Python code performance decreases with threading

Question

I\'ve written a working program in Python that basically parses a batch of binary files, extracting data into a data structure. Each file takes around a second to parse, whi

Answer 1

This is sadly how things are in CPython, mainly due to the Global Interpreter Lock (GIL). Python code that's CPU-bound simply doesn't scale across threads (I/O-bound code, on the other hand, might scale to some extent).

There is a highly informative presentation by David Beazley where he discusses some of the issues surrounding the GIL. The video can be found here (thanks @Ikke!)

My recommendation would be to use the multiprocessing module instead of multiple threads.