4 ms·

If you discard regexredux, then Rust is faster than C and C++ at average: see average bar at "How many times slower graph" [1]. regexredux program is outlier i

If you discard regexredux, then Rust is faster than C and C++ at average: see average bar at "How many times slower graph" [1]. regexredux program is outlier in Rust, because replacement of a regex in string is slower in regex crate, because author of regex crate chose to implement safer, but slower algorithm. To fix this, regex crate must be updated or replaced. I spent two weekends on this. [1]: https://benchmarksgame-team.pages.debian.net/benchmarksgame/which-programs-are-fast.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/...

igouy 7y ago
mandelbrot is outlier in Rust, because… :-)
- v_lisivka 7y ago
  Because hardware acceleration is used in C and C++ versions. I will fix this soon.
igouy 7y ago
> To fix this, regex crate must be updated or replaced. I somehow doubt pcre2 is being changed to make the tiny toy C programs run better. > I spent two weekends on this. So shouldn't we assume the program performance simply reflects all-those-hours you've spent working on it?
- v_lisivka 7y ago
  Look at the program: fn find_replaced_sequence_length(sequence: String) -> usize { // Replace the following patterns, one at a time: let substs = vec![ ("tHa[Nt]", "<4>"), ("aND|caN|Ha[DS]|WaS", "<3>"), ("a[NSt]|BY", "<2>"), ("<[^>]*>", "|"), ("\\|[^|][^|]*\\|", "-"), ]; // Perform the replacements in the sequence: substs .iter() .fold(sequence, |s, (re, replacement)| { regex(re) .replace_all(&s, NoExpand(replacement)).into_owned() }).len() } It measures performance of RE engine. I can switch from regex crate to PCRE2, and program performance will match C.
  - igouy 7y ago
    > I can switch from regex crate to PCRE2, and program performance will match C. Perhaps it would; those measurements have not been made. What does that have to do with re-writing libraries to make tiny toy programs run better? What does that have to do with program performance being a proxy for programmer effort?

igouy 7y ago

mandelbrot is outlier in Rust, because… :-)

v_lisivka 7y ago
Because hardware acceleration is used in C and C++ versions. I will fix this soon.

igouy 7y ago

> To fix this, regex crate must be updated or replaced. I somehow doubt pcre2 is being changed to make the tiny toy C programs run better. > I spent two weekends on this. So shouldn't we assume the program performance simply reflects all-those-hours you've spent working on it?

v_lisivka 7y ago
Look at the program: fn find_replaced_sequence_length(sequence: String) -> usize { // Replace the following patterns, one at a time: let substs = vec![ ("tHa[Nt]", "<4>"), ("aND|caN|Ha[DS]|WaS", "<3>"), ("a[NSt]|BY", "<2>"), ("<[^>]*>", "|"), ("\\|[^|][^|]*\\|", "-"), ]; // Perform the replacements in the sequence: substs .iter() .fold(sequence, |s, (re, replacement)| { regex(re) .replace_all(&s, NoExpand(replacement)).into_owned() }).len() } It measures performance of RE engine. I can switch from regex crate to PCRE2, and program performance will match C.
- igouy 7y ago
  > I can switch from regex crate to PCRE2, and program performance will match C. Perhaps it would; those measurements have not been made. What does that have to do with re-writing libraries to make tiny toy programs run better? What does that have to do with program performance being a proxy for programmer effort?