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https://issues.apache.org/jira/browse/CASSANDRA-1968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12980364#action_12980364
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Peter Schuller commented on CASSANDRA-1968:
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Hmmm. The young gen will also directly affect the pause times for most
collection pauses, as I'm sure you're aware. Depending on total heap size and
depending on CPU count, 1/4 heap going to young gen might be huge and cause
significant pause times.
It's certainly expected that larger young gens, up to a point, increase
performance by avoiding promotion to old-gen, but should the out-of-the-box
settings be so aggressive given the potential effects on latency?
How about something like min(max_sensible_default, 1/4 heap size) or perhaps
min(max_sensible_per_modern_cpu_core*num_cores, 1/4 heap size)?
> Increase JVM young generation size
> ----------------------------------
>
> Key: CASSANDRA-1968
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1968
> Project: Cassandra
> Issue Type: Improvement
> Affects Versions: 0.7.0
> Reporter: Brandon Williams
> Assignee: Brandon Williams
> Fix For: 0.7.1
>
> Attachments: 1968.txt
>
>
> Increasing the young generation size has a profound effect on performance and
> cpu utilization. We should set it explicitly.
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