Edit report at https://bugs.php.net/bug.php?id=73265&edit=1
ID: 73265
Updated by: nikic@php.net
Reported by: spam2 at rhsoft dot net
Summary: Loading browscap.ini at startup causes high memory
usage
Status: Open
Type: Bug
Package: Performance problem
Operating System: Linux
PHP Version: 7.0.14
Block user comment: N
Private report: N
New Comment:
It is a runtime option, see pcre.jit.
The PCRE JIT optimizes the case where a pattern is compiled once and used multiple times. Browscap
instead uses a huge amount of patterns only once. In this case the overhead of JIT compilation is
larger than the benefit during the matching of the pattern.
Previous Comments:
------------------------------------------------------------------------
[2016-12-16 17:29:31] spam2 at rhsoft dot net
indeed PHP 7.1 build with "--without-pcre-jit" is faster, while fast is relative given
that the test did only 10 calls - what is the purpose of the JIT then and can this not be a runtime
option for the cases where it brings a benefit?
<?php
$loops = 10;
for($count=1; $count<=$loops; $count++)
{
$x = get_browser('Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:50.0) Gecko/20100101
Firefox/50.0');
}
?>
[harry@srv-rhsoft:/scripts/php5-versus-7]$ ./test.sh
PHP 5.6
real 0m5.922s
user 0m5.861s
sys 0m0.027s
PHP 7.0
real 0m14.894s
user 0m14.716s
sys 0m0.079s
PHP 7.1
real 0m3.335s
user 0m3.285s
sys 0m0.031s
------------------------------------------------------------------------
[2016-12-16 16:57:15] spam2 at rhsoft dot net
wait - the JIT makes things slower?
i had assumed the opposite
so you tell me the change below should be the exactly opposite and with 7.1 configure can disable it
while --without-pcre-jit don't exist for 7.0 and it's always enabled there?
* Thu Dec 8 2016 Reindl Harald <h.reindl@thelounge.net>
- update to PHP 7.0.14
- add 'with-pcre-jit' for upcoming 7.1 to configure
------------------------------------------------------------------------
[2016-12-16 16:45:39] nikic@php.net
get_browser() is probably slower in PHP 7 because of the PCRE JIT. Most of the time in get_browser()
is spent is compiling regular expressions, and the JIT requires more complication time.
I have spent some time yesterday implementing many memory usage and performance optimizations for
browscap, I'll probably put up a PR today. However, the changes are very extensive, so not sure
if we target PHP 7.0 for that.
------------------------------------------------------------------------
[2016-12-16 16:38:58] spam2 at rhsoft dot net
so - now it is proven that get_browser() with PHP7 is magnitudes slower than with PHP5, i have
stored the binaries and extensions of the two versions running before and after the upgrade and gave
them identical configurations
PHP 5.6.26 (cli) (built: Oct 3 2016 12:45:59)
PHP 7.0.11 (cli) (built: Oct 5 2016 22:28:49)
______________________________
10 x get_browser('Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:50.0) Gecko/20100101
Firefox/50.0');
[harry@srv-rhsoft:/data/scripts/php5-versus-7]$ ./test.sh
PHP5
real 0m5.876s
user 0m5.799s
sys 0m0.034s
PHP7
real 0m14.396s
user 0m14.216s
sys 0m0.085s
______________________________
100 x get_browser('Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:50.0) Gecko/20100101
Firefox/50.0');
[harry@srv-rhsoft:/data/scripts/php5-versus-7]$ ./test.sh
PHP5
real 0m57.583s
user 0m57.180s
sys 0m0.052s
PHP7
real 2m23.615s
user 2m22.030s
sys 0m0.691s
______________________________
that's factor 2.4 and so in fact the asnwer to my initial question below is
"get_browser()" which was used until yesterday on every inital request with no active
session which is always true for "ab"-benchmarks
so one thing is the dramatical memory usage with 7.0.14 but in general the function got extremely
slow with the same "browscap.ini"
_________________________
we have two different inhouse cms-systems, while one is 46% faster with PHP7 the other one sucks
terrible - are there things known by developers which are internally slower now while most other
become faster and should be avoided?
------------------------------------------------------------------------
[2016-12-15 16:02:32] spam2 at rhsoft dot net
> From a quick test, performance of loading browscap.ini
> did not significantly change between 5.6 and 7.0.
> When you compared to PHP 5.6, were you also loading
> this browscap.ini?
*yes* - i synced the "php.spec" for 5.6 and 7.0 days before the upgrade so that it's
drop in and only the loadmodule line in httpd needs to be changed
what we did was
* restart webserver
* benchmark cms 1
* restart webserver
* benchmark cms 2
* note numbers
"dnf -y upgrade"
* restart webserver
* benchmark cms 1
* restart webserver
* benchmark cms 2
* note numbers
drop from 100 to 50 requests per second, well, that application is *using* get_browser() within a
if(function_exists('get_browser')) - hence i was able to add it to
'disabled_functions' - so it's not only about loading browscap and a likely
regression in 7.0.14 but also about get_browser() with the same "browscap.ini" became
noticeable slower
PHP 5.6.26:
Requests per second: 107.24 [#/sec] (mean)
Time per request: 279.741 [ms] (mean)
Time per request: 9.325 [ms] (mean, across all concurrent requests)
Transfer rate: 1531.03 [Kbytes/sec] received
PHP 7.0.11 PGO:
Requests per second: 56.30 [#/sec] (mean)
Time per request: 532.864 [ms] (mean)
Time per request: 17.762 [ms] (mean, across all concurrent requests)
Transfer rate: 803.75 [Kbytes/sec] received
PHP 7.0.14 NON-BROWSCAP:
Requests per second: 327.45 [#/sec] (mean)
Time per request: 61.077 [ms] (mean)
Time per request: 3.054 [ms] (mean, across all concurrent requests)
Transfer rate: 4754.80 [Kbytes/sec] received
------------------------------------------------------------------------
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