Do not yield in CoroutineScheduler during transition to the idle stat… #884
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
…e, introduce system properties to tune this behaviour. Rationale: Thread.yield has a significant CPU cost (especially relatively to spins) and provides no significant benefits compared with exponential parking. Thus yields burn a lot of CPU due to JVM upcall + syscall, providing benefits neither for liveness property (as CPU is mostly busy with doing these calls) nor for latencies. Initial benchmarking shows significant CPU usage reduction (200-300%) in low-to-average load benchmarks with no degradation on target affinity benchmarks. Partially addresses #840
|
Note that change does not completely fix #840, a transition to the idle state still can be significantly improved |
|
Hi,
Sorry to disturb, but how can a reduction be more than 100%? |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
…e, introduce system properties to tune this behaviour.
Rationale:
Thread.yield has a significant CPU cost (especially relatively to spins) and provides no significant benefits compared with exponential parking.
Thus yields burn a lot of CPU due to JVM upcall + syscall, providing benefits neither for liveness property (as CPU is mostly busy with doing these calls) nor for latencies. Initial benchmarking shows significant CPU usage reduction (200-300%) in low-to-average load benchmarks with no degradation on target affinity benchmarks.
Partially addresses #840