[Python-Dev] Benchmarks: Comparison between Python 2.7 and Python 3.6 performance

Victor Stinner victor.stinner at gmail.com
Mon Nov 7 18:11:31 EST 2016

2016-11-07 20:20 GMT+01:00 Guido van Rossum <guido at python.org>:
> Re:
> https://speed.python.org/timeline/#/?exe=4&ben=python_startup&env=1&revs=50&equid=off&quarts=on&extr=on
> That's suspiciously close to the core sprint. Since the -S time stayed
> roughly the same I suspect that either a new module was added to the startup
> sequence or one of the (too many) modules already involved grew a lot. My
> money is on a new module. Using `python -v -c pass` on a Python built from
> the Sept. 9 tree and one built from Sept. 15, it shouldn't be too hard to
> figure out which new module(s).

I identified the regression, I created:


It's a regression caused by:


The change added "import enum" in Lib/re.py. I propose to revert this
change for now, and discuss later a solution which doesn't impact

It's nice to see that my work of performance was useful to catch a
performance regression.


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