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gh-74690: Optimise isinstance() and issubclass() calls against runtime-checkable protocols by avoiding costly super() calls #112708

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Merged
merged 3 commits into from
Dec 4, 2023
Merged

gh-74690: Optimise isinstance() and issubclass() calls against runtime-checkable protocols by avoiding costly super() calls #112708

merged 3 commits into from
Dec 4, 2023

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AlexWaygood
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@AlexWaygood AlexWaygood commented Dec 4, 2023 •
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Before:

>python -m timeit -s "from typing import SupportsIndex" "isinstance(0, SupportsIndex)"
Running PGUpdate|x64 interpreter...
1000000 loops, best of 5: 379 nsec per loop

>python -m timeit -s "from typing import SupportsIndex" "issubclass(int, SupportsIndex)"
Running PGUpdate|x64 interpreter...
500000 loops, best of 5: 592 nsec per loop

After:

>python -m timeit -s "from typing import SupportsIndex" "isinstance(0, SupportsIndex)"
Running PGUpdate|x64 interpreter...
1000000 loops, best of 5: 298 nsec per loop

>python -m timeit -s "from typing import SupportsIndex" "issubclass(int, SupportsIndex)"
Running PGUpdate|x64 interpreter...
500000 loops, best of 5: 523 nsec per loop

Timings done using a fresh PGO-optimised build on Windows with the main branch.

@AlexWaygood
pythongh-74690: Optimise isinstance() and issubclass() calls agai…
ec4051a 
…nst runtime-checkable protocols by avoiding costly `super()` calls
@AlexWaygood AlexWaygood added the performance Performance or resource usage label Dec 4, 2023
@AlexWaygood AlexWaygood requested a review from carljm December 4, 2023 14:17
@bedevere-app bedevere-app bot mentioned this pull request Dec 4, 2023
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For comparison, here's the timings against "normal" classes... we're still some way off 🙃 A lot closer than we were in 3.11, though.

>python -m timeit "isinstance(0, int)"
Running PGUpdate|x64 interpreter...
10000000 loops, best of 5: 27.4 nsec per loop

>python -m timeit "issubclass(str, int)"
Running PGUpdate|x64 interpreter...
10000000 loops, best of 5: 34.6 nsec per loop

@AlexWaygood AlexWaygood merged commit c718ab9 into python:main Dec 4, 2023
@AlexWaygood AlexWaygood deleted the protocol-costly-super-calls branch December 4, 2023 15:41
aisk pushed a commit to aisk/cpython that referenced this pull request Feb 11, 2024
@AlexWaygood @aisk
pythongh-74690: Optimise isinstance() and issubclass() calls agai…
78c8faf 
…nst runtime-checkable protocols by avoiding costly `super()` calls (python#112708)
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Glyphack pushed a commit to Glyphack/cpython that referenced this pull request Sep 2, 2024
@AlexWaygood @Glyphack
pythongh-74690: Optimise isinstance() and issubclass() calls agai…
cb075b6 
…nst runtime-checkable protocols by avoiding costly `super()` calls (python#112708)
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@carljm carljm carljm approved these changes

@JelleZijlstra JelleZijlstra JelleZijlstra approved these changes

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