Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?

Re^2: Performance of possessive quantifiers

by demerphq (Chancellor)
on Jan 28, 2008 at 14:09 UTC ( #664686=note: print w/replies, xml ) Need Help??

in reply to Re: Performance of possessive quantifiers
in thread Performance of possessive quantifiers



on 5.11

And it looks like something broke the superlinear cache. Even with atomic matching this pattern/string combination goes quadratic, as nothing anchors the start of the pattern. Without the atomic matching its worse. Im not sure what the deal is with $re++ either. I would have expected that to have similar performance to (?>$re)+, its possible thats actually a bug. Ill have to think about it.

Oh, and dont use benchmarks from a debugging perl. Depending on the code path you go through variable amounts of debugging goo, so using a debugging perl, especially a 5.9.x or later version will not give useful results even comparing features.


Replies are listed 'Best First'.
Re^3: Performance of possessive quantifiers
by tsee (Curate) on Jan 28, 2008 at 16:14 UTC

    Ah, thanks for that last remark, I'll keep it in mind for future testing.

    However, I double-checked and while I thought I remembered that -Dusedevel implied -DDEBUGGING, it doesn't seem so*. Hence, the 5.11 I used for the above results was no debugging build. Sorry for the confusion!


    * I did "./Configure -Dusedevel -de 2>&1 | grep -i debug" and "make -j3 | grep -i debug" without any mention of DEBUGGING.

      The -Dusedevel option to Configure just quiets the "WHOA THERE, is this a development version of perl" message that otherwise quits Configure.

      I verified my original benchmarks with non-debugging perls (I wasn't sure if my 5.10 had been debugging, and I missed to look at perl5.10.0 -V ;), it didn't change anything.

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://664686]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others meditating upon the Monastery: (5)
As of 2017-02-21 16:05 GMT
Find Nodes?
    Voting Booth?
    Before electricity was invented, what was the Electric Eel called?

    Results (313 votes). Check out past polls.