[
https://issues.apache.org/jira/browse/CASSANDRA-16072?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17186722#comment-17186722
]
Michael Semb Wever commented on CASSANDRA-16072:
------------------------------------------------
bq. CI runs took 2d and they all seem broken + I don't seem to be able to drill
down into the actual dtests runs themselves...
We've lost them from history already. I will re-run them.
bq. Thread C calls allocateBytes with totalSize == size_C and exit with the
return value size_B - 1 and and position == size_B + size_C -1
[~blerer], too true. A {{CLOSED}} constant doesn't make any sense against
{{getAndAdd(..)}}
Let me update…
> Reduce thread contention in CommitLogSegment and HintsBuffer by rewriting CAS
> loops to atomic adds
> --------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-16072
> URL: https://issues.apache.org/jira/browse/CASSANDRA-16072
> Project: Cassandra
> Issue Type: Improvement
> Components: Consistency/Hints, Local/Commit Log
> Reporter: Michael Semb Wever
> Assignee: Michael Semb Wever
> Priority: Normal
> Fix For: 3.11.x, 4.0-beta
>
>
> Follow up to CASSANDRA-15922
> Both CommitLogSegment and HintsBuffer use AtomicIntegers for the current
> offset when allocating. Like in CASSANDRA\-15922 the loops on
> {{.compareAndSet(..)}} can be replaced with atomic adds using the {{.
> getAndAdd(..)}} method.
> In highly contended environments the CAS failures can be high, starving
> writes in a running Cassandra node. On the same cluster CASSANDRA\-15922 was
> found, after CASSANDRA\-15922's fix was deployed, there was still problems
> around commit log flushing and hints. No flamegraph was collected that
> demonstrated the thread contention as clearly as was found in
> CASSANDRA\-15922, but the performance fix proposed here hopefully is obvious
> enough.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
