cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Asif A Bashar (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-9242) Add PerfDisableSharedMem to default JVM params
Date Sat, 29 Aug 2015 00:03:46 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-9242?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14720817#comment-14720817
] 

Asif A Bashar commented on CASSANDRA-9242:
------------------------------------------

After adding this flag, jps command does not show cassandra process anymore. dse cassandra-stop
also does not work.

> Add PerfDisableSharedMem to default JVM params
> ----------------------------------------------
>
>                 Key: CASSANDRA-9242
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9242
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Config
>            Reporter: Matt Stump
>            Assignee: Ariel Weisberg
>             Fix For: 2.2.0 beta 1
>
>
> We should add PerfDisableSharedMem to default JVM params. The JVM will save stats to
a memory mapped file when reaching a safepoint. This is performed synchronously and the JVM
remains paused while this action takes place. Occasionally the OS will stall the calling thread
while this happens resulting in significant impact to worst case JVM pauses. By disabling
the save in the JVM these mysterious multi-second pauses disappear.
> The behavior is outlined in [this article|http://www.evanjones.ca/jvm-mmap-pause.html].
Another manifestation is significant time spent in sys during GC pauses. In [the linked test|http://cstar.datastax.com/graph?stats=762d9c2a-eace-11e4-8236-42010af0688f&metric=gc_max_ms&operation=1_write&smoothing=1&show_aggregates=true&xmin=0&xmax=110.77&ymin=0&ymax=10421.4]
you'll notice multiple seconds spent in sys during the longest pauses.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message