":null,"code":503}

Benchmarking and Profiling

Checklist

Review Process

  1. Ping Merge Oncalls to start the PR flow. See the PR Merge Process.
  2. Get approvals from CODEOWNERS and other reviewers.
  3. Trigger CI tests with comments or contact authorized users to do so.
    • /tag-run-ci-label, /rerun-failed-ci, /tag-and-rerun-ci
  4. After green CI and required approvals, ask Merge Oncalls to merge.

@github-actions github-actions Bot added the documentation Improvements or additions to documentation label Jan 27, 2026
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gemini-code-assist Bot commented Jan 27, 2026

Summary of Changes

Hello @zhooooong, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the SGLang server's robustness by integrating a configurable timeout mechanism for requests during their forward processing. This feature prevents requests from consuming excessive resources or hanging indefinitely, thereby improving the overall stability and responsiveness of the server by gracefully handling long-running or stuck operations.

Highlights

  • New Environment Variable: Introduced SGLANG_FORWARD_TIMEOUT_MS to configure a timeout for requests within the forward batch.
  • Request Abort Mechanism: Implemented logic in the scheduler to abort requests that exceed the configured SGLANG_FORWARD_TIMEOUT_MS during both prefill and decode phases.
  • Documentation Update: The new environment variable SGLANG_FORWARD_TIMEOUT_MS has been added to the official documentation.
  • Unit Test Coverage: A new unit test has been added to verify the functionality of the forward timeout, ensuring requests are correctly aborted when the timeout is exceeded.

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Code Review

The pull request introduces a new environment variable SGLANG_FORWARD_TIMEOUT_MS to control the timeout for requests in the forward batch. The implementation correctly integrates this timeout into both prefill and decode stages of the scheduler, aborting requests that exceed the configured duration. A dedicated unit test has been added to verify the functionality, ensuring that requests time out as expected. The documentation has also been updated to reflect the new environment variable. The changes are well-implemented and thoroughly tested.

@BBuf
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BBuf commented Jan 28, 2026

/tag-and-rerun-ci

@BBuf BBuf merged commit 2b3408f into sgl-project:main Jan 30, 2026
198 of 221 checks passed
charlesHsuGG pushed a commit to charlesHsuGG/sglang that referenced this pull request Jan 30, 2026
@zhooooong
feat: add forward timeout (sgl-project#17831)
b855dd6 
Co-authored-by: qiuxuan.lzw <qiuxuan.lzw@alibaba-inc.com>
Chen-0210 pushed a commit to Chen-0210/sglang that referenced this pull request Jan 30, 2026
@zhooooong @Chen-0210
feat: add forward timeout (sgl-project#17831)
f2f396a 
Co-authored-by: qiuxuan.lzw <qiuxuan.lzw@alibaba-inc.com>
sfiisf pushed a commit to sfiisf/sglang that referenced this pull request Feb 5, 2026
@zhooooong @sfiisf
feat: add forward timeout (sgl-project#17831)
b978582 
Co-authored-by: qiuxuan.lzw <qiuxuan.lzw@alibaba-inc.com>
@hnyls2002 hnyls2002 mentioned this pull request Feb 13, 2026
Merged
Johnsonms pushed a commit to Johnsonms/sglang that referenced this pull request Feb 14, 2026
@zhooooong @Johnsonms
feat: add forward timeout (sgl-project#17831)
658e230 
Co-authored-by: qiuxuan.lzw <qiuxuan.lzw@alibaba-inc.com>
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@BBuf BBuf BBuf approved these changes

@merrymercy merrymercy Awaiting requested review from merrymercy merrymercy is a code owner

@Ying1123 Ying1123 Awaiting requested review from Ying1123 Ying1123 is a code owner

@hnyls2002 hnyls2002 Awaiting requested review from hnyls2002 hnyls2002 is a code owner

@xiezhq-hermann xiezhq-hermann Awaiting requested review from xiezhq-hermann xiezhq-hermann is a code owner

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