Python 3.13t is making the news (or atleast one corner of it) quite frequently, the major driver being the fact that this is the first version with the Global Interpreter Lock disabled. This means that potentially Python is no longer constrained from being single-threaded.

Hold your horses, though, free-threaded Python has been released only experimentally. It remains to be seen whether there's benefit (and risk) to machine learning and analytics workloads.

This repository is to provide a helping hand in installing Python 3.13t for experimentation.

Installation is as per users' comfort. Based on resources available to me, I provide below steps to install the same on a Mac with M1 Pro.

Install using a package manager, Homebrew

 brew update && brew upgrade pyenv

and a Python version manager called pyenv

pyenv install 3.13t-dev

Your log should look similar to the following. Once pyenv makes 3.13t available, test it by opening Python in the command line.

Hint - the first line of the command-line utility, and the fact that exit (instead of exit()) allows you to close Python, should be a sign that installation has gone well.

sinsrn@mld420 ~ % pyenv install 3.13t-dev           
python-build: use openssl@3 from homebrew
python-build: use readline from homebrew
Cloning https://github.com/python/cpython...
Installing Python-3.13-dev...
python-build: use readline from homebrew
python-build: use zlib from xcode sdk
Installed Python-3.13-dev to /Users/sinsrn/.pyenv/versions/3.13t-dev
sinsrn@mld420 ~ % $HOME/.pyenv/versions/3.13t-dev/bin/python3.13t

For regular use, however, I seriously recommend using virtual environments.

% $HOME/.pyenv/versions/3.13t-dev/bin/python3.13t -m venv py313t

. py313t/bin/activate

Run the attached check_version.py file.

(py313t) % python3.13t check_version.py

The function is_gil_enable() should return false.

For comparison purposes, also install Python 3.13 (without the free-threaded option)

pyenv install 3.13

% $HOME/.pyenv/versions/3.13.0/bin/python3.13 -m venv py313

. py313/bin/activate

TBD. But, a starter program which illustrates and provides a nice intro, is here. Run with the 3.13t and just the 3.13 environment for a more apples-to-apples.

Meanwhile, some quick reviews of articles which have talked about 3.13t.

A quick test with an attempt to run two threads results in the following, roughly 40% faster.

# Output from Python 3.13 - single threaded

# Total: 49999995000000
# Total: 49999995000000
# --- 0.6976718902587891 seconds ---

# Output from Python 3.13t - free threaded
# Total: 49999995000000
# Total: 49999995000000
# --- 0.4113438129425049 seconds ---

1. Stack Overflow discussion

2. Python installation docs for Mac

Contact Sundaresh Sankaran