[jboss-user] [Performance Tuning] - 100% CPU usage with lots of memory

Hi all, We've got an application that stores a large amount of data in-memory which is then used by a lot of users. Subsequently we're seeing CPU usage go through the use, and every now and then hit 100% (on a quad core machine with 8GB of mem) which I believe is when the JVM tries to garbage collect. The web app can't be used until JBoss is killed and restarted. We currently have these JVM opts: JAVA_OPTS="$JAVA_OPTS -Xms5g -Xmx5g -XX:MaxNewSize=3g -XX:PermSize=512m -XX:MaxP ermSize=1g -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterv al=3600000 -Djava.awt.headless=true -d64 -verbose:gc" Which may or may not be causing the problems - my knowledge of GC management is very limited. We see something similar to this in the logs: | [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor451] | [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor24] | [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor450] | [Unloading class sun.reflect.GeneratedSerializationConstructorAccessor458] (lots more) [Full GC 4077824K->4077824K(4660352K), 7.6307480 secs] | [Full GC 4077824K->4077625K(4660352K), 10.7810720 secs] | [Full GC 4077823K->4077823K(4660352K), 7.6245730 secs] | [Full GC 4077823K->4077611K(4660352K), 10.8113030 secs] (lots more) Any help would be much appreciated. JBoss 4.2.1GA SuSE Enterprise 10 SP1 Java 1.6.0_05 View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4137589#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...