Two tools printed different opcodes for one function
phpdbg showed thirteen instructions and the optimizer showed nine. Both were right. How to read the notation, and which listing is the one that runs.
Tags
opcache
6 posts
Appending to a string is free until someone else holds it
The same .= statement took 0.269 ms and 218.836 ms in two loops that differ by one assignment. What a zend_string costs, where literals live, and why implode is not the fix.
What compiled DI containers actually buy you
Container compilation moves reflection from request time to build time. What that removes, what it costs, and when it matters.
OPcache, the JIT, and where time actually goes
OPcache removes compilation, not execution. The JIT reaches arithmetic-heavy code and little else. Where the remaining time lives.
Benchmarking PHP without lying to yourself
Microbenchmarks measure exactly what you tell them to, which is rarely what you meant. Method, noise, and the numbers worth reporting.
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.