Threading vs Multiprocessing: Python Performance Tip

Quick Python Tip: Multithreading Threading vs Multiprocessing: The Python Tip That Finally Made Everything Click Some use threading thinking it would “make things faster.” Sometimes it did… and sometimes it made everything worse Here’s the simple rule they wish they learned earlier: If you’re waiting -> use threading If you’re computing -> use multiprocessing That’s it. That’s the game-changer. Threading is bad for: - Heavy calculations - Data / image / video processing - ML workloads Threading is great for: - API calls - File & DB I/O - Network requests - Web scraping Modern Python move 👇 - Use ThreadPoolExecutor, not manual `Thread()` - Set a smart pool size (10–20 threads for most I/O) - Always use timeouts - Process results with as_completed() - Avoid shared state when possible Big reality check: Python’s GIL means threads don’t run CPU code in parallel. So threading ≠ faster math. It’s just better at waiting. Your decision framework now: • Waiting on I/O → Threading • Crunching CPU → Multiprocessing • Both? → Multiprocessing + threading inside Tip Summary: Stop creating threads manually. Start managing concurrent I/O the right way. Have you ever used threading expecting speed… and got nothing? What was the task?

  • No alternative text description for this image

Before 3.14 that No-GIL wasn't a thing, threading could in some cases be used for heavy computational functions too. If a function is written in extension modules, it can release the GIL. Some famous libraries do that for some of their functions and let other python code runs in parallel. Tensorflow for example: https://github.com/tensorflow/tensorflow/blob/d23a77161813cb194995012dd227ac732335bfa6/tensorflow/python/client/tf_session_helper.cc#L408 Numpy: https://github.com/search?q=repo%3Anumpy%2Fnumpy+NPY_BEGIN_THREADS&type=code

To view or add a comment, sign in

Explore content categories