To fulfill the expectations of all Python people who followed me, I'll start sharing some of the Python stuff I'm dealing with now. E.g. right now I'm working on adding asyncio call stack introspection support both from within the process and from outside of it. ✨ 🧵 - ThreadSky

1st1.dev • 94 days ago

To fulfill the expectations of all Python people who followed me, I'll start sharing some of the Python stuff I'm dealing with now. E.g. right now I'm working on adding asyncio call stack introspection support both from within the process and from outside of it. ✨

🧵

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smiz.bsky.social•94 days ago

How does one go about contributing to cpython anyway?

1st1.dev•94 days ago

Start by fixing things you want to change or improve. Join https://discuss.python.org and start reading what community is discussing there.

1st1.dev•94 days ago

What does "outside" mean? It means that sampling profilers and remote debuggers will be able to see into your asyncio program without it becoming any slower or you doing anything. Multiple big companies want this (Meta, Bloomberg, etc.) but even smaller ones like mine (https://edgedb.com) also would benefit

1st1.dev•94 days ago

The most recent mind blowing finding was that somehow, our branch made asyncio 25% slower on some benchmarks, which was completely unexpected for me. Here's a link to the PR by the way: https://github.com/python/cpython/pull/124640

1st1.dev•94 days ago

I wrote a rather involved stress microbenchmark and didn't observe any difference. Then @pablogsal.com came and did his thing, uncovering the actual culprit: asyncio.gather() got significantly slower. Something was wrong with 'lambda' functions in it.

1st1.dev•94 days ago

Upon further investigation, apparently wrapping a single callback in a lambda expression, significantly increased number of Python objects created and skyrocketed pressure on GC. Any code that used gather() heavily could become significantly slower. This patch fixed it entirely.

1st1.dev•94 days ago

Here's my final comment explaining it in bit more detail. https://github.com/python/cpython/pull/124640#issuecomment-2496222355

I'm not sure how soon we merge this though. The PR already clocks 246 comments on it and >2,800 lines of new code. It and it seems we're still not quite done.

I originally estimated this to take one week at most 🤦‍♂️

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