[ 
https://issues.apache.org/jira/browse/CASSANDRA-16072?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17186739#comment-17186739
 ] 

Michael Semb Wever edited comment on CASSANDRA-16072 at 8/28/20, 6:08 PM:
--------------------------------------------------------------------------

[~blerer], {{HintsBuffer}} look should better now.

Patches
 - 
[3.11|https://github.com/apache/cassandra/compare/cassandra-3.11...thelastpickle:mck/cassandra-3.11_cas_improvements]
 with CI 
[run|https://ci-cassandra.apache.org/blue/organizations/jenkins/Cassandra-devbranch/detail/Cassandra-devbranch/294/pipeline]
 - 
[trunk|https://github.com/apache/cassandra/compare/trunk...thelastpickle:mck/trunk_cas_improvements]
 with CI 
[run|https://ci-cassandra.apache.org/blue/organizations/jenkins/Cassandra-devbranch/detail/Cassandra-devbranch/295/pipeline]





was (Author: michaelsembwever):
[~blerer], {{HintsBuffer}} look should better now.

Patches
 - 
[3.11|https://github.com/apache/cassandra/compare/cassandra-3.11...thelastpickle:mck/cassandra-3.11_cas_improvements]
 with CI 
[run|https://ci-cassandra.apache.org/blue/organizations/jenkins/Cassandra-devbranch/detail/Cassandra-devbranch/292/pipeline]
 - 
[trunk|https://github.com/apache/cassandra/compare/trunk...thelastpickle:mck/trunk_cas_improvements]
 with CI 
[run|https://ci-cassandra.apache.org/blue/organizations/jenkins/Cassandra-devbranch/detail/Cassandra-devbranch/293/pipeline]




> 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: commits-unsubscr...@cassandra.apache.org
For additional commands, e-mail: commits-h...@cassandra.apache.org

Reply via email to