[Python-Dev] Speeding up CPython 5-10%

Yury Selivanov yselivanov.ml at gmail.com
Mon Feb 1 11:54:17 EST 2016

On 2016-01-29 11:28 PM, Steven D'Aprano wrote:
> On Wed, Jan 27, 2016 at 01:25:27PM -0500, Yury Selivanov wrote:
>> Hi,
>> tl;dr The summary is that I have a patch that improves CPython
>> performance up to 5-10% on macro benchmarks.  Benchmarks results on
>> Macbook Pro/Mac OS X, desktop CPU/Linux, server CPU/Linux are available
>> at [1].  There are no slowdowns that I could reproduce consistently.
> Have you looked at Cesare Di Mauro's wpython? As far as I know, it's now
> unmaintained, and the project repo on Google Code appears to be dead (I
> get a 404), but I understand that it was significantly faster than
> CPython back in the 2.6 days.
> https://wpython.googlecode.com/files/Beyond%20Bytecode%20-%20A%20Wordcode-based%20Python.pdf

Thanks for bringing this up!

IIRC wpython was about using "fat" bytecodes, i.e. using 64bits per 
bytecode instead of 8.  That allows to minimize the number of bytecodes, 
thus having some performance increase.  TBH, I don't think it was 
"significantly faster".

If I were to do some big refactoring of the ceval loop, I'd probably 
consider implementing a register VM.  While register VMs are a bit 
faster than stack VMs (up to 20-30%), they would also allow us to apply 
more optimizations, and even bolt on a simple JIT compiler.


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