This repository has been archived by the owner on Feb 25, 2025. It is now read-only.
[Impeller] Fix a race between SwapchainImplVK::Present and WaitForFence #49777
Conversation
This file contains 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
|
It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact "@test-exemption-reviewer" in the #hackers channel in Chat (don't just cc them here, they won't see it! Use Discord!). If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix? Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. |
chinmaygarde
approved these changes
Jan 13, 2024
The previous implementation used an fml::CountDownLatch to synchronize between FrameSynchronizer::WaitForFence and the task queued by SwapchainImplVK::Present. fml::CountDownLatch:Wait always waits, even if the count is already zero. So the raster thread would deadlock if the present task signals the latch before FrameSynchronizer::WaitForFence enters the wait. This PR instead uses a semaphore that is set each time SwapchainImplVK::Present is called. FrameSynchronizer::WaitForFence will check the semaphore to determine whether a present task is pending and if so wait for its completion.
jason-simmons
force-pushed
the
iplr_vk_present_latch_race
branch
from
2f80d6b to
13e1e3f
Compare
|
test-exempt: not really testable |
|
(bonus points for figuring out a way to reliably trigger the deadlock though!) |
|
I had originally noticed this while running the Lottie animation example from flutter/flutter#139796 with Impeller/Vulkan. On a Pixel 6a the app typically hangs within a few minutes. With this PR I have not seen the hang. |
jason-simmons
added
the
autosubmit
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/flutter
that referenced
this pull request
Jan 16, 2024
auto-submit bot
pushed a commit
to flutter/flutter
that referenced
this pull request
Jan 17, 2024
…141651) flutter/engine@d4b6b7e...021a5ff 2024-01-16 [email protected] [web] Leave blob URLs untouched in TT policy. (flutter/engine#49782) 2024-01-16 [email protected] [Impeller] Fix a race between SwapchainImplVK::Present and WaitForFence (flutter/engine#49777) 2024-01-16 [email protected] Reland "[Windows] Move to FlutterCompositor for rendering" (flutter/engine#49726) 2024-01-16 [email protected] [Impeller] Add an API for sampling strictly within the bounds of the source rect in DrawImageRect (flutter/engine#49696) 2024-01-16 [email protected] [Impeller] Encode directly to command buffer for Vulkan. (flutter/engine#49780) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC [email protected],[email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: 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
auto-submit bot
added a commit
to flutter/flutter
that referenced
this pull request
Jan 17, 2024
…isions)" (#141659) Reverts #141651 Initiated by: jonahwilliams This change reverts the following previous change: Original Description: flutter/engine@d4b6b7e...021a5ff 2024-01-16 [email protected] [web] Leave blob URLs untouched in TT policy. (flutter/engine#49782) 2024-01-16 [email protected] [Impeller] Fix a race between SwapchainImplVK::Present and WaitForFence (flutter/engine#49777) 2024-01-16 [email protected] Reland "[Windows] Move to FlutterCompositor for rendering" (flutter/engine#49726) 2024-01-16 [email protected] [Impeller] Add an API for sampling strictly within the bounds of the source rect in DrawImageRect (flutter/engine#49696) 2024-01-16 [email protected] [Impeller] Encode directly to command buffer for Vulkan. (flutter/engine#49780) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC [email protected],[email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: 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
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/flutter
that referenced
this pull request
Jan 17, 2024
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/flutter
that referenced
this pull request
Jan 17, 2024
auto-submit bot
pushed a commit
to flutter/flutter
that referenced
this pull request
Jan 17, 2024
…141664) flutter/engine@d4b6b7e...1382ff7 2024-01-16 [email protected] Remove iOS 12 availability checks (flutter/engine#49771) 2024-01-16 [email protected] [Impeller] generate mipmaps for imagefilters (flutter/engine#49794) 2024-01-16 [email protected] [web] Leave blob URLs untouched in TT policy. (flutter/engine#49782) 2024-01-16 [email protected] [Impeller] Fix a race between SwapchainImplVK::Present and WaitForFence (flutter/engine#49777) 2024-01-16 [email protected] Reland "[Windows] Move to FlutterCompositor for rendering" (flutter/engine#49726) 2024-01-16 [email protected] [Impeller] Add an API for sampling strictly within the bounds of the source rect in DrawImageRect (flutter/engine#49696) 2024-01-16 [email protected] [Impeller] Encode directly to command buffer for Vulkan. (flutter/engine#49780) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC [email protected],[email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: 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
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
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.
The previous implementation used an fml::CountDownLatch to synchronize between FrameSynchronizer::WaitForFence and the task queued by SwapchainImplVK::Present.
fml::CountDownLatch:Wait always waits, even if the count is already zero. So the raster thread would deadlock if the present task signals the latch before FrameSynchronizer::WaitForFence enters the wait.
This PR instead uses a semaphore that is set each time SwapchainImplVK::Present is called. FrameSynchronizer::WaitForFence will check the semaphore to determine whether a present task is pending and if so wait for its completion.