Major GC occurring before CMS occupancy fraction

Bernd Eckenfels ecki at
Wed Nov 19 01:13:37 UTC 2014


you need to provide verbose GC logs so we can say anything on that. But
be aware that you might not get much help on ancient Java :) 

Can you try to set the initial perm size to the maximum size, to make
sure resizes in this area do not trigger GC. And are you sure you are
not confronted with RMI DGC runs?


 Am Tue, 18
Nov 2014 12:24:23 -0500 schrieb nitin sharma
<kumarsharma.nitin at>:

> hi,
> I am facing the same issue.. We are using JDK 1.6. 0_23 and have set
> Occupancy Fraction to 80% but i can see CMS triggered at much below
> ration (around 53%)..
> is there a solution for same?
> I have used "-XX:CMSInitiatingOccupancyFraction=80
> -XX:+UseCMSInitiatingOccupancyOnly" option...
> complete JVM argument set ==>
> /usr/java/jdk1.6.0_23/bin/java -server -Xms16384m -Xmx16384m
> -XX:PermSize=512m -XX:MaxPermSize=1024m -XX:CompileThreshold=8000
> -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps
> -XX:+PrintGCTimeStamps -XX:+UseParNewGC -XX:MaxNewSize=6144m
> -XX:NewSize=6144m -XX:+UseConcMarkSweepGC -XX:ParallelGCThreads=4
> -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled
> -XX:CMSInitiatingOccupancyFraction=80
> -XX:+UseCMSInitiatingOccupancyOnly -DUseSunHttpHandler=true
> -XX:+HeapDumpOnOutOfMemoryError
> Regards,
> Nitin Kumar Sharma.

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