PHP 8.0.12: $ time php fib.php 42 42 433494437 real 0m29.274s user 0m29.003s sys 0m0.105s $ time php -dopcache.enable_cli=1 fib.php 42 42 433494437 real 0m26.341s user 0m26.179s sys 0m0.058s ---------------------------------------- PHP 7.3.5: $ time php fib.php 42 42 433494437 real 10m23.573s user 10m16.592s sys 0m1.828s ---------------------------------------- Settings for PHP 8: PHP Version => 8.0.12 auto_globals_jit => On => On pcre.jit => 1 => 1 opcache.jit => tracing => tracing opcache.jit_bisect_limit => 0 => 0 opcache.jit_blacklist_root_trace => 16 => 16 opcache.jit_blacklist_side_trace => 8 => 8 opcache.jit_buffer_size => 0 => 0 opcache.jit_debug => 0 => 0 opcache.jit_hot_func => 127 => 127 opcache.jit_hot_loop => 64 => 64 opcache.jit_hot_return => 8 => 8 opcache.jit_hot_side_exit => 8 => 8 opcache.jit_max_exit_counters => 8192 => 8192 opcache.jit_max_loop_unrolls => 8 => 8 opcache.jit_max_polymorphic_calls => 2 => 2 opcache.jit_max_recursive_calls => 2 => 2 opcache.jit_max_recursive_returns => 2 => 2 opcache.jit_max_root_traces => 1024 => 1024 opcache.jit_max_side_traces => 128 => 128 opcache.jit_prof_threshold => 0.005 => 0.005
