Performance of int/long in Python 3
Chris Angelico
rosuav at gmail.com
Tue Mar 26 02:26:31 EDT 2013
On Tue, Mar 26, 2013 at 10:35 AM, Cousin Stanley
<cousinstanley at gmail.com> wrote:
>
> Chris Angelico wrote:
>
>> The Python 3 merge of int and long has effectively penalized
>> small-number arithmetic by removing an optimization.
>> ....
>> The cost is clear.
>> ....
>
> The cost isn't quite as clear
> under Debian Wheezy here ....
>
> Stanley C. Kitching
> Debian Wheezy
>
> python inline range_sum forloop forloop_offset
>
> 2.7.3 3.1359 3.0725 9.0778 15.6475
>
> 3.2.3 2.8226 2.8074 13.47624 13.6430
Interesting, so your 3.x sum() is optimizing something somewhere.
Strange. Are we both running the same Python? I got those from
apt-get, aiming for consistency (rather than building a 3.3 from
source).
The cost is still visible in the for-loop versions, though, and you're
still seeing the <2^31 and >2^31 for-loops behave the same way in 3.x
but perform quite differently in 2.x. So it's looking like things are
mostly the same.
ChrisA
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