Simon Willison’s Weblog


7 items tagged “jit”


Python 3.13 gets a JIT. “In late December 2023 (Christmas Day to be precise), CPython core developer Brandt Bucher submitted a little pull-request to the Python 3.13 branch adding a JIT compiler.”

Anthony Shaw does a deep dive into this new experimental JIT, explaining how it differs from other JITs. It’s an implementation of a copy-and-patch JIT, an idea that only emerged in 2021. This makes it architecturally much simpler than a traditional JIT, allowing it to compile faster and take advantage of existing LLVM tools on different architectures.

So far it’s providing a 2-9% performance improvement, but the real impact will be from the many future optimizations it enables.

# 9th January 2024, 9:25 pm / jit, llvm, python


Announcing Pyston-lite: our Python JIT as an extension module (via) The Pyston JIT can now be installed in any Python 3.8 virtual environment by running “pip install pyston_lite_autoload”—which includes a hook to automatically inject the JIT. I just tried a very rough benchmark against Datasette (ab -n 1000 -c 10) and got 391.20 requests/second without the JIT compared to 404.10 request/second with it.

# 8th June 2022, 5:58 pm / jit, performance, python


Introducing the PyPy 1.2 release. It’s been a long time coming, but 1.2 is the first PyPy release to ship with a Just-in-Time compiler! Performance looks pretty impressive.

# 12th March 2010, 11:54 pm / jit, performance, pypy, python


Right now, pypy compiled with JIT can run the whole CPython test suite without crashing, which means we're done with obvious bugs and the only ones waiting for us are really horrible.

Maciej Fijalkowski

# 1st May 2009, 3:04 pm / bugs, jit, jpython, pypy, python, unittests

ProjectPlan—unladen-swallow. A branch of Python 2.6 aiming to radically improve performance (the target is a 5x improvement), by compiling Python to machine code using LLVM’s JIT engine. I think this is a Google 20% time project (or maybe not, see the comments). An early version without LLVM is already available for download.

# 30th March 2009, 10:09 am / google, jit, llvm, performance, python, unladenswallow

why’s potion. why’s latest project is a small, fast language (JIT to x86/x86-64) which seems to take ideas from Ruby, Lua, Python and who knows where else. Everything is based around objects, closures and mixins, with the delightful inclusion of scoped mixins so you can modify an object only within a certain module (hence avoiding Ruby’s action-at-a-distance problems).

# 8th January 2009, 6:37 pm / closures, jit, languages, lua, mixins, potion, programming, ruby, whytheluckystiff


TraceMonkey. Brendan Eich has been preaching the performance benefits of tracing and JIT for JavaScript on the conference circuit for at least a year, and the results from the first effort to be merged in to Mozilla core are indeed pretty astounding.

# 22nd August 2008, 11:13 pm / brendaneich, javascript, jit, john-resig, mozilla, performance, tracemonkey