pypy on windows much slower than linux/mac when using complex number type?

[Chris Kaynor]

On Tue, Sep 20, 2016 at 3:59 PM, Chris Angelico <rosuav at gmail.com> wrote:

> On Wed, Sep 21, 2016 at 8:50 AM, Irmen de Jong <irmen.NOSPAM at xs4all.nl>
> wrote:
> >> Dunno if it's the cause or not, but you're running a 32-bit PyPy on a
> >> 64-bit Windows. I could well imagine that that has some odd
> >> significance.
> >>
> >> ChrisA
> >
> >
> > Perhaps. Though I can't really imagine what's going on there then. The
> one on Linux is
> > 32 bits as well and it's also much faster...
> > Unfortunately there's no 64 bits pypy expected for windows, so I can't
> test that
>
> Yeah, but the Linux one is running in a 32-bit OS. I don't know how
> the "32-bit on 64-bit" subsystem of Windows works and how fast it is;
> it could be that the thunking defeats some optimizations relating to
> floating-point. Who knows. Hard to test.
>

WoW64 shouldn't have any measurable speed decrease. I've run plenty of
32-bit games on a 64-bit Windows (many games are still 32-bit only), and
they always perform fine, regardless of whether they are CPU or GPU bound
based off the profiling I've done. I think most of the cost is paid in the
context switches.

Regarding the performance decrease, it may be worthwhile to push the report
to a PyPy specific forum - a PyPy developer will probably see it here, but
you may get a faster response on a forum specific to PyPy.