PHP 5.5. has zend opcache support in core. Since APC is not updated from long time, we made a switch to new Zend Opcache. Below is our config and web-based stats viewer.
PHP’s Zend Opcache Config
In your
php.ini or /etc/php5/fpm/conf.d/05-opcache.ini zend_extension=opcache.so
opcache.memory_consumption=512
opcache.max_accelerated_files=50000
;following can be commented for production server
opcache.revalidate_freq=0
opcache.consistency_checks=1