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Reduce de-optimization in BINARY_OP_INPLACE_ADD_UNICODE #91209

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sweeneyde opened this issue Mar 17, 2022 · 3 comments
Closed

Reduce de-optimization in BINARY_OP_INPLACE_ADD_UNICODE #91209

sweeneyde opened this issue Mar 17, 2022 · 3 comments
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3.11 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) performance Performance or resource usage

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@sweeneyde
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BPO 47053
Nosy @markshannon, @brandtbucher, @sweeneyde
PRs
  • bpo-47053: Reduce deoptimization in BINARY_OP_INPLACE_ADD_UNICODE #31318
  • bpo-47053: Refactor BINARY_OP_INPLACE_ADD_UNICODE #32122
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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 = None
created_at = <Date 2022-03-17.22:44:38.839>
labels = ['interpreter-core', '3.11', 'performance']
title = 'Reduce de-optimization in BINARY_OP_INPLACE_ADD_UNICODE'
updated_at = <Date 2022-03-29.02:07:19.354>
user = 'https://github.com/sweeneyde'

    bugs.python.org fields:

    activity = <Date 2022-03-29.02:07:19.354>
actor = 'Dennis Sweeney'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2022-03-17.22:44:38.839>
creator = 'Dennis Sweeney'
dependencies = []
files = []
hgrepos = []
issue_num = 47053
keywords = ['patch']
message_count = 3.0
messages = ['415455', '416008', '416238']
nosy_count = 3.0
nosy_names = ['Mark.Shannon', 'brandtbucher', 'Dennis Sweeney']
pr_nums = ['31318', '32122']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue47053'
versions = ['Python 3.11']
    @sweeneyde
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    There was a discussion here: faster-cpython/ideas#269

    Checking for whether the assignment target is the left-hand side, rather than just checking for the right refcount, is more stable and reduces the number of deoptimizations, and even increases performance on some benchmarks.

    Note that PyUnicode_Append is already a somewhat expensive function that already checks for the right reference counts, so it's fine to let as much code as possible get there, even if it will take the slow path -- we mostly just want to reduce allocations and avoid the quadratic string concatenation otherwise.

    @sweeneyde sweeneyde added type-security A security issue 3.11 only security fixes interpreter-core (Objects, Python, Grammar, and Parser dirs) performance Performance or resource usage and removed type-security A security issue labels Mar 17, 2022
    @markshannon
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    New changeset cca43b7 by Dennis Sweeney in branch 'main':
    bpo-47053: Reduce deoptimization in BINARY_OP_INPLACE_ADD_UNICODE (GH-31318)
    cca43b7

    @sweeneyde
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    New changeset 7881549 by Dennis Sweeney in branch 'main':
    bpo-47053: Refactor BINARY_OP_INPLACE_ADD_UNICODE (GH-32122)
    7881549

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