Im surprised to see that Sinatra on JRuby often performs worse than Sinatra on MRI, while Rack on the other hand performs much better.
We were surprised by the sinatra-jruby tests as well. If you read our "expected questions" section, it's not clear to us why Sinatra's performance on JRuby was weak. We'd love to hear from a JRuby expert about how to address Sinatra's "wrong" looking numbers.
Glad to see that on Rack, where I'd expect us to be fast...we are doing ok. On par with PHP (not a big thing to brag about, perhaps) and Play (worth bragging about, since it's Java/Scala end to end).
Obviously there's more work needed not just in JRuby but in the servers that server it and the frameworks that run on it. The slow performance of Rails here, for example, is largely Rails' fault.
But yeah...the sinatra numbers are wack.