fix: remove pr_empty flag in ex_cpu queue which was causing lost wakeups#175
Merged
fix: remove pr_empty flag in ex_cpu queue which was causing lost wakeups#175
Conversation
Contributor
Just out of curiosity: how soon? Will it be wsq from TaskFlow or something new from scratch? |
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
[backported to v1.3]
pr_empty was added in v1.3 as an optimization for the case where a thread is only pulling data from another thread and not spawning any tasks in its own queue. However, this could lead to lost wakeups in lightly loaded scenarios if this thread raced with another thread and both threads failed to dequeue the item (which can happen during normal operation of the queue); it would then mark its own queue as "empty" and then not check it again.
Reverting the pr_empty flag is the simplest solution for now, as I'm planning to switch to a more efficient Chase-Lev queue in the future.