[issue42160] unnecessary overhead in tempfile

Change by STINNER Victor : -- nosy: -vstinner ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue42160] unnecessary overhead in tempfile

Change by Inada Naoki : -- pull_requests: +21987 pull_request: https://github.com/python/cpython/pull/23068 ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

Serhiy Storchaka added the comment: I have tested my idea, such optimization speeds up _RandomNameSequence by 16%. At the cost of more complex code. It is not worth. -- resolution: -> rejected stage: patch review -> resolved status: open -> closed

[issue42160] unnecessary overhead in tempfile

Eric Wolf added the comment: >>> timeit(os.getpid) 0.0899073329931 Considering the reference leaks, os.getpid() seems to be the better solution. -- ___ Python tracker

[issue42160] unnecessary overhead in tempfile

Serhiy Storchaka added the comment: Instead of os.getpid() we can use a global variable, and the single callback can reset it. But is it worth? Is os.getpid() so slow? -- ___ Python tracker

[issue42160] unnecessary overhead in tempfile

Eric Wolf added the comment: It would be possible to allow the GC to finalize the Random instances through weak references. On the other hand, if many _RandomNameSequence instances were used temporarily, a lot of callbacks would be registered via os.register_at_fork(), could that cause

[issue42160] unnecessary overhead in tempfile

Serhiy Storchaka added the comment: See also issue30030. -- nosy: +serhiy.storchaka ___ Python tracker ___ ___ Python-bugs-list

[issue42160] unnecessary overhead in tempfile

Inada Naoki added the comment: @Deric-W Please create another PR to change from `choise` to `choises` if you want to optimize it. -- ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

Inada Naoki added the comment: New changeset 43ca084c88d1e46a44199f347c72e26db84903c9 by Inada Naoki in branch 'master': Revert "bpo-42160: tempfile: Reduce overhead of pid check. (GH-22997)" https://github.com/python/cpython/commit/43ca084c88d1e46a44199f347c72e26db84903c9 --

[issue42160] unnecessary overhead in tempfile

Change by Inada Naoki : -- pull_requests: +21974 stage: resolved -> patch review pull_request: https://github.com/python/cpython/pull/23055 ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

Inada Naoki added the comment: Oh, _RandomNameSequence is not true singleton. Instance is used in tests actually. Using `os.register_at_fork` was but idea. Let's reject it. -- ___ Python tracker

[issue42160] unnecessary overhead in tempfile

STINNER Victor added the comment: The commit 8e409cebad42032bb7d0f2cadd8b1e36081d98af introduced a reference leak: https://buildbot.python.org/all/#/builders/320/builds/71 $ make && ./python -m test test_tempfile -R 3:3 ... test_tempfile leaked [49, 49, 49] references, sum=147 test_tempfile

[issue42160] unnecessary overhead in tempfile

Eric Wolf added the comment: Thanks -- ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue42160] unnecessary overhead in tempfile

Inada Naoki added the comment: Thanks -- resolution: -> fixed stage: patch review -> resolved status: open -> closed versions: +Python 3.10 -Python 3.6, Python 3.7, Python 3.8, Python 3.9 ___ Python tracker

[issue42160] unnecessary overhead in tempfile

Inada Naoki added the comment: New changeset 8e409cebad42032bb7d0f2cadd8b1e36081d98af by Eric W in branch 'master': bpo-42160: tempfile: Reduce overhead of pid check. (GH-22997) https://github.com/python/cpython/commit/8e409cebad42032bb7d0f2cadd8b1e36081d98af -- nosy: +methane

[issue42160] unnecessary overhead in tempfile

Eric Wolf added the comment: It seems to be insignificant, however it would allow for easier monkey-patching: https://bugs.python.org/issue32276 Instead of changing _Random one could simply assign a new instance to _named_sequence -- ___ Python

[issue42160] unnecessary overhead in tempfile

Benjamin Peterson added the comment: I also wonder if the overhead of getpid() is actually significant for anything. -- ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

Eric Wolf added the comment: SystemRandom seems to be slower: from random import Random, SystemRandom from timeit import timeit user = Random() system = SystemRandom() characters = "abcdefghijklmnopqrstuvwxyz0123456789_" timeit(lambda: user.choice(characters)) >>> 0.5491522020020057

[issue42160] unnecessary overhead in tempfile

Benjamin Peterson added the comment: Wouldn't it be simpler to use random.SystemRandom instead? -- nosy: +benjamin.peterson ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

Change by Eric Wolf : -- keywords: +patch pull_requests: +21911 stage: -> patch review pull_request: https://github.com/python/cpython/pull/22997 ___ Python tracker ___

[issue42160] unnecessary overhead in tempfile

New submission from Eric Wolf : The tempfile module contains the class _RandomNameSequence, which has the rng property. This property checks os.getpid() every time and re-initializes a random number generator when it has changed. However, this is only necessary on systems which allow the

[issue42160] unnecessary overhead in tempfile

Change by Eric Wolf : -- components: Library (Lib) nosy: Deric-W priority: normal severity: normal status: open title: unnecessary overhead in tempfile type: enhancement versions: Python 3.6, Python 3.7, Python 3.8, Python 3.9 ___ Python tracker