[pypy-dev] Python vs pypy: interesting performance difference [dict.setdefault]

[Alex Gaynor]

On Mon, Aug 15, 2011 at 2:05 AM, Armin Rigo <arigo at tunes.org> wrote:

> Hi David,
>
> On Sat, Aug 13, 2011 at 8:14 PM, David Naylor <naylor.b.david at gmail.com>
> wrote:
> > So, it appears pypy is failing to speed up this contrived example...
>
> I think that it is expected, because the hash is computed entirely as
> pure Python code in the case of PyPy (doing integer arithmetic with
> overflow checks) whereas it is written in C in the case of RPython.  I
> find it rather good that we get overall close to the speed of CPython,
> given that we just have datetime.py...  Try using datetime.py on top
> of CPython too :-)
>
> More seriously, if we want to be really better with datetime objects,
> as opposed to "good enough for now", then I fear we need to rewrite
> datetime.py in RPython, like CPython did rewrite it in C.  Or some
> intermediate solution is possible too, having an internal class which
> implements only basic operations (like hash) and which is subclassed
> in pure Python.  But I would happily leave that task to someone with
> an absolutely real need for high-performance datetime objects; for me
> "good enough for now" is good enough, for now...
>
>
> A bientôt,
>
> Armin.
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I'd like to express that, unless we have a very compelling reason, we should
try to keep more stuff in pure python, as opposed to RPython.  Mostly
because it speeds up translation ;) (also easier to test, easier to write,
etc.).

Alex

-- 
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"The people's good is the highest law." -- Cicero
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