Revert "IO: switch Win32 pipes to PIPE_WAIT and use a sentinel byte"#891
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compnerd
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Aug 8, 2025
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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