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Created on 2019-10-30 09:29 by serhiy.storchaka, last changed 2022-04-11 14:59 by admin. This issue is now closed.
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 16991 | merged | serhiy.storchaka, 2019-10-30 09:33 | |
| Messages (2) | |||
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| msg355699 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) *  |
Date: 2019-10-30 09:29 | |
Currently math.floor(), math.ceil() and math.trunc() look up special methods __floor__, __ceil__ and __trunc__ correspondingly and execute them if found. Otherwise they execute common code for floats. There are no special slots for these methods, so looking up these names in type dicts takes some time. It is a waste of time for most common case -- float objects. The proposed PR adds checks PyFloat_CheckExact() before looking up the special method. Some microbenchmarks: $ ./python -m pyperf timeit -s "from math import floor" --duplicate 100 "floor(12345.6)" Before: Mean +- std dev: 63.2 ns +- 1.7 ns After: Mean +- std dev: 51.8 ns +- 1.3 ns $ ./python -m pyperf timeit -s "from math import ceil" --duplicate 100 "ceil(12345.6)" Before: Mean +- std dev: 61.1 ns +- 1.5 ns After: Mean +- std dev: 51.9 ns +- 1.1 ns $ ./python -m pyperf timeit -s "from math import trunc" --duplicate 100 "trunc(12345.6)" Before: Mean +- std dev: 72.0 ns +- 1.5 ns After: Mean +- std dev: 34.7 ns +- 1.4 ns We should also check how this optimization affects other types: $ ./python -m pyperf timeit -s "from math import floor" --duplicate 100 "floor(12345)" Before: Mean +- std dev: 56.3 ns +- 1.3 ns After: Mean +- std dev: 56.3 ns +- 1.4 ns $ ./python -m pyperf timeit -s "from math import ceil" --duplicate 100 "ceil(12345)" Before: Mean +- std dev: 55.7 ns +- 1.6 ns After: Mean +- std dev: 56.8 ns +- 1.6 ns $ ./python -m pyperf timeit -s "from math import trunc" --duplicate 100 "trunc(12345)" Before: Mean +- std dev: 54.7 ns +- 1.3 ns After: Mean +- std dev: 56.7 ns +- 1.5 ns |
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| msg356753 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2019-11-16 16:01 | |
New changeset 5fd5cb8d85fab3393dd76c7f3de1cdeb8ecf7203 by Serhiy Storchaka in branch 'master': bpo-38639: Optimize floor(), ceil() and trunc() for floats. (GH-16991) https://github.com/python/cpython/commit/5fd5cb8d85fab3393dd76c7f3de1cdeb8ecf7203 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:59:22 | admin | set | github: 82820 |
| 2019-11-16 17:23:10 | serhiy.storchaka | set | status: open -> closed resolution: fixed stage: patch review -> resolved |
| 2019-11-16 16:01:02 | serhiy.storchaka | set | messages: + msg356753 |
| 2019-10-30 09:33:44 | serhiy.storchaka | set | keywords:
+ patch stage: patch review pull_requests: + pull_request16517 |
| 2019-10-30 09:30:46 | serhiy.storchaka | set | title: Optimize floor() and ceil() for floats -> Optimize floor(), ceil() and trunc() for floats |
| 2019-10-30 09:29:36 | serhiy.storchaka | create | |