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Date: Sat, 30 Jul 2005 02:15:03 -0500
From: "Matthew D. Fuller" <fullermd@over-yonder.net>
To: Vivek Khera <vivek@khera.org>
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Subject: Re: i386 vs amd64 - benchmark results
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On Wed, Jul 27, 2005 at 11:52:30AM -0400 I heard the voice of
Vivek Khera, and lo! it spake thus:
> 
> The amd64 memory architecture is NUMA -- that is, depending on  how
> your RAM is layed out, some of it is faster to access for each
> processor.  Accessing RAM "local" to the other processor(s) is
> slower.

On the other hand, I've heard from various sources (this is all pure
hearsay, so trust it as much as it deserves) that in practice
NUMAization in this case isn't really a gain.  It's non-uniform, but
it's not nearly as non-uniform as a lot of applications of the term,
and the performance penalty is so small in absolute terms that the
added complexity that comes with NUMA awareness can actually be enough
to make it a net loss.


But then, I usually don't know what I'm talking about    8-}


-- 
Matthew Fuller     (MF4839)   |  fullermd@over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.