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gh-74690: Optimise `isinstance()` and `issubclass()` calls against runtime-checkable protocols by avoiding costly `super()` calls by AlexWaygood · Pull Request #112708 · python/cpython · GitHub
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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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AlexWaygood merged 3 commits into
python:mainfrom
AlexWaygood:protocol-costly-super-calls
Dec 4, 2023
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gh-74690: Optimise isinstance() and issubclass() calls against runtime-checkable protocols by avoiding costly super() calls#112708
AlexWaygood merged 3 commits into
python:mainfrom
AlexWaygood:protocol-costly-super-calls

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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.

pythongh-74690: Optimise isinstance() and issubclass() calls agai… …
ec4051a
…nst runtime-checkable protocols by avoiding costly `super()` calls
AlexWaygood added the performance Performance or resource usage label Dec 4, 2023
AlexWaygood requested a review from carljm December 4, 2023 14:17
bedevere-app Bot mentioned this pull request Dec 4, 2023
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AlexWaygood commented 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 merged commit c718ab9 into python:main Dec 4, 2023
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
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
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 approved these changes
JelleZijlstra JelleZijlstra approved these changes

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