[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

Inada Naoki  added the comment:


New changeset 6cbc84fb99acb33dd659d7adb29a20adbe62b74a by Inada Naoki in branch 
'master':
bpo-38613: Optimize set operations of dict keys. (GH-16961)
https://github.com/python/cpython/commit/6cbc84fb99acb33dd659d7adb29a20adbe62b74a


--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

Change by Inada Naoki :


--
resolution:  -> fixed
stage: patch review -> resolved
status: open -> closed

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

Inada Naoki  added the comment:

done.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Raymond Hettinger]

Raymond Hettinger  added the comment:

Consider testing PyDict_CheckExact.

--
nosy: +rhettinger

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Serhiy Storchaka]

Serhiy Storchaka  added the comment:

But what if a dict subclass overrides __iter__? You can get different result if 
set(d) != set(d.keys()).

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

Inada Naoki  added the comment:

> How does it work with dict subclasses?

PySet_New(iterable) uses fast path only when `PyDict_CheckExact(iterable)` is 
true.

So there is no change for dict subclasses.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Serhiy Storchaka]

Serhiy Storchaka  added the comment:

How does it work with dict subclasses?

--
nosy: +serhiy.storchaka

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

Change by Inada Naoki :


--
keywords: +patch
pull_requests: +16489
stage:  -> patch review
pull_request: https://github.com/python/cpython/pull/16961

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue38613] Optimize some set operations in dictkeys object

[Inada Naoki]

New submission from Inada Naoki :

-, |, and ^ of dictkeys are implemented as:

PyObject *result = PySet_New(self);
// Call set.difference_update, set.update, set.symmetric_difference_update with 
other.

PySet_New(iterable) has optimized step for iterable is dict.
But since iterable is dictkeys, PyIter_Next() is called for all elements in the 
dict.

We can pass dict instead of dictkey object to PySet_New.

  $ ./python -m pyperf timeit -o patched.json -s 'k = 
dict.fromkeys("abcdefghijklmnopqrstuvwxyz").keys(); s={1,2,3}' -- 'k | {1,2,3}'
  $ ./python -m pyperf compare_to master.json patched.json
  Mean +- std dev: [master] 778 ns +- 17 ns -> [patched] 550 ns +- 24 ns: 1.42x 
faster (-29%)

--
components: Interpreter Core
messages: 355536
nosy: inada.naoki
priority: normal
severity: normal
status: open
title: Optimize some set operations in dictkeys object
type: performance
versions: Python 3.9

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com