rebar is a tool that measures the performance of different regex engines on various benchmarks. It provides information on how to build rebar, use its sub-commands, and contribute to its benchmark selection and evaluation. The results of the benchmarks are summarized, showing the relative speed of each regex engine. The summary includes search time and compile time rankings based on the geometric mean of speed ratios. The benchmarks are grouped based on related workloads, such as literal patterns and literal alternates. The author highlights the challenges and optimizations involved in these benchmarks, particularly in dealing with multiple substring search.
https://github.com/BurntSushi/rebar