[pypy-dev] My experience with PyPy

[Maciej Fijalkowski]

On Sat, Dec 24, 2011 at 3:46 PM, Michael Sioutis <papito.dit at gmail.com> wrote:
> Hello!
>
> I haven't been following the list, cause I joined yesterday in order to
> share my impressions
> of PyPy here, so I don't know if these kinds of posts are frequent and
> annoying.

Hi Michael

They're more than welcome here. PyPy lacks a bit lots of success
stories, so we definitely welcome each of them

>
> I'm using PyPy the last few weeks in a qualitative spatial reasoner I am
> developing. The speedup is up to
> 10 times over CPython, and it grows even more as the input size grows
> bigger, but that's not what impressed
> me the most, because I was expecting that.
>
> You can find in my presentation here at slides 25 and 33 some comparison
> diagrams against C (red color) and C++
> (blue color) implementations of analogous reasoners.
> I am using different data structures and slightly modified algorithms, so
> you should not consider that the comparison
> diagrams is upon the exact same piece of code.
> Long story short, you will find out that the pypy reasoner ranks in
> positions 1 and 2 respectively, and I believe it will
> also rank 1 in the second diagram if I grow the input even more (I currently
> don't have enough memory and the C implementation
> tops it at 900 nodes, so it would be unreasonable and unfair to run on my
> own).
>
> The impressive part of both diagrams is the scalability pypy offers me. It
> starts slower than the statically compiled languages,
> but the more you push the input sizes, the faster it goes compared to the
> other two.
>
> I started developing the reasoner in python not necessarily to be fast in
> timings, but because I want to go beyond the state of the art in
> qualitative spatial reasoning and present sth new, so python was the
> language of choice to do it fast, in terms of working hours :)
> This is future work, that will be based on the current reasoner.
>
> Thank you for being patient, if you actually took the time to read my story,
> and have a Merry Xmas!
> Mike
>
>

This is all very impressive!

The reason why pypy "scales" well is probably because JIT takes time
to kick in, so for the short-running examples it does not run at the
full speed. It's really cool to see PyPy enabling people to do *really
cool stuff* in Python, that was not entirely possible before. Makes us
want to work harder :)

Thanks for sharing this!

Cheers,
fijal