What happens when PHP runs your code
A request walks from the SAPI to the Zend VM — lexing, compilation to opcodes, the OPcache lookup that skips both, and execution.
A technical publication about PHP
Understanding PHP below the abstraction.
A technical publication about PHP internals, performance, architecture, and production behavior — measurements over assumptions, trade-offs over rules.
opcache.opt_debug_level=0x20000PHP 8.5
readPlain:0000 CV0($o) = RECV 10001 T1 = FETCH_OBJ_R CV0($o) string("v")0002 RETURN T1readBacked:0000 CV0($o) = RECV 10001 T1 = FETCH_OBJ_R CV0($o) string("v")0002 RETURN T1readVirtual:0000 CV0($o) = RECV 10001 T1 = FETCH_OBJ_R CV0($o) string("v")0002 RETURN T1Latest posts
All posts
Five subjects
Every post belongs to one of them. Each subject has its own archive, newest first.
Internals
The engine: compilation, the Zend VM, memory layout, and the data structures behind the values you pass around.
Performance
Measurement: profiling, benchmark method, and optimization that arrives with a number attached.
Architecture
How an application is put together: boundaries, dependency injection, layering, and what a framework design costs later.
Runtime
Production behavior: PHP-FPM pools, worker processes, long-running runtimes, and where memory goes over a day.
Ecosystem
The tooling and standards around the language: Composer, static analysis, and the PSRs.
Series
Written to be read in order.
Each series builds one argument across several posts. Start at part one; every part links to the next.
Read in orderValues and memory
What a PHP value is made of, what it costs to hold one, and when the engine decides to copy it.
Reading the engine
How to get opcodes out of PHP, what the dispatch loop does with them, and what the optimizer changed before either happened.
Where the time goes
What a profiler can and cannot see, how to read what it produces, and where a request's time actually accumulates.