Python 3.13 RC2, with and without GIL

Python 3.13 RC2 is now available in Tumbleweed. This new version of the Python interpreter will be released in October 2024.

There is a lot of changes and new features in 3.13, but we’re also bringing exiting experimental features in Tumbleweed.

Experimental JIT compiler

The default (python313) build has the flag --enable-experimental-jit=yes-off. This means that if you want to use this experimental JIT you can enable with an environment variable:

$ PYTHON_JIT=1 python3.13

You can find more information about the JIT compiler and how it can improve performance in PEP-744.

Free threaded CPython (no GIL)

With this new version of Python interpreter, there is an option to build without the famous Global Interpreter Lock, aka GIL. This is a really experimental feature, but why not have this on Tumbleweed? So we decided to build also this new version with a new package python313-nogil.

This new package is an isolated interpreter, so you can install without conflicts with python313. The package is building with the --disable-gil option and it provides the /usr/bin/python3.13t binary. It uses by default /usr/lib/python3.13t/site-packages for third-party libs so, with the default configuration, it won’t use any python 3.13 module.

This means that now you can use threading.Thread in the Python interpreter, and it will be actual threads so, at the end using threads with python3.13t, interpreter should be a lot faster.

There’s no packages for this interpreter in Tumbleweed, at this moment. So if you want to use third party libraries you should use virtualenv and pip for that:

$ python3.13t -m venv free-threaded-env
$ source free-threaded-env/bin/activate
(free-threaded-env) $ pip install requests
(free-threaded-env) $ python3
Python 3.13.0rc2 experimental free-threading build (main, Sep 07 2024, 16:06:06) [GCC] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys; sys._is_gil_enabled()
False