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

[Brett Cannon]

On Mon, 1 Feb 2016 at 09:08 Yury Selivanov <yselivanov.ml at gmail.com> wrote:

>
>
> 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.
>

If you did tackle the register VM approach that would also settle a
long-standing question of whether a certain optimization works for Python.

As for bolting on a JIT, the whole point of Pyjion is to see if that's
worth it for CPython, so that's already being taken care of (and is
actually easier with a stack-based VM since the JIT engine we're using is
stack-based itself).
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