Hands-On Enterprise Application Development with Python

The story of GIL

What if someone told you that, even though you have created a multithreaded program, only a single thread can execute at a time? This situation used to be true when systems consisted of a single core that could execute only one thread at a time, and the illusion of multiple running threads was created by the CPU switching between threads frequently.

But this situation is also true in one of the implementations of Python. The original implementation of Python, also known as CPython consists of a global mutex also known as a GIL, which allows only one thread to execute the Python bytecode at a time. This effectively limits the application to executing only one thread at a time.

The GIL was introduced in CPython because of the ...