[New-bugs-announce] [issue13623] Bytes performance regression in python3.3 vs python3.2

[Boris FELD]

New submission from Boris FELD <lothiraldan at gmail.com>:

Hello everyone, I juste tried to launch the stringbench on python3.2 and python3.3 dev versions and some bytes tests run slower in python3.3 than in python3.2.

I cc the two raw output of both runs. I also extracted most interesting data (all the tests with more than 20% of performance regression):
- (b"A"*1000).rfind(b"A") (*1000): -70.103093%
- (b"A"*1000).find(b"B") (*1000): -48.372093%
- (b"A"*1000).rindex(b"A") (*1000): -68.888889%
- s=b"ABC"*33; (s+b"E"+(b"D"+s)*500).rfind(s+b"E") (*100): -28.982301%
- (b"C"+b"AB"*300).rfind(b"CA") (*1000): -29.565217%
- (b"AB"*1000).index(b"AB") (*1000): -68.539326%
- b"Andrew".endswith(b"w") (*1000): -21.212121%
- (b"A"*1000).index(b"A") (*1000): -71.111111%
- (b"BC"+b"AB"*300).rfind(b"BC") (*1000): -42.788462%
- b"Andrew".startswith(b"Andrew") (*1000): -20.588235%
- (b"AB"*1000).find(b"AB") (*1000): -69.318182%
- (b"AB"*1000).rfind(b"AB") (*1000): -69.791667%
- (b"A"*1000).rfind(b"B") (*1000): -37.988827%
- (b"AB"*300+"C").index(b"BC") (*1000): -28.750000%
- b"B" in b"A"*1000 (*1000): -24.479167%
- (b"AB"*300+"CA").find(b"CA") (*1000): -33.673469%
- (b"AB"*1000).rindex(b"AB") (*1000): -67.777778%
- (b"C"+"AB"*300).rindex(b"CA") (*1000): -29.017857%
- (b"AB"*300+"C").find(b"BC") (*1000): -28.451883%
- b"Andrew".startswith(b"A") (*1000): -21.212121%
- b"Andrew".startswith(b"Anders") (*1000): -21.212121%
- (b"A"*1000).partition(b"B") (*1000): -30.656934%
- (b"AB"*1000).rfind(b"CA") (*1000): -20.603015%
- (b"AB"*1000).rfind(b"BC") (*1000): -35.645472%
- (b"A"*1000).find(b"A") (*1000): -70.454545%

My environment is:
Mac OS X 10.6.8
GCC i686-apple-darwin10-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5666) (dot 3)
CPython3.3 revision ea421c534305
CPython3.2 revision 0b86da9d6964

----------
assignee: collinwinter
components: Benchmarks
files: stringbench_log_cpython3.2
messages: 149689
nosy: Boris.FELD, collinwinter
priority: normal
severity: normal
status: open
title: Bytes performance regression in python3.3 vs python3.2
type: performance
versions: Python 3.2, Python 3.3
Added file: http://bugs.python.org/file23999/stringbench_log_cpython3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue13623>
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