gh-144380: Fix incorrect type check in buffered_iternext()
#144381
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colesbury
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needs backport to 3.13
The condition used Py_IS_TYPE(tp, ...) where tp is already a `type`, this made the fast path unreachable. Avoid unnecessary method resolution checks in the iteration hot path, resulting in ~49% faster line iteration for `io.BufferedReader`.
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Thanks, new entry added |
cmaloney
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kumaraditya303
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Thanks @ruiyangke for the PR, and @kumaraditya303 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14. |
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…ythonGH-144381) (cherry picked from commit 40d07cad38bf3ce60f4ca03f1836e8650fe40df5) Co-authored-by: Ruiyang Ke <me@ry.ke>
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…ythonGH-144381) (cherry picked from commit 40d07ca) Co-authored-by: Ruiyang Ke <me@ry.ke>
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GH-144389 is a backport of this pull request to the 3.14 branch. |
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GH-144390 is a backport of this pull request to the 3.13 branch. |
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Fix incorrect type check in
buffered_iternext()that prevented the fast path from ever being taken, slowing down iteration over buffered binary files.Since
tpis already a type object,Py_IS_TYPE(tp, X)expands toPy_TYPE(tp) == X, which compares thetypeitself againstBufferedReader. This is always false, so the fast path was never taken.pyperf benchmark:
Closes: #144380
buffered_iternextis never taken due to incorrect type check #144380