[New-bugs-announce] [issue41601] Performance issue using isspace() in extension module on Windows

[Clemens]

New submission from Clemens <cwestphal at gams.com>:

Function isspace() is significantly slower in extension modules in Python 3.7 or later than in Python 3.6 on Windows 10.

Python 3.6:
>python test.py
Locale: C
Set locale: C
Locale: C
Duration: 0.19718074798583984

Python 3.7:
>python test.py
Locale: C
Set locale: C
Locale: C
Duration: 2.9086477756500244

Python 3.8:
>python test.py
Locale: LC_COLLATE=C;LC_CTYPE=English_Germany.1252;LC_MONETARY=C;LC_NUMERIC=C;LC_TIME=C
Set locale: C
Locale: C
Duration: 2.99224853515625

Python 3.9.0a5:
>python test.py
Locale: LC_COLLATE=C;LC_CTYPE=English_Germany.1252;LC_MONETARY=C;LC_NUMERIC=C;LC_TIME=C
Set locale: C
Locale: C
Duration: 2.90370512008667

Building the extension module:
> python setup.py build_ext

A similar issue already exists, but I am not sure if it is the same problem since the suggested solution is about embedding Python rather then extending it: https://bugs.python.org/issue35195

----------
components: Distutils, Windows
messages: 375722
nosy: Clemens, dstufft, eric.araujo, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: Performance issue using isspace() in extension module on Windows
type: performance
versions: Python 3.7, Python 3.8, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue41601>
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