gh-140795: fetch thread state once on fast path for critical sections #141406
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colesbury
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Nov 13, 2025
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How much of a difference does this make to |
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It is ~5% faster on macOS with this change. |
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Currently on the fastpath for critical section where the objects are not locked, the thread state is fetched twice once while acquiring it and once while releasing it. This PR optimizes it to fetch it once and store it (in a temp variable on stack) so that on the fastpath thread state is fetched once.
This should help performance in shared modules such as
sslwhere thread state access is slower because of extra function call to_PyThreadState_GetCurrent.