How do you get profiling to work with the Linux JVMs? The standard bundled profiler, hprof, fails to generate useful output for the options.

Profiling appears to be a big implementation hole in the JVMs, especially the HotSpot JVMs. I've had success using the "cpu=samples" option with the classic JVM in the Sun JDK1.3 (run it as "java -classic ..."), but not with the "cpu=times" or "cpu=old" options. It appears to be a JVM issue, not a Linux issue.