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

[Antoine Pitrou]

On Sat, 27 Oct 2012 20:38:58 -0700
"Gregory P. Smith" <greg at krypto.org> wrote:
> 
> 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.

http://bugs.python.org/issue16351 shows us that the number of
collections at 3.4 startup is tiny:

$ ./python -Sc "import gc; print(gc.get_stats())"
[{'collections': 6, 'uncollectable': 0, 'collected': 0},
{'collections': 0, 'uncollectable': 0, 'collected': 0},
{'collections': 0, 'uncollectable': 0, 'collected': 0}]

$ ./python -c "import gc; print(gc.get_stats())"
[{'collected': 0, 'uncollectable': 0, 'collections': 12},
{'collected': 0, 'uncollectable': 0, 'collections': 1},
{'collected': 0, 'uncollectable': 0, 'collections': 0}]


Notably, there are no full collections.

Regards

Antoine.