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[hist] Pause filling during snapshot - #23093
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Test Results 23 files 23 suites 3d 15h 3m 0s ⏱️ For more details on these failures, see this check. Results for commit 863501e. ♻️ This comment has been updated with latest results. |
pcanal
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pcanal
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pcanal
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FillAtomic is much faster than SnapshotAtomic, so in case of heavy contention it would starve the snapshot. By adding a new atomic flag FillAtomic can pause while a Snapshot is running. The successful double collect is still needed if a thread is already in FillAtomic. If SnapshotAtomic is not used, the performance impact of the added check is minimal / not measurable because fSnapshotInProgress is always false and already in the cache line of the RHistEngine.
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FillAtomicis much faster thanSnapshotAtomic, so in case of heavy contention it would starve the snapshot. By adding a new atomic flagFillAtomiccan pause while a Snapshot is running. The successful double collect is still needed if a thread is already in FillAtomic.If
SnapshotAtomicis not used, the performance impact of the added check is minimal / not measurable becausefSnapshotis always false and already in the cache line of theRHistEngine.