PHP Opcache Explained

Explore the inner workings of PHP's OPCache mechanism in this comprehensive PHP UK Conference talk. Delve into the details of how OPCache functions, its impact on PHP, and optimal setup strategies for maximum performance and stability. Gain a thorough understanding of PHP's engine, its virtual machine, and the intricate interactions between OPCache and PHP's complex architecture. Learn about opcode caching, shared memory usage, PHP opcodes, compilation processes, and various optimization techniques. Discover the OPCache API, essential settings, statistics, and keys. Understand the importance of cache consistency, restart scenarios, and logging. By the end of this talk, acquire a complete understanding of OPCache and its role in accelerating PHP applications.

Introduction
What is PHP
How does PHP work
Virtual Machine
Passing and Compile
Compile time
Classes
Cash Opcache
Load Opcache from Shared Memory
PHP
Opcodes
PHP Code
Appa
Examples
Complex Code
Post incrementation
Reusing temporary variables
Constant substitution
Compilation
Invariant Motion
String
Optimization
Opcache API
Opcache Settings
Opcache Statistics
Opcache Keys
Cached Keys
Cash
Why restart
Opcache log
Fast shut down
Consistency check
Questions
Stats