[Python-ideas] Expansion of the range of small integers

[Antoine Pitrou]

On Mon, 17 Sep 2012 15:41:23 +0300
Serhiy Storchaka <storchaka at gmail.com>
wrote:
> Now in the CPython small integer numbers from -5 up to 256 inclusive are 
> preallocated at the start. It allows to reduce memory consumption and 
> time of creation of the integers in this range. In particular this 
> affects the speed of short enumerations. Increasing the range to the 
> maximum (from -32767 to 32767 inclusive), we can speed up longer 
> enumerations.
> 
> Microbenchmarks:
> ./python -m timeit  "for i in range(10000): pass"
> ./python -m timeit  -s "a=[0]*10000"  "for i, x in enumerate(a): pass"
> ./python -m timeit  -s "a=[0]*10000"  "i=0"  "for x in a: i+=1"
> ./python -m timeit  -s "a=[0]*10000"  "for i in range(len(a)): x=a[i]"
> 
> Results:
>   non-patched     patched
>     530 usec      337 usec    57%
>    1.06 msec      811 usec    31%
>    1.34 msec     1.13 msec    19%
>    1.42 msec     1.22 msec    16%

See also http://bugs.python.org/issue10044

> 1) Memory consumption increases by constant 1-1.5 MB.

That sounds a bit annoying. Is it for a 32-bit or 64-bit build?

Regards

Antoine.


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