jvm tuning

[Mario Almeida]

Hi All,

OS Centos 5.5 64Bit
2 Xeon Quad core 2.66Ghz, 8GB ram
JBOSS 4.2.3.GA
JDK 1.6u21

Can someone help me in tuning JVM

JVM_OPTS=

-Dprogram.name=run.sh -server -d64 -Xss256k -Xmx3g -Xms3g -XX:NewSize=1536m -XX:MaxNewSize=1536m 
-XX:PermSize=180m -XX:MaxPermSize=180m -XX:SurvivorRatio=13 -XX:NewRatio=2 -XX:+UseParNewGC 
-XX:ParallelGCThreads=5 -XX:MaxTenuringThreshold=31 -XX:+AggressiveOpts -XX:TargetSurvivorRatio=90 
-XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=80 -Dsun.rmi.dgc.client.gcInterval=3600000 
-Dsun.rmi.dgc.server.gcInterval=3600000 -Xloggc:/var/log/jboss/gc00.log -verbose:gc -XX:+PrintGCTimeStamps 
-XX:+PrintGCDetails -XX:+PrintTenuringDistribution -XX:+PrintHeapAtGC -Djava.net.preferIPv4Stack=true

Please download gc00.log file from http://213.42.18.44/gc00.log

[SumitPal Pal]

I think you should ask this question - why do you need to do Heap Tuning - are you seeing excessive GC happening - then identify - what GC is happening excessive - Minor one / Major ones.

Is there an issue with the Application - too much object creation etc

Have you tried to answer those questions

Sometimes some 3rd party libraries - call GC explicitly in the code - try to see if you can add this flag
-DisableExplicitGC in the JVM_OPT and see if it reduces the number of GCs

[kri shan]

-XX:PermSize=180m -XX:MaxPermSize=180m
Your PermSize and MaxPermSize are size. Can you increase your MaxPermSize ?