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Strange performance bug
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Date: | 2009-04-29 (03:37) |
From: | Markus Mottl <markus.mottl@g...> |
Subject: | Re: [Caml-list] Strange performance bug |
On Tue, Apr 28, 2009 at 22:43, Brighten Godfrey <pbg@cs.berkeley.edu> wrote: > I've encountered a very odd performance problem which I suspect is not a bug > in my code. Could it be the compiler, or maybe PCRE? I'm not sure it solves your problem (haven't tried the example), but just looking at the code there is clearly a performance bug: the pattern is passed to Pcre.pmatch "on the fly" using label "~pat". This is ok and convenient if it is used only once, but is bad if it happens in a loop. Precompile the regular expression outside of the loop (let rex = Pcre.regexp "...") and pass it in with label "~rex" to solve this problem. Regards, Markus -- Markus Mottl http://www.ocaml.info markus.mottl@gmail.com