[Python-Dev] int/float freelists vs pymalloc

[Andrew MacIntyre]

Andrew MacIntyre wrote:
> M.-A. Lemburg wrote:
>> If we're down to voting, here's my vote:
>>
>> +1 on removing the freelists from ints and floats, but not the
>>    small int sharing optimization
>>
>> +1 on focusing on improving pymalloc to handle int and float
>>    object allocations even better
>>
>> -1 on changing the freelist implementations to use pymalloc for
>>    allocation of the freelist members instead of malloc, since
>>    this would potentially lead to pools (and arenas) being held alive
>>    by just a few objects - in the worst case a whole arena (256kB)
>>    for just one int object (14 bytes on 32bit platforms).
>>
>> Eventually, all freelists should be removed, unless there's a
>> significant performance loss.
 >
> Sigh...  things are never as simple as they seem...
> 
> Prompted by your comment about the small int sharing, which I was aware 
> of and was not addressing because I was assuming that its value was 
> unimpeachable, I've been doing some more testing with this and the
> freelists.
> 
> I don't have time to write it up tonight, but I've concluded that my 
> original test scripts and other tests weren't showing the real
> performance of the various approaches.  Platform (architecture, compiler
> etc) oddities & differences complicate life too...

I've now written up my testing and attached the write-up to issue 2039
(http://bugs.python.org/issue2039).

-- 
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Andrew I MacIntyre                     "These thoughts are mine alone..."
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