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Faster positional arguments parsing in PyArg_ParseTupleAndKeywords #73215

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serhiy-storchaka opened this issue Dec 20, 2016 · 8 comments
Closed

Faster positional arguments parsing in PyArg_ParseTupleAndKeywords #73215

serhiy-storchaka opened this issue Dec 20, 2016 · 8 comments
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3.7 (EOL) end of life interpreter-core (Objects, Python, Grammar, and Parser dirs) performance Performance or resource usage

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@serhiy-storchaka
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BPO 29029
Nosy @vstinner, @methane, @serhiy-storchaka
Files
  • PyArg_ParseTupleAndKeywords-faster-positional-args-parse.patch
  • PyArg_ParseTupleAndKeywords-faster-positional-args-parse-2.patch
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    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
closed_at = <Date 2017-01-17.08:15:00.665>
created_at = <Date 2016-12-20.21:30:18.353>
labels = ['interpreter-core', '3.7', 'performance']
title = 'Faster positional arguments parsing in PyArg_ParseTupleAndKeywords'
updated_at = <Date 2017-01-17.08:15:00.664>
user = 'https://github.com/serhiy-storchaka'

    bugs.python.org fields:

    activity = <Date 2017-01-17.08:15:00.664>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = True
closed_date = <Date 2017-01-17.08:15:00.665>
closer = 'serhiy.storchaka'
components = ['Interpreter Core']
creation = <Date 2016-12-20.21:30:18.353>
creator = 'serhiy.storchaka'
dependencies = []
files = ['45977', '46307']
hgrepos = []
issue_num = 29029
keywords = ['patch']
message_count = 8.0
messages = ['283711', '285515', '285590', '285591', '285592', '285617', '285621', '285622']
nosy_count = 4.0
nosy_names = ['vstinner', 'methane', 'python-dev', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue29029'
versions = ['Python 3.7']
    @serhiy-storchaka
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    Proposed patch speeds up parsing positional arguments in PyArg_ParseTupleAndKeywords().

    $ ./python -m perf timeit "1 .to_bytes(1, 'little', signed=False)"
Unpatched:  Median +- std dev: 2.01 us +- 0.09 us
Patched:    Median +- std dev: 1.23 us +- 0.03 us

    Currently names of all passed positional argument are looked up in the kwargs dictionary for checking if the argument is passed as positional and keyword argument. With the patch this is checked only if there are unhandled keyword arguments after parsing keyword arguments that don't passed as positional arguments.

    The same optimization also is applied to _PyArg_ParseTupleAndKeywordsFast() and like, but the effect is much smaller.

    The patch also includes tiny refactoring.

    @serhiy-storchaka serhiy-storchaka added 3.7 (EOL) end of life interpreter-core (Objects, Python, Grammar, and Parser dirs) performance Performance or resource usage labels Dec 20, 2016
    @methane
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    methane commented Jan 15, 2017

    LGTM

    @python-dev
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    python-dev mannequin commented Jan 16, 2017

    New changeset a36e60c5fee0 by Victor Stinner in branch 'default':
    Rename keywords to kwargs in getargs.c
    https://hg.python.org/cpython/rev/a36e60c5fee0

    @vstinner
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    Oh, I missed this issue. Since I made minor cleanup recently, I took the liberty of rebasing your patch.

    I also pushed your "keywords => kwargs" change, just to make the patch simpler to review.

    @vstinner
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    Unpatched: Median +- std dev: 2.01 us +- 0.09 us
    Patched: Median +- std dev: 1.23 us +- 0.03 us

    Oh wow, impressive speedup! As usual, good job Serhiy ;-)

    PyArg_ParseTupleAndKeywords-faster-positional-args-parse-2.patch: LGTM! Can you please push it?

    @methane
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    methane commented Jan 17, 2017

    LGTM again.

    @python-dev
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    python-dev mannequin commented Jan 17, 2017

    New changeset a8563ef0eb8a by Serhiy Storchaka in branch 'default':
    Issue bpo-29029: Speed up processing positional arguments in
    https://hg.python.org/cpython/rev/a8563ef0eb8a

    @serhiy-storchaka
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    Thank you for your reviews Inada and Victor. Thank you for rebasing the patch Victor.

    I were going first to try an alternative patch, maybe less efficient, but allowing to share more code. But since the code is changed so fast, it is better to commit the ready patch.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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