How to make Ruby or Python web sites to use multiple cores?

Question

Even though Python and Ruby have one kernel thread per interpreter thread, they have a global interpreter lock (GIL) that is used to protect potentially shared data structures, so this inhibits multi-processor execution. Even though the portions in those languajes that are written in C or C++ can be free-threaded, that's not possible with pure interpreted code unless you use multiple processes. What's the best way to achieve this? Using FastCGI? Creating a cluster or a farm of virtualized servers? Using their Java equivalents, JRuby and Jython?

Answer 1

I'm not totally sure which problem you want so solve, but if you deploy your python/django application via an apache prefork MPM using mod_python apache will start several worker processes for handling different requests.

If one request needs so much resources, that you want to use multiple cores have a look at pyprocessing. But I don't think that would be wise.

Answer 2

The 'standard' way to do this with rails is to run a "pack" of Mongrel instances (ie: 4 copies of the rails application) and then use apache or nginx or some other piece of software to sit in front of them and act as a load balancer.

This is probably how it's done with other ruby frameworks such as merb etc, but I haven't used those personally.

The OS will take care of running each mongrel on it's own CPU.

If you install mod_rails aka phusion passenger it will start and stop multiple copies of the rails process for you as well, so it will end up spreading the load across multiple CPUs/cores in a similar way.