[issue18594] C accelerator for collections.Counter is slow

Roundup Robot added the comment: New changeset e4cec1116e5c by Raymond Hettinger in branch '3.3': Issue #18594: Make the C code more closely match the pure python code. http://hg.python.org/cpython/rev/e4cec1116e5c -- ___ Python tracker

[issue18594] C accelerator for collections.Counter is slow

Changes by Raymond Hettinger : -- resolution: -> fixed status: open -> closed ___ Python tracker ___ ___ Python-bugs-list mailing lis

[issue18594] C accelerator for collections.Counter is slow

Roundup Robot added the comment: New changeset 1ee6f8a96fb9 by Raymond Hettinger in branch '3.3': Issue #18594: Fix the fallback path in collections.Counter(). http://hg.python.org/cpython/rev/1ee6f8a96fb9 -- ___ Python tracker

[issue18594] C accelerator for collections.Counter is slow

Stefan Behnel added the comment: Can you update the benchmark numbers to show what the difference is compared to pure Python (and to the fastpath) now? One more thing: the fastpath depends on .__getitem__() and friends, whereas the fallback path depends on .get(). What if someone overrides .ge

[issue18594] C accelerator for collections.Counter is slow

Raymond Hettinger added the comment: Attaching a patch for the slow path. Makes the code exactly match the pure python version. This kicks in whether someone has subclassed Counter and overridden either __getitem__ or __setitem__. -- Added file: http://bugs.python.org/file31932/fix_c

[issue18594] C accelerator for collections.Counter is slow

Roundup Robot added the comment: New changeset 6aef095fdb30 by Raymond Hettinger in branch '3.3': Issue #18594: Fix the fast path for collections.Counter(). http://hg.python.org/cpython/rev/6aef095fdb30 -- nosy: +python-dev ___ Python tracker

[issue18594] C accelerator for collections.Counter is slow

Serhiy Storchaka added the comment: Benchmarking results look great. But isn't _PyObject_LookupSpecial() more appropriate function for special methods lookup than PyObject_GetAttrString()? -- ___ Python tracker _

[issue18594] C accelerator for collections.Counter is slow

Stefan Behnel added the comment: Patch LGTM and seems to work well, according to your numbers. Only minor nitpick would be that the method references could be decref-ed earlier, but that would complicate the code a bit. -- ___ Python tracker

[issue18594] C accelerator for collections.Counter is slow

Raymond Hettinger added the comment: Repaired version $ py -m timeit -s 'from random import seed, randrange; seed(8675309); data=[randrange(1000) for i in range(10)]; from collections import Counter' 'Counter(data)' 100 loops, best of 3: 14.3 msec per loop $ py -m timeit -

[issue18594] C accelerator for collections.Counter is slow

Changes by Raymond Hettinger : Removed file: http://bugs.python.org/file31917/fix_counter.diff ___ Python tracker ___ ___ Python-bugs-list mai

[issue18594] C accelerator for collections.Counter is slow

Changes by Raymond Hettinger : Added file: http://bugs.python.org/file31918/fix_counter.diff ___ Python tracker ___ ___ Python-bugs-list maili

[issue18594] C accelerator for collections.Counter is slow

Changes by Raymond Hettinger : -- stage: needs patch -> patch review Added file: http://bugs.python.org/file31917/fix_counter.diff ___ Python tracker ___

[issue18594] C accelerator for collections.Counter is slow

Raymond Hettinger added the comment: A C-accelerator should ALWAYS be able to beat a pure python version if it does the same steps but without the overhead of the eval-loop. And in special cases such as type(self)==Counter, it can do much better. To resolve this report, the C accelerator need

[issue18594] C accelerator for collections.Counter is slow

Changes by Raymond Hettinger : -- assignee: -> rhettinger priority: high -> normal ___ Python tracker ___ ___ Python-bugs-list mailin

[issue18594] C accelerator for collections.Counter is slow

Changes by Eli Bendersky : -- nosy: -eli.bendersky ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://mai

[issue18594] C accelerator for collections.Counter is slow

Anoop Thomas Mathew added the comment: Performance comparison with and without patch applied. -- Added file: http://bugs.python.org/file31775/performance_comparision.csv ___ Python tracker _

[issue18594] C accelerator for collections.Counter is slow

Anoop Thomas Mathew added the comment: 40% faster collections.Counter() . Removed C accelerator. Patch attached. Passes all tests. Results comparison follows. -- keywords: +patch nosy: +Anoop.Thomas.Mathew Added file: http://bugs.python.org/file31774/collections_Counter_without_C_accel

[issue18594] C accelerator for collections.Counter is slow

Changes by Phil Connell : -- nosy: +pconnell ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python

[issue18594] C accelerator for collections.Counter is slow

Changes by Jesús Cea Avión : -- nosy: +jcea ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.

[issue18594] C accelerator for collections.Counter is slow

Eli Bendersky added the comment: That sounds like a good idea, Stefan. -- nosy: +eli.bendersky ___ Python tracker ___ ___ Python-bugs-

[issue18594] C accelerator for collections.Counter is slow

Serhiy Storchaka added the comment: Are there any cases where the counter class with the C accelerator is faster than the pure Python version? Here is a benchmarking script (modification of Roy Smith's script [1]) and looks as the pure Python version is faster even for data that has not many u

[issue18594] C accelerator for collections.Counter is slow

Changes by Antoine Pitrou : -- nosy: +rhettinger priority: normal -> high ___ Python tracker ___ ___ Python-bugs-list mailing list Uns

[issue18594] C accelerator for collections.Counter is slow

New submission from Stefan Behnel: The C accelerator for the collections.Counter class (_count_elements() in _collections.c) is slower than the pure Python versions for data that has many unique entries. This is because the fast path for dicts is not taken (Counter is a subtype of dict) and th