What is GIL (Global Interpreter Lock)?

GIL (Global Interpreter Lock) is a mechanism in CPython that ensures that only one thread executes Python bytecode at any given time. This is done to simplify memory management and prevent issues with concurrent access to Python objects.

Due to the GIL, multithreaded programs in Python cannot effectively utilize multiple CPU cores for CPU-bound tasks, as threads are effectively executed sequentially. However, for I/O-bound tasks, where threads often wait for input/output, the GIL is not a bottleneck.

Example: if you want to perform computations in parallel on multiple cores, it is better to use multiprocessing or other approaches that bypass the GIL.