I’ve just read the WM IS46 Performance & Scalability Report, and have a little question which was unanswered by the paper. WM benchmarked Sun’s JDK vs. IBM’s, but they did not mention which of the two JIT compilers (“client” or “server”) they have chosen on the Sun JDK. I’m assuming it is the “server” VM that WM have used, since otherwise additional CPU scalability is zero (in my experience) if the “client” VM is used. Anybody knows?

I use the -server switch in the script startup.

There is a line in the server.sh/bat file that resembles this:

set JAVA_RUN=%JAVA_EXE% %JAVA_MEMSET%

I set the switch:

set JAVA_RUN=%JAVA_EXE% -server %JAVA_MEMSET%

We tried both switches at various points in time though the tests for the whitepaper were done with the default since empirically the results were slightly better (strange but true, at least in our lab).

If running on a Windows OS, the IBM JVM always was the better choice. Sun 1.3.x was better than 1.2.2 but it never got into the same performance level as the IBM JVM.