Date: Wed, 15 Apr 2015 12:02:54 +0400 From: Dimitri Minaev <minaev@gmail.com> To: freebsd-questions@freebsd.org Subject: High LA caused by php-fpm Message-ID: <CANTUpDDwYoF4q3Tn%2BU4F132A83cO1gKUuGqoc8kD%2BAoQRdG4CA@mail.gmail.com>
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Hello,
Today, I tried to move our bunch of Drupal-powered web sites to a new
server. The old server was running FreeBSD 7.2 and I wanted to install a
newer version. In the meanwhile, I transferred the sites to the new server
(FreeBSD 10.1 on ZFS mirror, 1CPU with 6 cores and hyperthreading).
Everything looked fine, but as soon as the requests rate reached the usual
50-150 req/sec, the server shut up. Load average went up to 60, all
requests timed out and the backlog on php-fpm socket was full (2048). All
diagnostic tools showed that I/O was negligible, there was no swapping and
the only problem was high CPU usage caused by php-fpm.
Php-fpm was configured to start 100 children. When I lowered the number to
50, LA decreased to 30, but the requests were timing out as before.
Things looked like high LA was caused by bad PHP code, but it was the same
code that ran without problems on the old server. I tried to trace PHP
scripts using `truss', but could not find any problems -- just normal
operations.
Slow PHP requests logged by php-fpm contained no regular patterns that
might indicate problematic areas -- any kind of request ended up in the
slow log.
freebsd-questions@freebsd.org
I moved the sites back to the old server. The LA on the old one stayed high
until the queued requests had been processed. What's wrong with php-fpm?
Some specs:
FreeBSD 10.1-RELEASE-p9 running on Xeon(R) CPU E5-2420. Root partition is
on ZFS.
PHP 5.3.29 (5.3 required by developers). Nginx 1.6.2. MySQL runs on another
server and doesn't look like a bottleneck.
This is the upper part of `top' output:
Mem: 317M Active, 5866M Inact, 6819M Wired, 2724M Free
ARC: 5652M Total, 2382M MFU, 2554M MRU, 16K Anon, 32M Header, 684M Other
Swap: 4096M Total, 4096M Free
PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU COMMAND
34803 www 81 0 310M 172M RUN 4 7:40 31.05%
php-fpm{php-fpm}
34796 www 80 0 314M 175M CPU3 3 7:42 30.57%
php-fpm{php-fpm}
34797 www 81 0 310M 171M RUN 7 7:35 30.57%
php-fpm{php-fpm}
34785 www 80 0 306M 164M *Name 7 7:38 27.88%
php-fpm{php-fpm}
34790 www 80 0 310M 172M RUN 5 6:37 27.88%
php-fpm{php-fpm}
34783 www 80 0 310M 171M *Name 8 7:40 27.78%
php-fpm{php-fpm}
34805 www 80 0 310M 170M CPU6 6 7:38 27.59%
php-fpm{php-fpm}
34821 www 80 0 310M 171M RUN 11 7:39 26.95%
php-fpm{php-fpm}
34815 www 80 0 318M 178M CPU8 8 7:36 26.37%
php-fpm{php-fpm}
34822 www 80 0 310M 171M *Name 0 7:38 26.27%
php-fpm{php-fpm}
34813 www 80 0 314M 175M RUN 10 7:40 25.98%
php-fpm{php-fpm}
34816 www 79 0 314M 175M RUN 6 7:37 25.98%
php-fpm{php-fpm}
34826 www 79 0 314M 175M CPU1 1 7:34 25.98%
php-fpm{php-fpm}
34812 www 79 0 306M 167M RUN 6 7:33 25.88%
php-fpm{php-fpm}
34823 www 79 0 306M 168M *Name 2 7:35 25.78%
php-fpm{php-fpm}
34818 www 79 0 314M 174M *Name 0 7:42 25.68%
php-fpm{php-fpm}
34829 www 79 0 310M 172M CPU11 11 7:37 25.68%
php-fpm{php-fpm}
34806 www 79 0 310M 172M RUN 2 7:35 25.39%
php-fpm{php-fpm}
34817 www 80 0 318M 177M CPU7 7 7:38 25.29%
php-fpm{php-fpm}
Thanks.
--
With best regards,
Dimitri Minaev
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