New submission from Neil Hodgson: On Windows, non-equal comparisons (<, <=, >, >=) between strings with common prefixes are slower in Python 3.3 than 3.2. This is for both 32-bit and 64-bit builds. Performance on Linux has not decreased for the same code. The attached program tests comparisons for strings that have common prefixes.
On a 64-bit build, a 25 character string comparison is around 30% slower and a 100 character string averages 85% slower. A user of 32-bit Python builds reported the 25 character case to average 70% slower. Here are two runs of the program using 3.2/3.3 on Windows 7 on an i7 870: >c:\python32\python -u "charwidth.py" 3.2 (r32:88445, Feb 20 2011, 21:30:00) [MSC v.1500 64 bit (AMD64)] a=['C:/Users/Neil/Documents/b','C:/Users/Neil/Documents/z']176 [0.7116295577956576, 0.7055591343157613, 0.7203483026429418] a=['C:/Users/Neil/Documents/λ','C:/Users/Neil/Documents/η']176 [0.7664397841378787, 0.7199902325464409, 0.713719289812504] a=['C:/Users/Neil/Documents/b','C:/Users/Neil/Documents/η']176 [0.7341851791817691, 0.6994205901833599, 0.7106807593741005] a=['C:/Users/Neil/Documents/𠀀','C:/Users/Neil/Documents/𠀁']180 [0.7346812372666784, 0.6995411113377914, 0.7064768417728411] >c:\python33\python -u "charwidth.py" 3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 10:57:17) [MSC v.1600 64 bit (AMD64)] a=['C:/Users/Neil/Documents/b','C:/Users/Neil/Documents/z']108 [0.9913326076446045, 0.9455845241056282, 0.9459076605341776] a=['C:/Users/Neil/Documents/λ','C:/Users/Neil/Documents/η']192 [1.0472289217234318, 1.0362342484091207, 1.0197109728048384] a=['C:/Users/Neil/Documents/b','C:/Users/Neil/Documents/η']192 [1.0439643704533834, 0.9878581050301687, 0.9949265834034335] a=['C:/Users/Neil/Documents/𠀀','C:/Users/Neil/Documents/𠀁']312 [1.0987483965446412, 1.0130257167690004, 1.024832248526499] ---------- components: Unicode files: charwidth.py messages: 185824 nosy: Neil.Hodgson, ezio.melotti priority: normal severity: normal status: open title: String comparison performance regression versions: Python 3.3 Added file: http://bugs.python.org/file29652/charwidth.py _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue17615> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
