[Python-Dev] PEP 563: Postponed Evaluation of Annotations

Luca Sbardella luca.sbardella at gmail.com
Fri Nov 3 20:09:24 EDT 2017


Impressive stats! I didn’t know this command, thanks!

On Fri, 3 Nov 2017 at 20:47, Barry Warsaw <barry at python.org> wrote:

> On Nov 2, 2017, at 23:22, Nick Coghlan <ncoghlan at gmail.com> wrote:
> > Another point worth noting is that merely importing the typing module
> > is expensive:
> >
> > $ python -m perf timeit -s "from importlib import reload; import
> > typing" "reload(typing)"
> > .....................
> > Mean +- std dev: 10.6 ms +- 0.6 ms
> >
> > 10 ms is a *big* chunk out of a CLI application's startup time budget.
>
> Far and away so, except for the re module.
>
> % ./python.exe -X importtime -c "import typing"
> import time: self [us] | cumulative | imported package
> import time:        72 |         72 |     _codecs
> import time:       625 |        696 |   codecs
> import time:       354 |        354 |   encodings.aliases
> import time:       713 |       1762 | encodings
> import time:       198 |        198 | encodings.utf_8
> import time:        98 |         98 | _signal
> import time:       233 |        233 | encodings.latin_1
> import time:       353 |        353 |     _weakrefset
> import time:       264 |        617 |   abc
> import time:       402 |       1018 | io
> import time:       136 |        136 |       _stat
> import time:       197 |        333 |     stat
> import time:       227 |        227 |       genericpath
> import time:       377 |        604 |     posixpath
> import time:      2812 |       2812 |     _collections_abc
> import time:       787 |       4534 |   os
> import time:       315 |        315 |   _sitebuiltins
> import time:       336 |        336 |   sitecustomize
> import time:       114 |        114 |   usercustomize
> import time:      1064 |       6361 | site
> import time:       160 |        160 |       _operator
> import time:      1412 |       1571 |     operator
> import time:       371 |        371 |     keyword
> import time:       817 |        817 |       _heapq
> import time:       762 |       1579 |     heapq
> import time:       272 |        272 |     itertools
> import time:       635 |        635 |     reprlib
> import time:        99 |         99 |     _collections
> import time:      3580 |       8104 |   collections
> import time:       112 |        112 |       _functools
> import time:       781 |        892 |     functools
> import time:      1774 |       2666 |   contextlib
> import time:       272 |        272 |       types
> import time:       861 |       1132 |     enum
> import time:        76 |         76 |       _sre
> import time:       426 |        426 |         sre_constants
> import time:       446 |        872 |       sre_parse
> import time:       414 |       1361 |     sre_compile
> import time:        79 |         79 |     _locale
> import time:       190 |        190 |     copyreg
> import time:     17200 |      19961 |   re
> import time:       374 |        374 |   collections.abc
> import time:     15124 |      46226 | typing
>
> -Barry
>
> _______________________________________________
> Python-Dev mailing list
> Python-Dev at python.org
> https://mail.python.org/mailman/listinfo/python-dev
> Unsubscribe:
> https://mail.python.org/mailman/options/python-dev/luca.sbardella%40gmail.com
>
-- 
http://lucasbardella.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20171104/9cdeb03b/attachment.html>


More information about the Python-Dev mailing list