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Faster positional arguments parsing in PyArg_ParseTupleAndKeywords #73215

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Faster positional arguments parsing in PyArg_ParseTupleAndKeywords#73215
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3.7 (EOL)end of lifeinterpreter-core(Objects, Python, Grammar, and Parser dirs)performancePerformance or resource usage

Description

@serhiy-storchaka
serhiy-storchaka
opened on Dec 20, 2016
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']

    Activity

    1. serhiy-storchaka commented on Dec 20, 2016

      @serhiy-storchaka
      serhiy-storchaka
      on Dec 20, 2016
      MemberAuthor

      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.

    2. serhiy-storchaka
      added
      3.7 (EOL)end of life
      interpreter-core(Objects, Python, Grammar, and Parser dirs)
      performancePerformance or resource usage
      on Dec 20, 2016

    3. methane commented on Jan 15, 2017

      @methane
      methane
      on Jan 15, 2017
      Member

      LGTM

    4. python-dev commented on Jan 16, 2017

      @python-dev
      python-devmannequin
      on Jan 16, 2017
      Mannequin

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

    5. vstinner commented on Jan 16, 2017

      @vstinner
      vstinner
      on Jan 16, 2017
      Member

      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.

    6. vstinner commented on Jan 16, 2017

      @vstinner
      vstinner
      on Jan 16, 2017
      Member

      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?

    7. methane commented on Jan 17, 2017

      @methane
      methane
      on Jan 17, 2017
      Member

      LGTM again.

    8. python-dev commented on Jan 17, 2017

      @python-dev
      python-devmannequin
      on Jan 17, 2017
      Mannequin

      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

    9. serhiy-storchaka commented on Jan 17, 2017

      @serhiy-storchaka
      serhiy-storchaka
      on Jan 17, 2017
      MemberAuthor

      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.

    10. serhiy-storchaka
      closed this as completedon Jan 17, 2017
    11. ezio-melotti
      transferred this issue fromon Apr 10, 2022
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