Obviously, because the PHP regex engine is written in C, not in PHP. It's more like Rust's regex crate vs C PCRE rather than PHP, or who calls system call faste

Obviously, because the PHP regex engine is written in C, not in PHP. It's more like Rust's regex crate vs C PCRE rather than PHP, or who calls system call faster. While Rust's IO is locked[1] and doesn't buffer (which is slower than buffered, unsynchronized IO like other languages). And regex crate is slow when capturing, which is used on the "benchmark". Reference: https://www.reddit.com/r/rust/comments/5zit0e/regex_captures_slow_compared_to_python/ https://www.reddit.com/r/rust/comments/5zit0e/regex_captures... 2 years ago, but it's still valid to me, I've just tested it and it's much slower as I expected. Feel free to correct me if I'm wrong :) [1]: https://doc.rust-lang.org/std/io/fn.stdout.html https://doc.rust-lang.org/std/io/fn.stdout.html