[issue5176] Special-case string formatting in BINARY_MODULO implementation
Collin Winter coll...@gmail.com added the comment: Committed as r69811. -- resolution: - accepted status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5176] Special-case string formatting in BINARY_MODULO implementation
Jeffrey Yasskin jyass...@gmail.com added the comment: Looks good to me. ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5176] Special-case string formatting in BINARY_MODULO implementation
Collin Winter coll...@gmail.com added the comment: Updated the patch to use only PyString_CheckExact(); added a test for the behaviour of string subclasses wrt the % operator. There's a very slight performance hit when using % with numbers, but it's so small as to be statistically insignificant. If it turns out to be relevant in the future, it's easy enough to add a special case for ints/longs. For some reason, using PyString_CheckExact instead of PyString_CheckExact || PyString_Check actually results in slower code (still an improvement, but not as much). The weird thing is that none of the benchmarks I'm running use % on string subclasses at any point. I talked about it with some of the gcc guys, but they didn't have any immediate leads. I'm going to send them the .o files in case gcc is missing some optimization. New benchmark numbers: Spitfire: Min: 0.687 - 0.668: 2.96% faster Avg: 0.689 - 0.669: 2.96% faster 2to3: Min: 20.376 - 20.187: 0.94% faster Avg: 20.396 - 20.225: 0.84% faster Django: Min: 0.560 - 0.549: 1.94% faster Avg: 0.562 - 0.552: 1.93% faster SlowPickle: Min: 0.920 - 0.905: 1.62% faster Avg: 0.926 - 0.913: 1.38% faster Added file: http://bugs.python.org/file13077/faster_modulo.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5176] Special-case string formatting in BINARY_MODULO implementation
Changes by Collin Winter coll...@gmail.com: Removed file: http://bugs.python.org/file12962/faster_modulo.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5176] Special-case string formatting in BINARY_MODULO implementation
New submission from Collin Winter coll...@gmail.com: This patch speeds up the string formatting % operator by avoiding the unnecessary indirection in PyNumber_Remainder(). This particularly benefits templating systems that do a lot of string formatting via %. Performance tested with gcc 4.3.1 x86_64 on Linux 2.6.18: 2to3: Min: 22.443 - 22.306: 0.61% faster Avg: 22.465 - 22.324: 0.63% faster Django: Min: 0.598 - 0.591: 1.24% faster Avg: 0.601 - 0.595: 1.03% faster Spitfire [1]: Min: 0.752 - 0.717: 4.91% faster Avg: 0.754 - 0.719: 4.83% faster The Django test renders a 150x150 cell table 100 times. The Spitfire test renders a 1000x1000 cell table 100 times. The 2to3 test translates all of 2to3 with `-f all` five times. There is no significant impact on PyBench. Less important code like the pure-Python pickle implementation also shows an improvement: Pickling: Min: 6.680 - 6.535: 2.22% faster Avg: 6.740 - 6.576: 2.50% faster This is pickling a list of 4 dicts 100 times. This does not impact unpickling. About the patch: I tested various combinations of PyString_Check and PyString_CheckExact and what you see in the patch demonstrated the best performance across all benchmarks. I also tested changing the definition of PyString_Check to include a short-circuit on PyString_CheckExact, but that did not provide a consistent benefit. [1] - http://code.google.com/p/spitfire/ -- assignee: jyasskin components: Interpreter Core files: faster_modulo.patch keywords: needs review, patch, patch messages: 81319 nosy: collinwinter, jyasskin severity: normal status: open title: Special-case string formatting in BINARY_MODULO implementation type: performance versions: Python 2.7 Added file: http://bugs.python.org/file12962/faster_modulo.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue5176] Special-case string formatting in BINARY_MODULO implementation
Jeffrey Yasskin jyass...@gmail.com added the comment: I think this is only valid when PyString_CheckExact is true. A subclass could override __mod__, right? I'm somewhat interested to see how a primarily-numeric benchmark responds to this patch. I'd expect it to get very slightly slower for % operations. Probably, given that there's an indirect call in the way, the extra test would hide in the noise, but it's worth checking. What's a good numeric benchmark suite? `time ./python Lib/test/test_decimal.py`? ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue5176 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
