Revert "IO: switch Win32 pipes to PIPE_WAIT and use a sentinel byte"
#891
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
|
@swift-ci please test |
compnerd
approved these changes
Aug 8, 2025
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Outdated suggestions cannot be applied.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.
Explanation:
We found some issues with this approach (#882) and have since reverted the PR on
mainin #883, but it had already been cherry-picked torelease/6.2in #866.Scope:
libdispatch pipe communication on Windows platform
Issues:
#882
Original PRs:
#866 was the cherry-pick being reverted; #854 was the original PR
Risk:
This will re-introduce a regression in the Windows dispatch pipe handling code that causes a CPU thread to be fully saturated when pipe communication is used. (In other words, will reintroduce this issue #820). It was determined this was the lesser of two bugs compared to #882 which has correctness implications (compared to severe but manageable performance implications).
Testing:
This is a revert PR which removes the ToT change on the release/6.2 branch, so the state of the code will return to a previously tested state. As mentioned above, this will reintroduce the CPU-spinning bug.
Reviewers:
@compnerd