https://bugs.exim.org/show_bug.cgi?id=2698
Bug ID: 2698
Summary: Performance regression caused by r1236
Product: PCRE
Version: 10.36 (PCRE2)
Hardware: All
OS: All
Status: NEW
Severity: bug
Priority: medium
Component: Code
Assignee: philip.ha...@gmail.com
Reporter: whi...@gentoo.org
CC: pcre-dev@exim.org
Created attachment 1369
--> https://bugs.exim.org/attachment.cgi?id=1369&action=edit
PoC (PHP script) showing the problem
Hi,
Debian updated PCRE from 10.34 to 10.36 this week which uncovered a major
performance regression in a PHP application. I was able to reproduce this on
Gentoo.
Please see the attached PHP script. I run the PoC against 10.34 and 10.36
(including current SVN trunk, i.e. it is still unfixed):
> thomas@hv-gentoo-x64 /var/tmp $ time php -d pcre.jit=0 pcre-problem.php
> PCRE version: 10.36 2020-12-04
> PCRE JIT: disabled
> Got content in 0.11089181900024s
> int(0)
>
> Finished after 122.9806330204s
>
> real 2m2.990s
> user 2m2.712s
> sys 0m0.007s
>
>
> thomas@hv-gentoo-x64 /var/tmp $ time php -d pcre.jit=1 pcre-problem.php
> PCRE version: 10.36 2020-12-04
> PCRE JIT: enabled
> Got content in 0.26398801803589s
> int(0)
>
> Finished after 12.119644880295s
>
> real 0m12.129s
> user 0m11.853s
> sys 0m0.000s
>
>
> thomas@hv-gentoo-x64 /var/tmp $ time php -d pcre.jit=0 pcre-problem.php
> PCRE version: 10.34 2019-11-21
> PCRE JIT: disabled
> Got content in 0.11802387237549s
> int(0)
>
> Finished after 120.98400783539s
>
> real 2m0.994s
> user 2m0.712s
> sys 0m0.004s
>
>
> thomas@hv-gentoo-x64 /var/tmp $ time php -d pcre.jit=1 pcre-problem.php
> PCRE version: 10.34 2019-11-21
> PCRE JIT: enabled
> Got content in 0.11507105827332s
> int(0)
>
> Finished after 0.11547303199768s
>
> real 0m0.125s
> user 0m0.005s
> sys 0m0.008s
I run this on a modern CPU with 4.2GHz single thread performance.
A bisect revealed https://vcs.pcre.org/pcre2?view=revision&revision=1236 as bad
revision.
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