What is GIL and how to bypass it?

GIL (Global Interpreter Lock) is a mechanism in CPython that ensures only one thread executes Python bytecode at a time. This limits parallelism in multi-threaded Python programs, especially for CPU-bound tasks.

How to bypass GIL:

1. Multiprocessing — run multiple processes instead of threads. Each process has its own interpreter and GIL, allowing the use of multiple CPU cores.

from multiprocessing import Pool

def f(x):
    return x*x

with Pool(4) as p:
    print(p.map(f, [1, 2, 3, 4]))

2. Using C extensions or libraries that release GIL — for example, NumPy, which performs computations in C and does not block GIL.

3. Asynchronous programming (asyncio) — suitable for I/O-bound tasks where GIL is not a bottleneck.

4. Using alternative Python implementations — such as Jython or IronPython, where GIL is absent.

Thus, for CPU-intensive tasks, it is better to use multiprocessing, and for I/O-bound tasks, multithreading or asyncio.