Redmine

It might be interesting to mention hear that the TruffleRuby team is making rapid progress, and I’ve reported a few issues they are actively working on that will eventually allow Redmine (and other production Rails apps) to run, considerably faster than MRI. TruffleRuby is based on JRuby but adds a lot to it. I hope Redmine will officially support it when compatibility is achieved.

TruffleRuby is way less mature that JRuby. Also, it doesn't solve the issue that many external gems used by Redmine do not fully support JRuby (and even less likely TruffleRuby). Thus, while Truffle is interesting, full support for it likely requires a long way to go.

lower your expectations, TruffleRuby will definitely excel in numeric operations (micro-benchmarks), partial evaluation is also an interesting technique, but a webserver is usually limited by IO (handling requests, database access etc.) so I don't expect it'll be MUCH faster.