CommandQueueMT: Fix sync command awaiters missing the chance
#91725
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I've tested this repeatedly now and it does appear to solve the issue on all platforms. |
akien-mga
approved these changes
May 9, 2024
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Thanks! |
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The recent new implementation of waiting for a sync command to have run used
!=to compare the sync head with the tail. The problem was that an awaiter could be notified due to thread scheduling at any point after the event. That means that, say, an awaiter of sync command3could be awaken by the time sync command6has already run.The fix is not as easy as using
<instead because, as stated by a comment in the code, if wraparound ever happened, sync would break. Therefore, this PR adds some logic to reset the counters at the earliest opportunity so they never reach high values.Also, the mutex is unlocked to give an opportunity to awaiters of realizing the wait is over and go on.
As a bonus, the leftover
SYNC_SEMAPHORESconstant is removed.Fixes #91520.