OPCache is PHP's default OPCode cache mechanism, which has been introduced with PHP5.5. You can use it for 5.3, 5.4 or 5.5. This talk will detail how OPCache works, what it does to PHP and how to set it up so that you can deal with maximum performance and stability. We'll recall how PHP works, how its engine works, and how OPCache interacts with this complex machine to effectively accelerate it. You'll know everything about OPCache at the end of this talk.