From: Jon Harrop <jon@ffconsultancy.com>
To: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] OCaml image blending performance
Date: Thu, 7 Feb 2008 15:04:24 +0000 [thread overview]
Message-ID: <200802071504.24169.jon@ffconsultancy.com> (raw)
In-Reply-To: <20080207110154.GA24561@annexia.org>
On Thursday 07 February 2008 11:01:54 Richard Jones wrote:
> On Wed, Feb 06, 2008 at 11:34:02PM +0000, Jon Harrop wrote:
> > In this case, most of the speed loss can be regained by simply
> > aggressively inlining everything, which is exactly what you (ab)used
> > C macros for in the C code.
>
> I don't understand this. In 'blend2.ml' (which I was responsible for)
> C macros are used to inline all the OCaml functions the same as in the
> C version. Yet it's still 70% slower than the C version.
>
> My suspicion was that it was to do with his use of a string as a byte
> array.
I suspect OCaml's 31-bit integers are responsible for the remaining slowdown.
You might try using 32-bit integers (Int32) but I'm not sure ocamlopt will
unbox them as aggressively as it does floats (I've never tried it).
--
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
http://www.ffconsultancy.com/products/?e
next prev parent reply other threads:[~2008-02-07 15:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-06 20:29 Ilmari Heikkinen
2008-02-06 22:12 ` [Caml-list] " Pal-Kristian Engstad
2008-02-06 23:30 ` Jon Harrop
2008-02-06 23:34 ` Jon Harrop
2008-02-07 11:01 ` Richard Jones
2008-02-07 11:13 ` Dominique Martinet
2008-02-07 12:29 ` Mauricio Fernandez
2008-02-07 15:04 ` Jon Harrop [this message]
[not found] ` <854c25eb0802070607t4b2ed641xa3bc19e8384ce23@mail.gmail.com>
2008-02-07 14:10 ` Ilmari Heikkinen
2008-02-07 14:08 ` Jon Harrop
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