[win32] Runloop should use high resolution timer and avoid deadlock #176023
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This comment was marked as outdated.
This comment was marked as outdated.
github-actions
bot
added
engine
knopp
force-pushed
the
fix_win_events
branch
2 times, most recently
from
7297da4 to
31d3582
Compare
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Code Review
This pull request replaces the legacy SetTimer/WM_TIMER mechanism with a modern threadpool timer to achieve higher resolution and prevent deadlocks in the event loop. The overall approach is sound, but I've identified a critical issue with the timer configuration that would cause it to fire periodically instead of as a one-shot timer. Additionally, there are a couple of missing null checks for the new timer handle that could lead to crashes if timer creation fails. I've provided suggestions to fix these issues and a minor one to improve code robustness by initializing member variables.
Comment on lines
+46
to
60
| CloseThreadpoolTimer(timer_); | ||
|
|
||
| if (window_handle_) { |
Contributor
There was a problem hiding this comment.
To prevent a crash if timer_ is nullptr (for example, if its creation failed in the constructor), this block of timer cleanup code should be wrapped in a null check.
if (timer_) {
SetThreadpoolTimer(timer_, nullptr, 0, 0);
WaitForThreadpoolTimerCallbacks(timer_, TRUE);
CloseThreadpoolTimer(timer_);
}
Member
Author
There was a problem hiding this comment.
Don't think this makes much sense to do. Failing to create the timer would pretty much render the application useless and will likely crash way earlier when trying to arm the timer.
knopp
force-pushed
the
fix_win_events
branch
from
31d3582 to
3cf0fdd
Compare
knopp
changed the title
knopp
changed the title
mattkae
approved these changes
Sep 26, 2025
Contributor
mattkae
left a comment
mattkae
left a comment
There was a problem hiding this comment.
Feels smooth to me! I have some suggestions, but I'll let Loic be the final call
loic-sharma
approved these changes
Sep 26, 2025
Member
loic-sharma
left a comment
loic-sharma
left a comment
There was a problem hiding this comment.
Thanks for the fix! Great tests :)
Member
|
Does this improve #97334 by any chance? (I'm traveling and can't check myself) |
Member
Author
I have no idea really. The vsync waiter on windows needs some work I think. We have the period right, but not the initial offset (last time I checked). |
knopp
force-pushed
the
fix_win_events
branch
from
04e311c to
f1fcf01
Compare
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/packages
that referenced
this pull request
Oct 1, 2025
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/packages
that referenced
this pull request
Oct 1, 2025
auto-submit bot
pushed a commit
to flutter/packages
that referenced
this pull request
Oct 1, 2025
…10160) Manual roll requested by [email protected] flutter/flutter@c9608e2...7811e89 2025-10-01 [email protected] Migrate to `WidgetStateTextStyle` (flutter/flutter#176330) 2025-10-01 [email protected] Migrate to `WidgetStateOutlinedBorder` (flutter/flutter#176270) 2025-10-01 [email protected] [win32] Runloop should use high resolution timer and avoid deadlock (flutter/flutter#176023) 2025-10-01 [email protected] Roll Packages from 287739d to 321a584 (3 revisions) (flutter/flutter#176357) 2025-10-01 [email protected] Add SwiftUI support for UIScene migration (flutter/flutter#176230) 2025-10-01 [email protected] Roll Skia from ecaff95f51aa to c44a36470d07 (4 revisions) (flutter/flutter#176336) 2025-10-01 [email protected] [native assets] Enable build hooks and code assets on stable (flutter/flutter#176285) 2025-10-01 [email protected] [native assets] Roll dependencies (flutter/flutter#176287) 2025-10-01 [email protected] Roll Dart SDK from 527333cfe4cf to 8ffec1435cf3 (1 revision) (flutter/flutter#176334) 2025-10-01 [email protected] Roll Skia from 6998b06397c5 to ecaff95f51aa (1 revision) (flutter/flutter#176333) 2025-10-01 [email protected] Update description in _LastFinderMixin to properly describe finding last (flutter/flutter#174232) 2025-10-01 [email protected] Roll Skia from b242cc09488d to 6998b06397c5 (2 revisions) (flutter/flutter#176331) 2025-10-01 [email protected] Roll Dart SDK from af31d2637b6b to 527333cfe4cf (17 revisions) (flutter/flutter#176325) 2025-10-01 [email protected] Stop using deprecated analyzer 7.x.y APIs. (flutter/flutter#176242) 2025-10-01 [email protected] Fix docs referencing deprecated radio properties (flutter/flutter#176244) 2025-09-30 [email protected] Roll Skia from bb3b6bd4be0d to b242cc09488d (22 revisions) (flutter/flutter#176320) 2025-09-30 [email protected] Roll Fuchsia Linux SDK from rcOl0yxJb4znJ903Y... to 1Ai6VL4vb_GdGnWhg... (flutter/flutter#176315) 2025-09-30 [email protected] Adds dart ui API for setting application level locale (flutter/flutter#175100) 2025-09-30 [email protected] replace `onPop` usage with `onPopWithResult` in `navigation_bar.2.dart ` (flutter/flutter#174841) 2025-09-30 [email protected] [ Widget Preview ] Forward Widget Inspector navigation events via DTD (flutter/flutter#176218) 2025-09-30 [email protected] Add verbose logs to module_uiscene_test_ios (flutter/flutter#176306) 2025-09-30 [email protected] Web semantics: Fix email field selection/cursor by using type="text" + inputmode="email" (flutter/flutter#175876) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
|
Will this fix this issue aswell? |
okorohelijah
pushed a commit
to okorohelijah/flutter
that referenced
this pull request
Oct 7, 2025
…lutter#176023) Replaces `SetTimer`/`WM_TIMER` with a threadpool timer, which doesn't suffer from 16ms granularity and changes the waking up mechanism to give the run loop chance to process input messages before processing flutter tasks. - Fixes flutter#173843 - Fixes flutter#175135 *If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].* ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
3 tasks
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/packages
that referenced
this pull request
Nov 12, 2025
reidbaker
pushed a commit
to AbdeMohlbi/flutter
that referenced
this pull request
Dec 10, 2025
…lutter#176023) Replaces `SetTimer`/`WM_TIMER` with a threadpool timer, which doesn't suffer from 16ms granularity and changes the waking up mechanism to give the run loop chance to process input messages before processing flutter tasks. - Fixes flutter#173843 - Fixes flutter#175135 *If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].* ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Replaces
SetTimer/WM_TIMERwith a threadpool timer, which doesn't suffer from 16ms granularity and changes the waking up mechanism to give the run loop chance to process input messages before processing flutter tasks.If you had to change anything in the flutter/tests repo, include a link to the migration guide as per the breaking change policy.
Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.
Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the
gemini-code-assistbot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.