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Date: Wed, 16 Jun 2004 02:11:07 +0200
From: Ralf Baechle <ralf@linux-mips.org>
To: Philippe St-Jacques <eukaryote@hotmail.com>
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cc: freebsd-mips@FreeBSD.org
Subject: Re: SGI - Origin 2000
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On Tue, Jun 15, 2004 at 09:39:52PM +0000, Philippe St-Jacques wrote:

> Hi. I will have soon 2 SGI Origin 2000 racks in here and I'd really like to 
> be informed about how well your work is progressing on those machines. Each 
> rack has 16 R10000 processors clocked at 250 mhz each, with 4 gig ram.

In addition to the issues raised by Juli there also is the lack [1] of
ccNUMA support in FreeBSD.  The SN0 architecture has a very low local to
remote memory latency ratio which tends to paper over the lack of such
OS support pretty well.  Also OS ccNUMA support comes at a cost at not
too much possible gain for a 4 processor system.  So scaling to 4
processors is not so much of an issue - it'll work more or less.  Starting
from 8 processors things are getting a bit ugly for most workloads we did
test and even more so at 16.  Don't get me started about scalability to a
midsize system of like 128 processors without well tuned NUMA support ;-)

  Ralf

[1] Forgive if that has changed - I'm not following FreeBSD development
    very much ...