I've run wordpress sites for more than a decade. I've never had an experience with opcode caching that wasn't unhappy.
I've used all of them. They all crash like a demolition derby in a brewery.
At one point I put Wordpress into a profiler and found that a only a few percent of total time was spent compiling PHP; most of the time spent was in waiting for MySQL and concatenating strings. So I just gave up on opcode caching.
The biggest improvements I got were:
* Whole page caching. In my case, WP-supercache spitting out gzip'd pages, with Nginx configured to find and serve those gzip'd pages.
* MySQL query caching.
* Moving MySQL into another server. This was a decent win when I was on spinning rust.
* SSDs. MySQL is a major chokepoint for Wordpress, because until recently its idea of a query plan was "let's join half the workloads on disk in gigantic join tables".
* Killing bad plugins. Even the "recent comments" plugin that ships with mainline is horrendous.
I've used all of them. They all crash like a demolition derby in a brewery.
At one point I put Wordpress into a profiler and found that a only a few percent of total time was spent compiling PHP; most of the time spent was in waiting for MySQL and concatenating strings. So I just gave up on opcode caching.
The biggest improvements I got were:
* Whole page caching. In my case, WP-supercache spitting out gzip'd pages, with Nginx configured to find and serve those gzip'd pages.
* MySQL query caching.
* Moving MySQL into another server. This was a decent win when I was on spinning rust.
* SSDs. MySQL is a major chokepoint for Wordpress, because until recently its idea of a query plan was "let's join half the workloads on disk in gigantic join tables".
* Killing bad plugins. Even the "recent comments" plugin that ships with mainline is horrendous.