[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
>
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