[pypy-dev] Performance challenge of mutating class variables

[Maciej Fijalkowski]

On Tue, May 17, 2011 at 1:24 PM, Armin Rigo <arigo at tunes.org> wrote:
> Hi David,
>
> On Sun, May 15, 2011 at 5:21 PM, Armin Rigo <arigo at tunes.org> wrote:
>>> Did you try this with PyPy 1.5 or a recent nightly? I thought that the new
>>> type __dict__ implementation should have fixed the problem?
>>
>> Indeed, with a recent PyPy things are much better.  My example
>> still takes 1.5x time the time it takes on CPython 2.7, though...
>
> Well, I cannot reproduce this number... I have no clue how I got it :-(
>
> The original code you posted is actually not relevant to the JIT: it
> contains no loop.  The fact is that it is still 2-3x faster on PyPy
> than CPython, for GC reasons: our GC is better at handling quickly
> growing heaps, and the allocated objects are much smaller anyway.
>
> The code I posted used to be really slow in pypy-1.5, because it was
> trying again and again to JIT it.  Now we fixed the issue, and it is
> again much faster than CPython (this time, about 10x).

Might be CPython 2.6 vs CPython 2.7? There were significant GC changes
in 2.7, especially when it comes to O(n^2) behavior.

>
>
> A bientôt,
>
> Armin.
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