[issue39425] list.count performance regression

Change by Maxwell Bernstein : -- nosy: +tekknolagi nosy_count: 5.0 -> 6.0 pull_requests: +28262 pull_request: https://github.com/python/cpython/pull/30036 ___ Python tracker __

[issue39425] list.count performance regression

Change by STINNER Victor : -- pull_requests: +17516 pull_request: https://github.com/python/cpython/pull/18130 ___ Python tracker ___ __

[issue39425] list.count performance regression

Pablo Galindo Salgado added the comment: > The following result is a little bit surprising: haha, I went to exactly the same journey when reviewing this PR :) -- ___ Python tracker _

[issue39425] list.count performance regression

STINNER Victor added the comment: > In fact, PyObject_RichCompareBool() has a fast path if the two object > pointers are equal It's documented: https://docs.python.org/dev/c-api/object.html?highlight=pyobject_richcomparebool#c.PyObject_RichCompareBool -- ___

[issue39425] list.count performance regression

STINNER Victor added the comment: The following result is a little bit surprising: >>> nan=float("nan"); ([nan]*5).count(nan) 5 >>> nan == nan False But in fact, the optimization doesn't change the value. It was already 5 previously. In fact, PyObject_RichCompareBool() has a fast path if th

[issue39425] list.count performance regression

Pablo Galindo Salgado added the comment: New changeset 9e06d61af30bac4fcacb7973f826147ccc010392 by Pablo Galindo (Miss Islington (bot)) in branch '3.7': bpo-39425: Fix list.count performance regression (GH-18119) (GH-18121) https://github.com/python/cpython/commit/9e06d61af30bac4fcacb7973f826

[issue39425] list.count performance regression

Pablo Galindo Salgado added the comment: Thanks for the PR, Dong-hee Na :) -- resolution: -> fixed stage: patch review -> resolved status: open -> closed ___ Python tracker _

[issue39425] list.count performance regression

Pablo Galindo Salgado added the comment: New changeset fdb21609d944941f0732df72dc3d07a7a9a7efea by Pablo Galindo (Miss Islington (bot)) in branch '3.8': bpo-39425: Fix list.count performance regression (GH-18119) (GH-18120) https://github.com/python/cpython/commit/fdb21609d944941f0732df72dc3d

[issue39425] list.count performance regression

Change by miss-islington : -- pull_requests: +17507 pull_request: https://github.com/python/cpython/pull/18120 ___ Python tracker ___ __

[issue39425] list.count performance regression

miss-islington added the comment: New changeset 14d80d0b605d8b148e14458e4c1853a940071462 by Miss Islington (bot) (Dong-hee Na) in branch 'master': bpo-39425: Fix list.count performance regression (GH-18119) https://github.com/python/cpython/commit/14d80d0b605d8b148e14458e4c1853a940071462 --

[issue39425] list.count performance regression

Change by miss-islington : -- pull_requests: +17508 pull_request: https://github.com/python/cpython/pull/18121 ___ Python tracker ___ __

[issue39425] list.count performance regression

Change by Dong-hee Na : -- versions: +Python 3.7 ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail

[issue39425] list.count performance regression

Change by Dong-hee Na : -- nosy: +inada.naoki, pablogsal, vstinner ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscr

[issue39425] list.count performance regression

Change by Dong-hee Na : -- keywords: +patch pull_requests: +17506 stage: -> patch review pull_request: https://github.com/python/cpython/pull/18119 ___ Python tracker ___

[issue39425] list.count performance regression

New submission from Dong-hee Na : ./python.exe -m pyperf timeit -s 'a = [1]*100' 'a.count(1)' Current Master: Mean +- std dev: 1.05 us +- 0.03 us My patch: Mean +- std dev: 423 ns +- 11 ns This is the side-effect of pr 17022. -- assignee: corona10 messages: 360488 nosy: corona10 prio