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From: Chet Murthy <chet@watson.ibm.com>
To: "Jörgen Gustavsson" <gustavss@cs.chalmers.se>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Memory management dominates running time
Date: Sun, 05 Jan 2003 06:35:17 -0500	[thread overview]
Message-ID: <200301051135.h05BZHiY009447@nautilus-chet.watson.ibm.com> (raw)
In-Reply-To: Your message of "Fri, 03 Jan 2003 22:58:34 +0100." <Pine.SOL.4.30.0301032109550.17168-100000@muppet20.cs.chalmers.se>


By using gprof, and doing a little careful counting, you can 
often find out where egregious allocations are happening, and
eliminate them.

I can't give you good pointers on this, because, well, it's a bit of
an art, and takes a lot of experience.  But it _is_ doable, and I have
done it to nontrivial programs in Caml, as well as in Java, attaining
speedups of 2x, 3x, without much code-restructuring.

E.g., once, I took a Stream-based parser, and wrote a Stream module
which only supported "char Stream", and only for parsing.

By writing a few auxiliary functions in addition to this, I was able
to reduce the consing associated with stream-based parsing (the
constant creation of "Some _" blocks) significantly, and got a rather
large speedup.

I was able to see that this was important, basically by looking around
in the gprof profile and trying to follow where the allocation were
happening.

--chet--
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  parent reply	other threads:[~2003-01-08  1:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-01-03 21:58 Jörgen Gustavsson
2003-01-04  1:20 ` Norman Ramsey
2003-01-05 11:35 ` Chet Murthy [this message]
2003-01-08 12:58   ` Jörgen Gustavsson
2003-01-08 14:20 ` Damien Doligez
2003-01-08 22:23   ` [Caml-list] GlSurf 1.2 available Christophe Raffalli

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