I have pushed a fix to main. But also note we provide precompiled Elixir versions per OTP version. Using a matching version will always give you the best results and that's not only about regexes. :)
On Thu, Mar 14, 2024 at 2:20 PM Jan Krüger <jan.krue...@gmail.com> wrote: > I've recently had to work on a code base that parses largish RDF XML > files. Part of the code base does relatively simple but regular expression > matches, but since the files are large, quite a lot of Regex.run calls. > While profiling I've noticed, that there are callouts to > :erlang.system_info, which fetches the PCRE version BEAM was compiled > against. > > An example regular expression from the code base in question matches the > schema part of a URL. I've replaced Regex.run with erlang's :re.run for > testing purposes, and at least for this case, there performance gain is > quite dramatic. > > Comparing fprof results: > > ``` > RDF.IRI.scheme/1 1176473 > 30615.618 2354.355 > --- > RDF.IRI.scheme/1 1176473 > 3531.955 2353.905 > ``` > > I found this thread in the google group, which actually talk about the > reasoning for fetching the version, and proposes and alternative. > > > https://groups.google.com/g/elixir-lang-core/c/CgFdxIONvGg/m/HN9ryeVXAwAJ?pli=1 > > Especially > > ``` > Taking a further look at the code, the issue with recompiling regexes on > the fly is that it makes executing the regexes more expensive, as we need > to compute the version on every execution. We could store the version in > ETS but that would have performance issues. Storing in a persistent_term > would be great, but at the moment we support Erlang/OTP 20+. Thoughts? > ``` > > Since this has a fairly noticeable impact, at least on all tests I've run, > I wanted to start a discussion, if this could be implemented/improved now. > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elixir-lang-core+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/44d498c7-82a4-46d2-89be-7919400e0297n%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/44d498c7-82a4-46d2-89be-7919400e0297n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to elixir-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4KBm8cN_1DUTXJqZge03_HW%2BQKC%2BMRYuLBzJejqoY9OsQ%40mail.gmail.com.
