From: "David Leimbach" <leimy2k@gmail.com>
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] Current status of amd64 port?
Date: Fri, 16 Nov 2007 07:33:38 -0800 [thread overview]
Message-ID: <3e1162e60711160733p152bbbd5qbf29e1d52de650f4@mail.gmail.com> (raw)
In-Reply-To: <d80822544d16890ae41c09db6a82e2de@coraid.com>
On Nov 16, 2007 6:46 AM, erik quanstrom <quanstro@coraid.com> wrote:
> > Per your second a), performance does often improve quite a bit with 2x
> > the general purpose registers.
> >
>
> do you have some specific numbers to back up this claim?
>
> - erik
>
Not handy, but I used to build MPI applications on Opterons in 32bit
mode, then build them in 64bit mode, and nearly always get a
performance boost out of the 64bit. Which was the exact opposite that
I'd get on PPC 32 vs 64 bit.
PPC's a different animal, using 32bit instructions even when in a
"64bit mode" (doesn't really have modes), some immediate memory loads
can use up to 5 instructions in assembly... I didn't look much deeper
than that.
I know I'm not alone in this observation either.
I'm sure I could google some results, but I can't currently produce
any of my own (unless I can get some time to do so on Leopard, since
it supports both).
Dave
next prev parent reply other threads:[~2007-11-16 15:33 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-15 22:51 Anthony Sorace
2007-11-15 22:56 ` Uriel
2007-11-16 6:14 ` ron minnich
2007-11-15 23:14 ` Tharaneedharan Vilwanathan
2007-11-15 23:39 ` erik quanstrom
2007-11-16 0:10 ` Tharaneedharan Vilwanathan
2007-11-16 0:18 ` Anthony Sorace
2007-11-16 7:57 ` Robert William Fuller
2007-11-16 10:05 ` erik quanstrom
2007-11-16 10:20 ` Charles Forsyth
2007-11-16 22:38 ` ron minnich
2007-11-16 22:46 ` Tharaneedharan Vilwanathan
2007-11-16 23:20 ` erik quanstrom
2007-11-16 23:19 ` erik quanstrom
2007-11-16 23:40 ` Charles Forsyth
2007-11-16 23:38 ` ron minnich
2007-11-16 23:56 ` Charles Forsyth
2007-11-16 23:54 ` erik quanstrom
2007-11-17 0:14 ` ron minnich
2007-11-17 0:23 ` Charles Forsyth
2007-11-17 0:30 ` ron minnich
2007-11-17 0:33 ` erik quanstrom
2007-11-17 1:08 ` Charles Forsyth
2007-11-17 6:38 ` Geoffrey Avila
2007-11-16 14:41 ` David Leimbach
2007-11-16 14:46 ` erik quanstrom
2007-11-16 15:33 ` Wilhelm B. Kloke
2007-11-16 15:33 ` David Leimbach [this message]
2007-11-16 15:35 ` David Leimbach
2007-11-16 15:53 ` Charles Forsyth
2007-11-16 16:21 ` David Leimbach
2007-11-16 0:11 Joshua Wood
2007-11-16 14:43 ` David Leimbach
[not found] <20071116170014.595B2108A1@mail.cse.psu.edu>
2007-11-16 23:10 ` Joshua Wood
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