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Optimize parsing of regular expressions #63579

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serhiy-storchaka opened this issue Oct 24, 2013 · 13 comments
Closed

Optimize parsing of regular expressions #63579

serhiy-storchaka opened this issue Oct 24, 2013 · 13 comments
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expert-regex performance Performance or resource usage stdlib Python modules in the Lib dir

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@serhiy-storchaka
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serhiy-storchaka commented Oct 24, 2013

BPO 19380
Nosy @pitrou, @vstinner, @ezio-melotti, @serhiy-storchaka, @MojoVampire
Files
  • re_parse.patch
  • re_parse_2.patch
  • re_parse_3.patch
  • re_parse_4.patch
  • re_parse_5.patch
  • 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 = 'https://github.com/serhiy-storchaka'
    closed_at = <Date 2014-10-10.08:46:47.543>
    created_at = <Date 2013-10-24.20:14:19.696>
    labels = ['expert-regex', 'library', 'performance']
    title = 'Optimize parsing of regular expressions'
    updated_at = <Date 2014-10-10.08:46:47.541>
    user = 'https://github.com/serhiy-storchaka'

    bugs.python.org fields:

    activity = <Date 2014-10-10.08:46:47.541>
    actor = 'serhiy.storchaka'
    assignee = 'serhiy.storchaka'
    closed = True
    closed_date = <Date 2014-10-10.08:46:47.543>
    closer = 'serhiy.storchaka'
    components = ['Library (Lib)', 'Regular Expressions']
    creation = <Date 2013-10-24.20:14:19.696>
    creator = 'serhiy.storchaka'
    dependencies = []
    files = ['32341', '32343', '36649', '36818', '36843']
    hgrepos = []
    issue_num = 19380
    keywords = ['patch', 'needs review']
    message_count = 13.0
    messages = ['201177', '201183', '201191', '201192', '201227', '206557', '227032', '227041', '227053', '228605', '228838', '228964', '228971']
    nosy_count = 7.0
    nosy_names = ['pitrou', 'vstinner', 'ezio.melotti', 'mrabarnett', 'python-dev', 'serhiy.storchaka', 'josh.r']
    pr_nums = []
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'performance'
    url = 'https://bugs.python.org/issue19380'
    versions = ['Python 3.5']

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 24, 2013

    Proposed patch optimizes parsing of regular expressions. Total time of re unittests decreased by 10%.

    @serhiy-storchaka serhiy-storchaka self-assigned this Oct 24, 2013
    @serhiy-storchaka serhiy-storchaka added stdlib Python modules in the Lib dir expert-regex performance Performance or resource usage labels Oct 24, 2013
    @pitrou
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    pitrou commented Oct 24, 2013

    I don't think "+=" speeds up anything for ints, you might as well minimize code churn by avoiding such changes.

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 24, 2013

    Done.

    @pitrou
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    pitrou commented Oct 24, 2013

    Do you have any benchmark figures (apart from the time of re unittests)?

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 25, 2013

    ### regex_compile ###
    Min: 2.897919 -> 2.577488: 1.12x faster
    Avg: 3.066306 -> 2.681966: 1.14x faster
    Significant (t=26.77)
    Stddev: 0.08789 -> 0.05085: 1.7283x smaller

    @serhiy-storchaka
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    serhiy-storchaka commented Dec 18, 2013

    Could someone please make a review?

    @serhiy-storchaka
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    serhiy-storchaka commented Sep 18, 2014

    Actually "if x:" is slightly faster than "if x is not None:" on current implementation.

    @pitrou
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    pitrou commented Sep 18, 2014

    "is not None" is more readable, though. When using plain boolean testing, it's never obvious whether you can have a zero-length string, a null number, etc.

    @serhiy-storchaka
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    serhiy-storchaka commented Sep 18, 2014

    Well, then please look at re_parse_2.patch (it is still applied cleanly).

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 5, 2014

    Here is a patch which addresses Yury's and Josh's comments. Also discarded few minor changes.

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 9, 2014

    Updated patch implements Antoine's suggestions.

    @python-dev
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    python-dev mannequin commented Oct 10, 2014

    New changeset 1adeac2a8714 by Serhiy Storchaka in branch 'default':
    Issue bpo-19380: Optimized parsing of regular expressions.
    https://hg.python.org/cpython/rev/1adeac2a8714

    @serhiy-storchaka
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    serhiy-storchaka commented Oct 10, 2014

    Thank you for your reviews Yury, Josh, and Antoine.

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