Three numbers for one process, and memory_limit reads the middle one
memory_get_usage(), memory_get_usage(true) and ps disagree about one process. What each counts, which one memory_limit reads, and why a one-megabyte string costs two.
Subject 02 · 3 posts
Performance
Measurement: profiling, benchmark method, and optimization that arrives with a number attached.
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.