Damien: thanks for the hint, I've tried xtruby. On date/time intensive requests, it was 10% faster. On rendering intensive operations it was 1-2% slower than MRI. But it couldn't finish our database intensive benchmarks - there's no error from xtruby, but our checks reported incorrect response from server.

Charles: Yes, I used server VM and Java 6. The command I used to run was: jruby -J-Xmn512m -J-Xms2048m -J-Xmx2048m -J-server -J-Djruby.compile.mode=JIT -J-Djruby.jit.threshold=0 Unfortunately, Acunote didn't run at all with jruby --fast. Also enabling some other compiler optimizations had negative effect on stability. Sometimes, after N'th repetition of the same request, the test to assert that request was ok, failed. N varied from 20 to 40. It would be cool if we could sit together sometime at RailsConf and try to make it faster. I'm really interested to see how fast JRuby should be.

Delano: Our test process is this: The app runs in the mode that closely resembles production. For Ruby 1.8 and 1.9 we execute 1 warmup request (more isn't necessary, because we only need to warmup database and load all ruby code). JRuby runs with JIT enabled and with JIT threshold 0. Experiments revealed that we need up to 40 warmup requests for JRuby.

Ivar: thanks for the 1.9 mode hint, will try. Will also try 1.3RC1.

Thanks, fixed