From: Markus Mottl <markus.mottl@gmail.com>
To: Brighten Godfrey <pbg@cs.berkeley.edu>
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Strange performance bug
Date: Tue, 28 Apr 2009 23:37:09 -0400 [thread overview]
Message-ID: <f8560b80904282037t61b27ce7lbe532b0f2dd54ee9@mail.gmail.com> (raw)
In-Reply-To: <324B24CA-9671-42C0-B722-C7710C0C45C7@cs.berkeley.edu>
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
next prev parent reply other threads:[~2009-04-29 3:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-29 2:43 Brighten Godfrey
2009-04-29 3:37 ` Markus Mottl [this message]
2009-04-29 4:31 ` [Caml-list] " Brighten Godfrey
2009-04-29 6:18 ` Alain Frisch
2009-04-29 6:27 ` Brighten Godfrey
2009-04-29 6:37 ` Alain Frisch
2009-04-29 8:29 ` Brighten Godfrey
2009-04-29 13:58 ` Markus Mottl
2009-04-29 14:48 ` Damien Doligez
2009-04-29 16:03 ` Markus Mottl
2009-04-29 19:19 ` Brighten Godfrey
2009-04-29 19:38 ` Markus Mottl
2009-04-29 20:23 ` Brighten Godfrey
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