[pypy-dev] performance problems with Krakatau

[Robert Grosse]

What would be the best way to provide this?


On Wed, Jan 15, 2014 at 8:39 AM, Maciej Fijalkowski <fijall at gmail.com>wrote:

> On Tue, Jan 14, 2014 at 11:38 PM, Robert Grosse <n210241048576 at gmail.com>
> wrote:
> > Hi, I have been trying to use Pypy to speed up the Krakatau decompiler
> > (https://github.com/Storyyeller/Krakatau). It is a large, pure Python
> > application with several compute intensive parts, so I thought it would
> work
> > well. Unfortunately, there is no clear speedup, and Pypy requires several
> > times as much memory as well, making it unusual for larger inputs.
> >
> > For example, decompiling a quarter of ASM, I got the following results
> > (execution time, memory usage)
> >
> > cpython 64 -  62.5s, 102.6kb
> > cpython 32 -  69.2s,  54.5kb
> > pypy 2.1.0 - 106.5s, 277.8kb
> > pypy 2.2.1 - 109.2s, 194.6kb
> >
> > Sometimes, 2.2.1 is faster than 2.1.0, but they're both clearly much
> worse
> > than CPython.
> >
> > These tests were performed on Windows 7 64bit using the prebuilt 32bit
> > binaries of Pypy. I tested the 32bit version of CPython too, to see if
> the
> > problem was a lack of 64bit support. However, CPython 32bit also vastly
> > outperformed Pypy.
> >
> > Execution time was measured using time.time(). Memory usage was measured
> by
> > watching the Windows Resource Manager and recording the peak Private
> value.
> > Similar patterns were seen in Working Set, etc.
> >
> > I thought the increased memory usage at least might be explained by
> constant
> > overhead from compiled code or from it not running long enough to trigger
> > full garbage collection. However, Pypy continues to use several times as
> > much memory on much larger examples.
> >
> > Does anyone know what could be going on here? Pypy isn't normally slower
> > than CPython. Is there a way for me to tell what the problem is?
>
> Hi.
>
> It depends on your workload a lot. If you want us to have a look into
> it, you need to provide a clear and reproducible way to run a
> benchmark.
>
> Cheers,
> fijal
>
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