that was PHP 7.4.25 Yes this is a microbenchmark. Yes, I know binet's formula... Yes it's weird function calls are so slow in php. with php 8.0 (jit enabled)

that was PHP 7.4.25 Yes this is a microbenchmark. Yes, I know binet's formula... Yes it's weird function calls are so slow in php. with php 8.0 (jit enabled) you get something like 120s (for n= 42)