optimize: remove unnecessary DelayCancellation stage from RestartFlow#2975
Open
He-Pin wants to merge 1 commit into
Open
optimize: remove unnecessary DelayCancellation stage from RestartFlow#2975He-Pin wants to merge 1 commit into
He-Pin wants to merge 1 commit into
Conversation
Motivation: RestartFlow had ~3x less throughput than RetryFlow due to an unnecessary DelayCancellation stage in the inner flow graph. This stage added per-element overhead (extra grab/push/pull operations) even when not needed. Modification: Only apply the DelayCancellation stage when onlyOnFailures mode is enabled. For the common RestartFlow.withBackoff case, the stage is removed. Result: Significantly improved throughput for RestartFlow.withBackoff. The onFailuresWithBackoff path retains the DelayCancellation stage for correctness (race condition fix for #23909). Tests: - All 38 existing RestartSpec tests pass Refs: akka/akka-core#31225
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Motivation
RestartFlow had ~3x less throughput than RetryFlow due to an unnecessary
DelayCancellationstage in the inner flow graph. This stage added per-element overhead (extragrab/push/pulloperations) even when not needed.See: akka/akka-core#31225
Modification
Only apply the
DelayCancellationstage whenonlyOnFailuresmode is enabled. For the commonRestartFlow.withBackoffcase, the stage is removed, eliminating the per-element overhead.The
DelayCancellationstage was a workaround for a race condition (see #23909) where cancellation could arrive before a failure signal inonlyOnFailuresmode. For the non-onlyOnFailurescase, theSubSourceOutlet.onDownstreamFinishhandler already schedules a restart, so the delay is unnecessary.Result
Significantly improved throughput for
RestartFlow.withBackoff. TheonFailuresWithBackoffpath retains theDelayCancellationstage for correctness.Tests
RestartSpectests passRefs
Refs akka/akka-core#31225