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Anyone has experience measuring glibc regexp functions?
Are there any generic tests I need to run to make such a measurements (in addition to testing the exact patterns I intend to search)?
Thanks.
Regular expression performance depends much on which regular expression you’re using and which data you’re applying it to. There’s little point in just benchmarking a bunch of regular expressions. You have to compare actual code using a regex and your actual plain C alternative on your actual data.
As a rule of thumb, I’d say that if you already have properly functioning procedural code to do the text matching you need, just leave that in place. If you don’t have that code yet, I recommend to start with regexes as you’ll save yourself much development time (assuming you’re familiar with regexes). You can probably write procedural code that is faster than the equivalent regex, but the difference isn’t going to be dramatic. The effort of writing and maintaining the procedural code will be significantly higher than using a regex.