New submission from Xiang Zhang <[email protected]>:
Recently we update our environment from Python2.7.5 to Python2.7.13. Then one
process's CPU usage grow from 15% to 70%. The cause is
urllib.proxy_bypass_environment, the commit I wrote in #26864. Our environments
get a no_proxy environment variable which contains 4000+ items. See the
performance difference:
cascading-controller:~ # time python2 -c 'import urllib;
urllib.proxy_bypass_environment("1.1.1.1")'
real 0m1.134s
user 0m1.126s
sys 0m0.007s
cascading-controller:~ # time python2 -c 'import urllib;
urllib.proxy_bypass_environment("1.1.1.1")'
real 0m0.037s
user 0m0.024s
sys 0m0.013s
Temporarily I increased regex cache size to 6000 and the CPU usage and time
return to a reasonable range.
----------
components: Library (Lib)
messages: 308924
nosy: xiang.zhang
priority: normal
severity: normal
status: open
title: Performance regression in urllib.proxy_bypass_environment
type: performance
versions: Python 2.7, Python 3.6, Python 3.7, Python 3.8
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Python tracker <[email protected]>
<https://bugs.python.org/issue32408>
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