[Python-Dev] Python 3.3 vs. Python 2.7 benchmark results (again, but this time more solid numbers)

[Gregory P. Smith]

One word: profile.

Looking at stat counts alone rather than measuring the total time spent in
all types of system calls from strace and profiling is not really useful. ;)

Another thing to keep an eye out for within a startup profile:  how often
does the gc collect?  our default gc collection thresholds haven't been
tuned in ages afaik [or am i forgetting something] and I know of
pathological cases at work where simply doing a gc.disable() before
importing a bunch of modules (tons of generated protocol buffer code) and
re-enabling it afterwards speeds up this application's startup way more
significantly than seems healthy in 2.x... that could be related to the
particulars of the protobuf module code though.

-gps

On Sat, Oct 27, 2012 at 4:00 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:

> On Sun, 28 Oct 2012 01:39:42 +0300
> Serhiy Storchaka <storchaka at gmail.com> wrote:
>
> > On 28.10.12 01:06, Brett Cannon wrote:
> > > I really doubt that as the amount of stat calls is significantly
> reduced
> > > in Python 3.3 compared to Python 3.2 (startup benchmarks show Python
> 3.3
> > > is roughly 1.66x faster than 3.2 thanks to caching filenames in a
> > > directory).
> >
> > $ strace ./python -c '' 2>&1 | grep -c stat
> >
> > Python 2.7 - 161 stats
> > Python 3.2 - 555 stats
> > Python 3.3 - 243 stats
>
> This will probably depend on the length of sys.path:
>
> $ strace -e stat python2.7 -Sc "" 2>&1 | wc -l
> 35
> $ strace -e stat python3.2 -Sc "" 2>&1 | wc -l
> 298
> $ strace -e stat python3.3 -Sc "" 2>&1 | wc -l
> 106
>
> $ strace -e stat python2.7 -c "" 2>&1 | wc -l
> 200
> $ strace -e stat python3.2 -c "" 2>&1 | wc -l
> 726
> $ strace -e stat python3.3 -c "" 2>&1 | wc -l
> 180
>
> Regards
>
> Antoine.
>
>
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