I understood the problem pretty well before writing the C++ version, having done some prototypes beforehand. The C++ version went through some reasonable refactoring too, so it's not like that code was just the first working version that g++ would accept.

I didn't do a full C++ rewrite of course. I think it's fair to say that whenever you are doing lots of concurrency/multithreading/evented stuff in a language like C++, the savings will be enormous when you switch to a language that has a nice concurrency model (ie, not just threads and shared mem and mutexes).