Except doing this through Ruby is a guaranteed bet to not get done in time.

I agree that the gem mentioned might not be suitable, but Ruby could still have a part to play, especially as it allows direct use of native libraries, or just managing processes running on the OS.

Someone doing this should probably write the fast-spinning cogs in C, but it might be worth using Ruby to manage threads, processes, data segments, etc - indeed, maybe prototype the C code there first too. You'd gain an awful lot of convenience for very little overhead.