We found what's causing this - opcache was being loaded twice (both in cli and in php5-fpm):
# php -m (...) [Zend Modules] Zend OPcache Zend OPcache # ls -l |grep opcache lrwxrwxrwx 1 root root 32 Dec 3 07:15 05-opcache.ini -> ../../mods-available/opcache.ini lrwxrwxrwx 1 root root 32 Apr 22 12:55 20-opcache.ini -> ../../mods-available/opcache.ini The update created an extra opcache.ini symlink, opcache was being loaded twice, and it caused extremely poor performance. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1573625 Title: very high system load after upgrading to 5.5.9+dfsg-1ubuntu4.16 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/php5/+bug/1573625/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
