Created on 2019-08-09 13:27 by sir-sigurd, last changed 2019-10-01 11:29 by vstinner. This issue is now closed.
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 15192 | merged | sir-sigurd, 2019-08-09 13:30 | |
| PR 16517 | merged | vstinner, 2019-10-01 11:09 | |
| Messages (4) | |||
|---|---|---|---|
| msg349285 - (view) | Author: Sergey Fedoseev (sir-sigurd) * | Date: 2019-08-09 13:27 | |
Currently PyLong_FromSize_t() uses PyLong_FromLong() for values < PyLong_BASE. It's suboptimal because PyLong_FromLong() needs to handle the sign. Removing PyLong_FromLong() call and handling small ints directly in PyLong_FromSize_t() makes it faster: $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 18.7 ns +- 0.3 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 16.7 ns +- 0.1 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 18.7 ns +- 0.3 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 16.7 ns +- 0.1 ns: 1.12x faster (-10%) $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2**10).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 26.2 ns +- 0.0 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 25.0 ns +- 0.7 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 26.2 ns +- 0.0 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 25.0 ns +- 0.7 ns: 1.05x faster (-5%) $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2**30).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 25.6 ns +- 0.1 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 25.6 ns +- 0.0 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 25.6 ns +- 0.1 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 25.6 ns +- 0.0 ns: 1.00x faster (-0%) This change makes PyLong_FromSize_t() consistently faster than PyLong_FromSsize_t(). So it might make sense to replace PyLong_FromSsize_t() with PyLong_FromSize_t() in __length_hint__() implementations and other similar cases. For example: $ python -m perf timeit -s "_len = iter(bytes(2)).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 19.4 ns +- 0.3 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 17.3 ns +- 0.1 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 19.4 ns +- 0.3 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 17.3 ns +- 0.1 ns: 1.12x faster (-11%) $ python -m perf timeit -s "_len = iter(bytes(2**10)).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 26.3 ns +- 0.1 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 25.3 ns +- 0.2 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 26.3 ns +- 0.1 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 25.3 ns +- 0.2 ns: 1.04x faster (-4%) $ python -m perf timeit -s "_len = iter(bytes(2**30)).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=10000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 27.6 ns +- 0.1 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 26.0 ns +- 0.1 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 27.6 ns +- 0.1 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 26.0 ns +- 0.1 ns: 1.06x faster (-6%) |
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| msg350446 - (view) | Author: Sergey Fedoseev (sir-sigurd) * | Date: 2019-08-25 09:58 | |
Previous benchmarks results were obtained with non-LTO build. Here are results for LTO build: $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 0).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=1000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 14.9 ns +- 0.2 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 13.1 ns +- 0.5 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 14.9 ns +- 0.2 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 13.1 ns +- 0.5 ns: 1.13x faster (-12%) $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2**10).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=1000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 22.1 ns +- 0.1 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 20.9 ns +- 0.4 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 22.1 ns +- 0.1 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 20.9 ns +- 0.4 ns: 1.05x faster (-5%) $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2**30).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=1000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 23.3 ns +- 0.0 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 21.6 ns +- 0.1 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 23.3 ns +- 0.0 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 21.6 ns +- 0.1 ns: 1.08x faster (-8%) $ python -m perf timeit -s "from itertools import repeat; _len = repeat(None, 2**60).__length_hint__" "_len()" --compare-to=../cpython-master/venv/bin/python --duplicate=1000 /home/sergey/tmp/cpython-master/venv/bin/python: ..................... 24.4 ns +- 0.1 ns /home/sergey/tmp/cpython-dev/venv/bin/python: ..................... 22.7 ns +- 0.1 ns Mean +- std dev: [/home/sergey/tmp/cpython-master/venv/bin/python] 24.4 ns +- 0.1 ns -> [/home/sergey/tmp/cpython-dev/venv/bin/python] 22.7 ns +- 0.1 ns: 1.08x faster (-7%) |
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| msg352184 - (view) | Author: Gregory P. Smith (gregory.p.smith) *  |
Date: 2019-09-12 14:41 | |
New changeset c6734ee7c55add5fdc2c821729ed5f67e237a096 by Gregory P. Smith (Sergey Fedoseev) in branch 'master': bpo-37802: Slightly improve perfomance of PyLong_FromUnsigned*() (GH-15192) https://github.com/python/cpython/commit/c6734ee7c55add5fdc2c821729ed5f67e237a096 |
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| msg353675 - (view) | Author: STINNER Victor (vstinner) * |
Date: 2019-10-01 11:29 | |
New changeset 6314abcc08f5d0f3d3a915dc9455ea223fa65517 by Victor Stinner in branch 'master': bpo-37802: Fix a compiler warning in longobject.c (GH-16517) https://github.com/python/cpython/commit/6314abcc08f5d0f3d3a915dc9455ea223fa65517 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2019-10-01 11:29:56 | vstinner | set | nosy:
+ vstinner messages: + msg353675 |
| 2019-10-01 11:09:51 | vstinner | set | pull_requests: + pull_request16107 |
| 2019-09-12 14:42:39 | gregory.p.smith | set | status: open -> closed resolution: fixed stage: patch review -> commit review |
| 2019-09-12 14:41:17 | gregory.p.smith | set | nosy:
+ gregory.p.smith messages: + msg352184 |
| 2019-08-25 09:58:32 | sir-sigurd | set | messages: + msg350446 |
| 2019-08-10 21:34:14 | Greg Price | set | nosy:
+ Greg Price |
| 2019-08-09 13:30:05 | sir-sigurd | set | keywords:
+ patch stage: patch review pull_requests: + pull_request14924 |
| 2019-08-09 13:27:40 | sir-sigurd | create | |