Tracing JITs in the real world @ CPython Core Dev Sprint
Last week I got to take part in the CPython Core Developer Sprint in Cambridge, hosted by ARM and brilliantly organized by Diego Russo -- about ~50 core devs and guests were there, and I was excited to join as one of the guests.
I had three main areas of focus:
-
C API: this was a follow up of what we discussed at the C API summit at EuroPython. The current C API is problematic, so we are exploring ideas for the development of PyNI (Python Native Interface), whose design will likely be heavily inspired by HPy. It's important to underline that this is just the beginning and the entire process will require multiple PEPs.
-
fancycompleter This is a small PR which I started months ago, to enable colorful tab completions within the Python REPL. I wrote the original version of fancycompleter 15 years ago, but colorful completions work only in combination with PyREPL. Now PyREPL is part of the standard library and enabled by default, so we can finally upstream it. I hope to see it merged soon.
-
"JIT stuff": I spent a considerable amount of time talking to the people who are working on the CPython JIT (in particular Mark, Brandt, Savannah, Ken Jin and Diego). Knowledge transfer worked in both ways: I learned a lot about the internal details of CPython's JIT, and conversely I shared with them some of the experience, pain points and gut feelings which I got by working many years on PyPy.
In particular, on the first day I presented a talk titled Tracing JIT and real world Python (slides and source code).
What follows is an annotated version of the slides.
