1. Ruby will support parallelization, it’s just a matter of time. 2.Passenger and Unicorn are multi-process, which due to developers can make use of nearly no

1. Ruby will support parallelization, it’s just a matter of time. 2.Passenger and Unicorn are multi-process, which due to developers can make use of nearly nothing in Ruby, and that's why gems like https://github.com/grosser/parallel https://github.com/grosser/parallel come out. 3. The language implementation detail matters a lot. Too many gems are not thread-safe. JRuby is an option, but not that good, as there're too many other options under JVM platform. Rubininus is awesome, I wish it comes out earlier.