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https://issues.apache.org/jira/browse/CASSANDRA-10702?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Paulo Motta updated CASSANDRA-10702:
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Attachment: 10702-v2.patch
Just noticed some trailing whitespaces in the original patch. Attached v2
removing trailing whitespaces and moving ConcGCThreads comment to before the
ConcGCThreads options.
> Statement concerning default ParallelGCThreads in jvm.options is not correct
> ----------------------------------------------------------------------------
>
> Key: CASSANDRA-10702
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10702
> Project: Cassandra
> Issue Type: Bug
> Components: Configuration
> Reporter: Nate McCall
> Assignee: Nate McCall
> Priority: Trivial
> Attachments: 10702-v2.patch, 10702.patch
>
>
> from {{jvm.options}}:
> bq. The JVM maximum is 8 PGC threads and 1/4 of that for ConcGC.
> This is not correct. If there are more than eight CPUs, the default becomes
> 5/8 of the number of CPUs rounded up to the nearest even number (it seems -
> see below). See {{-XX:ParallelGCThreads=n}} secion of
> http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html
> Pretty easy to test with > 16 cores (as 5/8 of such is 10): turn on GC
> logging, leave the defaults, and the G1GC output will show something like:
> {noformat}
> [Parallel Time: 342.6 ms, GC Workers: 16]
> {noformat}
> on a 24 core system in this case.
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