[Python-Dev] Silly little benchmark

[Tim Peters]

[Skip Montanaro]
> ...
> I came up with the following "benchmarks":
>
>     for i in xrange(100000): pass
>     for i in xrange(100000): x = 1
>     for i in xrange(100000): x = ``1`+`2``
>
> user mode times on my computer (sys mode was always 0.0) were
>
>              Python 1.6   Python 2.1   change
>     pass           0.12         0.20    1.67x
>     x = 1          0.17         0.30    1.76x
>     x = ``1`+`2``  1.60         2.13    1.33x

Please don't post stuff with hard tab characters (I took them out by hand so
this wasn't an unreadable mess).

> Startup times (python -S -c 'pass') are 0.0 for both versions on
> my 'puter.  It appears loop execution overhead has gotten substantially
> worse between 1.6 and 2.1.

AFAIK, nothing relevant changed between 1.6 and 2.1.  Anyone else?  Indeed,
AFIAK, *nothing* plausibly relevant about about for-loops or xrange has
changed since 1.5 (when some general eval-loop speedups got done).

> ...
> but it would seem a good time to reserve a minor version for mostly
> performance improvements.  2.3 perhaps?

The loop speedup in 2.2 requires changes in the PVM as well as adopting the
iterator protocol.  If you've got some *easy* performance improvements,
sure, but then I have to wonder why you've been holding them back <wink>.