New submission from Craig Holmquist:
Running the attached test script:
$ time python test.py enum
real 0m6.546s
user 0m6.530s
sys 0m0.007s
$ time python test.py int
real 0m0.384s
user 0m0.377s
sys 0m0.000s
I encountered this with a script that yielded a sequence of objects
(potentially a few hundred thousand of them) and categorized them with
instances of an Enum subclass. The consumer of that iteration processes each
object with a switch-case-like comparison of the category, checking it
sequentially against each instance of the Enum. This seems like a fairly
common use case.
>From cProfile it looks like EnumMeta.__getattr__ and _is_dunder are the main
>bottlenecks:
[...]
7/1 0.000 0.000 0.000 0.000 abc.py:194(__subclasscheck__)
1 0.000 0.000 0.001 0.001 enum.py:1(<module>)
3 0.000 0.000 0.000 0.000 enum.py:132(<genexpr>)
2000021 0.988 0.000 0.988 0.000 enum.py:16(_is_dunder)
19 0.000 0.000 0.000 0.000 enum.py:24(_is_sunder)
2000002 1.825 0.000 2.813 0.000 enum.py:241(__getattr__)
17 0.000 0.000 0.000 0.000 enum.py:282(__setattr__)
3 0.000 0.000 0.000 0.000 enum.py:342(_get_mixins_)
3 0.000 0.000 0.000 0.000 enum.py:387(_find_new_)
[...]
----------
components: Library (Lib)
files: test.py
messages: 236234
nosy: craigh
priority: normal
severity: normal
status: open
title: Enum comparisons are 20x slower than comparing equivalent ints
type: performance
versions: Python 3.4
Added file: http://bugs.python.org/file38177/test.py
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<http://bugs.python.org/issue23486>
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