Message 382365 - Python tracker

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Author	brandtbucher
Recipients	brandtbucher, rhettinger, serhiy.storchaka, vstinner
Date	2020-12-03.02:02:03
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1606960923.31.0.257464955997.issue42536@roundup.psfhosted.org>
In-reply-to

Content
Some quick benchmarks on a normal build with CPU isolation, tuned with pyperf. No PGO/LTO. $ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass' # Current master. ......................................... Mean +- std dev: 279 ms +- 11 ms $ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass' # With above fix. ......................................... Mean +- std dev: 369 ms +- 20 ms $ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass' # With above fix (no _PyTuple_MaybeUntrack). ......................................... Mean +- std dev: 284 ms +- 17 ms $ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass' # With no tuple reuse. ......................................... Mean +- std dev: 526 ms +- 51 ms Note that this example reuses the result tuple for every iteration.

Some quick benchmarks on a normal build with CPU isolation, tuned with pyperf. No PGO/LTO.

$ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass'  # Current master.
.........................................
Mean +- std dev: 279 ms +- 11 ms

$ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass'  # With above fix.
.........................................
Mean +- std dev: 369 ms +- 20 ms

$ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass'  # With above fix (no _PyTuple_MaybeUntrack).
.........................................
Mean +- std dev: 284 ms +- 17 ms

$ ./python -m pyperf timeit --rigorous --setup 'i = (None,) * 10_000_000' 'for _, _ in zip(i, i): pass'  # With no tuple reuse.
.........................................
Mean +- std dev: 526 ms +- 51 ms

Note that this example reuses the result tuple for *every* iteration.

History
Date	User	Action	Args
2020-12-03 02:02:03	brandtbucher	set	recipients: + brandtbucher, rhettinger, vstinner, serhiy.storchaka
2020-12-03 02:02:03	brandtbucher	set	messageid: <1606960923.31.0.257464955997.issue42536@roundup.psfhosted.org>
2020-12-03 02:02:03	brandtbucher	link	issue42536 messages
2020-12-03 02:02:03	brandtbucher	create