Running cachegrind on OpenJDK JVM

Question

I want to use cachegrind to do some performance profiling on the OpenJDK JVM. (BTW, if this is Not A Good Idea, I would like to understand why.)

The problem is it keeps tripping up assertions in the JVM. So what can I do to get a run using cachegrind. Or else, please tell me why this wouldn't work. And if you can suggest an alternative to cachegrind. (Note that I have looked at and used perf. It's just that I was curious how different a tool like cachegrind/callgrind would be in terms of results.)

Answer 1

Valgrind and the tools based on it are typically not very good for performance profiling. Valgrind is a kind of a virtual machine that does not execute the original code directly but rather translates it. Programs often run much slower under Valgrind, and this can affect the application execution scenario.

Also Valgrind does not work well with the dynamic and self-modifying code. With respect to JVM's JIT compilation this can result in random assertion failures and JVM crashes that you apparently observe. Valgrind is known to be much more stable when Java is run with JIT disabled, i.e. -Xint. But in -Xint mode profiling does not make much sense since it does not reflect the real application performance.

perf is preferable way to do this kind of measurements. perf relies on hardware counters, it does not modify the executed code. For deeper performance analyis there is Intel VTune Amplifier. It is not free though, but a trial version is available.