[ https://issues.apache.org/jira/browse/CASSANDRA-9242?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Ellis reassigned CASSANDRA-9242: ----------------------------------------- Assignee: Ariel Weisberg Assigning to Ariel for comment since we discussed briefly on IRC. > 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 > > 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)