JVM performance tuning for large applications

Question

The default JVM parameters are not optimal for running large applications. Any insights from people who have tuned it on a real application would be helpful. We are running the

Answer 1

This will be highly dependent on your application and the vendor and version of the JVM. You need to be clear about what you consider to be a performance problem. Are you concerned with certain critical sections of code? Have you profiled the app yet? Is the JVM spending too much time garbage collecting?

I would probably start with the -verbose:gc JVM option to watch how garbage collecting is working. Many times, the simplest fix to just increase the max heap size with -Xmx . If you learn to interpret the -verbose:gc output, it will tell you nearly all you need to know about tuning the JVM as a whole. But doing this alone will not magically make badly tuned code just go faster. Most of the JVM tuning options are designed to improve the performance of the garbage collector and/or memory sizes.

For profiling, I like yourkit.com