#565: Tachyon, Python 3.15's Built-in Sampling Profiler

Do you know what's actually slow in your Python app? Or are you guessing? Until now, profiling Python meant a tracing profiler that made your code 2 to 3 times slower. Or a third-party tool that broke with every new release. Python 3.15 fixes that. It ships Tachyon, a sampling profiler built into the standard library. It attaches to live production apps with almost zero overhead. My guests are Pablo Galindo Salgado, CPython core developer and Steering Council member, and László Kiss Kollár from Bloomberg's Python infrastructure team. Their first prototype ran at two samples a second. Now it does over a million hz. And it lands in Python 3.15 this October. Episode sponsors Sentry Error Monitoring, Code talkpython26 Python in Production Talk Python Courses Links from the show Guests László Kiss Kollár: linkedin.com Pablo Galindo Salgado 3.11: talkpython.fm Memray: talkpython.fm PyStack: talkpython.fm profile and cProfile: docs.python.org py-spy: github.com Austin: github.com PEP 799: peps.python.org PEP 768: peps.python.org PyCon US 2026 talk: us.pycon.org The docs: docs.python.org Backport to 3.14: github.com Watch this episode on YouTube: youtube.com Episode #565 deep-dive: talkpython.fm/565 Episode transcripts: talkpython.fm Theme Song: Developer Rap 🥁 Served in a Flask 🎸: talkpython.fm/flasksong ---== Don't be a stranger ==--- YouTube: youtube.com/@talkpython Bluesky: @talkpython.fm Mastodon: @[e-mail] X.com: @talkpython Michael on Bluesky: @mkennedy.codes Michael on Mastodon: @[e-mail] Michael on X.com: @mkennedy