Perl regex speed

malaigo has asked for the wisdom of the Perl Monks concerning the following question:

I have Perl on a Apple M1 Max Mac laptop (2021) and a Core i9 Mac laptop (2018). I assumed Perl compiled for arm64 would run much faster than Perl for x86_64.

With regex, it doesn't seem to be the case. The one-liner I used was time perl -e '$n = shift; $na = "a" x $n; print $na =~ /(a?){$n}a{$n}/' X where X ranges over 5,10,15,20,24,30 etc.

Results graphed at sandiway.arizona.edu/temp/538/perl%20comparison.png

EDIT: direct link

Comment on Perl regex speed Select or Download Code

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Re: Perl regex speed by jwkrahn (Abbot) on Oct 25, 2022 at 08:08 UTC
You have a seriously bad regular expression. I don't see how it could be improved by running on a different architecture. Try running it like this: `perl -Mre=debug -le'$n = shift; $na = "a" x $n; print $na =~ /(a?){$n} +a{$n}/'` [download]	[reply] [d/l]
Re^2: Perl regex speed by malaigo (Novice) on Oct 25, 2022 at 21:47 UTC
You don't understand. This is for teaching. It's supposed to be a worst case scenario for backtracking regex implementations. The question is how come the arm64 version doesn't blow away the x86 one.	[reply]
Re: Perl regex speed by cavac (Prior) on Oct 25, 2022 at 08:01 UTC
The link to the graph you posted is invalid. I assume the correct one is https://sandiway.arizona.edu/temp/538/perl%20comparison.png Tip: Don't use spaces in filenames. This always leads to trouble. PerlMonks XP is useless? Not anymore: XPD - Do more with your PerlMonks XP	[reply]
Re^2: Perl regex speed by malaigo (Novice) on Oct 25, 2022 at 21:49 UTC
Yes, %20. And generally, you are correct. I don't mind linking, but it wouldn't let me link in the original query for some reason.	[reply]
Re^3: Perl regex speed by cavac (Prior) on Oct 27, 2022 at 10:19 UTC
Did you just copy&paste the link from somewhere? PM doesn't do any encoding for you, it just uses your text to generate HTML. Depending on the source of your link, you might have to do the encoding step manually (or run it through a browser url input once). And you have to add the link HTML tags yourself, PM doesn't do that for you. `Text only: https://example.com/Hello World https://example.com/Hello%20World Wrong encoding: <a href="https://example.com/Hello World">Examle link</a> Correct encoding: <a href="https://example.com/Hello%20World">Example link</a>` [download] PerlMonks XP is useless? Not anymore: XPD - Do more with your PerlMonks XP	[reply] [d/l]
Re: Perl regex speed by dave_the_m (Monsignor) on Oct 25, 2022 at 17:51 UTC
so, what's your question?	[reply]
Re^2: Perl regex speed by malaigo (Novice) on Oct 25, 2022 at 21:51 UTC
The question is, why isn't the latest Apple Silicon implementation faster than the Intel one on Perl regex?(Assuming it is arm64 and not emulated x86_64.)	[reply]
Re^3: Perl regex speed by dave_the_m (Monsignor) on Oct 26, 2022 at 08:29 UTC
Why would you expect arm64 to be noticeably faster? Have ARM patented some amazing new technology that Intel can't use? Dave.	[reply]
Re^4: Perl regex speed by malaigo (Novice) on Oct 27, 2022 at 03:07 UTC
Re^5: Perl regex speed by Anonymous Monk on Oct 27, 2022 at 06:42 UTC
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