Threading, multiprocessing, asyncio: what is the difference and when is it better to use each?

Threading — this is multithreading, where several threads run within a single process and can work in parallel, but in Python, due to the GIL (Global Interpreter Lock), only one thread executes Python code at a time.

Multiprocessing — this involves running multiple processes, each with its own memory and Python interpreter, which allows bypassing the GIL and executing code in parallel on multiple CPU cores. It is well-suited for CPU-intensive tasks.

Asyncio — this is asynchronous programming using an event loop and coroutines. It allows efficient handling of a large number of I/O operations without creating many threads or processes. Ideal for network applications that need to handle thousands of connections.

When to use what:

• For CPU-bound tasks — multiprocessing.
• For I/O-bound tasks with low levels of parallelism — threading.
• For scalable I/O-bound tasks with many connections — asyncio.

Example of using asyncio:

import asyncio

async def fetch_data():
    await asyncio.sleep(1)  # simulate I/O operation
    return 'data'

async def main():
    results = await asyncio.gather(fetch_data(), fetch_data(), fetch_data())
    print(results)

asyncio.run(main())