Critical PHP cache?

General questions
1

This document:

https://piwik.org/docs/optimize-how-to/#configure-piwik-for-speed

says:

“It is critical to use a PHP cache for high performance. Fortunately, PHP5 and newer versions such as PHP 7 come with this PHP cache included by default.”

How can I verify that I’m using a PHP cache? I’m using Piwik with nginx and php-fpm.

2

I’ve set opcache.enable=1 in fpm-php5.6/php.ini. Should that satisfy the critical need for a php cache for Piwik?

3

From what the OPCache web site says - yes. You could try using APC (This is what I use with four clustered servers) but OPCache is built in.