Thanks a lot. I'm also happy to share our case, and my fprof results, if that helps. I am very sure that my erlang, and elixir versions match, on the machine where I've tested this. Replacing Regex.run with an identical call to :re.run should show the performance improvement I've mentioned. The regex we've tested this on is:
~r/^([a-z][a-z0-9\+\-\.]*):/i On Thursday, March 14, 2024 at 5:55:47 PM UTC+1 marcel...@googlemail.com wrote: > I'm the maintainer of RDF.ex library with the RDF.IRI module mentioned in > the OP. I can confirm that this fix doesn't affect the problem, since we're > actually not using `URI.parse/1` most of the time (we use it only when > dealing with relative URIs). Even in this case the `Regex.version/0` call > in `Regex.safe_run/3` ( > https://github.com/elixir-lang/elixir/blob/b8fca42e58850b56f65d0fb8a2086f2636141f61/lib/elixir/lib/regex.ex#L533) > > still performs the `:erlang.system_info/0` call. > > On Thursday 14 March 2024 at 17:15:40 UTC+1 jan.k...@gmail.com wrote: > >> I read the commit, and I don't it fixes what our actual problem was. See >> my comment above. The problem is the actual call to :re.version, not the >> recompilation of the regex >> >> On Thursday, March 14, 2024 at 4:37:43 PM UTC+1 José Valim wrote: >> >>> 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.k...@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-co...@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/507e6bd5-9be9-49a3-b039-45c2173fd509n%40googlegroups.com.
