From: ebiederman@lnxi.com (Eric W. Biederman)
To: "Joakim Tjernlund" <Joakim.Tjernlund@lumentis.se>
Cc: "Wolfgang Denk" <wd@denx.de>, "Marc Singer" <elf@buici.com>,
<linux-mtd@lists.infradead.org>
Subject: Re: crc32() optimization
Date: 10 Nov 2002 16:56:30 -0700 [thread overview]
Message-ID: <m3k7jl0yj5.fsf@maxwell.default.domain> (raw)
In-Reply-To: <002b01c2890c$f2c058e0$0200a8c0@telia.com>
"Joakim Tjernlund" <Joakim.Tjernlund@lumentis.se> writes:
> > In message <001301c28909$743f1f40$0200a8c0@telia.com> you wrote:
> > > I could not wait until tomorrow, so I did it now instead.
> > > The result was worse. The best I got was 7% improvement.
> > > I tried 16, 8, 6 and 4 as unrolling steps.
> >
> > Makes no sense to me. Should be at least as efficient as your
> > original code (marginally better).
>
> I don't understand this either.
> Anyone?
You might try it with 6. But a lot depends on what gcc can do with
it and gcc may not be like all of those potential entry points..
Running gcc -S and checking to see the difference in the generated
assembly might be instructive.
Eric
next prev parent reply other threads:[~2002-11-10 23:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <F122OgRGkQ6mBySsxVY00000854@hotmail.com>
[not found] ` <24987.1036797874@passion.cambridge.redhat.com>
2002-11-10 15:28 ` crc32() optimization Joakim Tjernlund
2002-11-10 18:43 ` Marc Singer
2002-11-10 19:25 ` Wolfgang Denk
2002-11-10 20:05 ` Joakim Tjernlund
2002-11-10 21:00 ` Wolfgang Denk
2002-11-10 21:22 ` Joakim Tjernlund
2002-11-10 22:35 ` Joakim Tjernlund
2002-11-10 22:41 ` Wolfgang Denk
2002-11-10 23:00 ` Joakim Tjernlund
2002-11-10 23:56 ` Eric W. Biederman [this message]
2002-11-11 1:31 ` Marc Singer
2002-11-11 1:37 ` Wolfgang Denk
2002-11-11 4:42 ` Marc Singer
2002-11-25 15:55 ` Herman Oosthuysen
2002-11-25 16:12 ` Joakim Tjernlund
2002-11-11 0:50 ` Marc Singer
2002-11-10 20:04 ` Joakim Tjernlund
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