What is GIL in CPython

Question

What is the global interpreter lock in CPython? What is the issue about removing GIL from Python?

Answer 1

Python's GIL is intended to serialize access to interpreter internals from different threads. On multi-core systems, it means that multiple threads can't effectively make use of multiple cores. If the GIL didn't lead to this problem, most people wouldn't care about the GIL - it's only being raised as an issue because of the increasing prevalence of multi-core systems.