[dataminer]

What kind of computations were you doing on MRI which resulted in such performance boost by switching to JRuby? I have tried Rails under JRuby many times, the performance is the same as 1.9.3 and memory consumption usually higher.

[jacques_chester]

Redmine. Runs faster and smaller per instance of the application.

[jacques_chester]

Looking at my post again, I guess I didn't do a very good job.

I didn't mean 2.5Mb per copy of the JVM. I meant per runtime within the JVM. These are run as threads, rather than processes.

So we're really comparing

    n instances of MRI * 50Mb

vs

    1 JVM + (n * 2.5Mb)

Where the cost of the JVM itself is amortised over the application instances.

Sorry, what I said originally is easily misleading.