Hello, I would like to mention that I've written a patch which enables "threaded interpretation" on the ceval loop with gcc (*). On my computer (an Athlon X2 3600+), it is good for a 15-20% speedup of the interpreter on pystone and pybench. I also had the opportunity to test it on a Core2-derived CPU, where it doesn't make a difference (I conjecture it's because Core2 CPUs have hardware-based indirect branch optimizations). It will make no difference if the interpreter is compiled with something else than gcc (I tested on Windows). The additional complexity is very small. There's a separate script which is run to build the dispatch table (only if needed, that is if dis.py has been modified). In ceval.c, there are a couple of macros and some #ifdef's. That's all. It breaks no test in the regression suite. Could other people test and report their results here? (the patch is for py3k, btw). Also, what are you thoughts for/against integrating this patch in the standard interpreter? Regards Antoine. (*) please note: it has nothing to see with multithreading.