I am running a cluster JBoss servers.
Both server has 4 CPUs, dual cores. i.e. 8 logical CPUs.
I want to tune the JVM setting and I used the following parameters:
I did some load test with different number of ParallelGCThreads.
However, I was surprised from the load test result that, the Full GC time for the UseParallelOldGC is much longer than I didn't use it. E.g.
A) Parallel Old GC = 7
B) Parallel Old GC = 3
C) No Parallel Old GC
Does anyone know any reason why the ParallelOldGC can perform poor?
The JVM configure is as follows:
-Xms2560m -Xmx2560m -XX:NewSize=853m -XX:MaxNewSize=853m -XX:OldSize=1707m -XX:+UseParallelOldGC -XX:+ParallelGCThreads=7 -XX:PermSize=384m -XX:MaxPermSize=384m -Xloggc:/u01/app/jboss_sit/server/all/log/gc.log -Dsun.rmi.dgc.client.gcInterval=36
00000 -Dsun.rmi.dgc.server.gcInterval=3600000 -verbose:gc -XX:+PrintGC
TimeStamps -XX:+PrintGCDetails -XX:SoftRefLRUPolicyMSPerMB=0 -Djavax.net.ssl.sessionCacheSize=30