Date: Wed, 03 Sep 2003 08:10:33 -0700
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Bernd Eckenfels <ecki@calista.eckenfels.6bone.ka-ip.net>
cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Scaling noise
Message-ID: <25950000.1062601832@[10.10.2.4]>
In-Reply-To: <1062590946.19059.18.camel@dhcp23.swansea.linux.org.uk>
References: <E19uQsT-0007mk-00@calista.inka.de> <1062590946.19059.18.camel@dhcp23.swansea.linux.org.uk>
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> multi node yes, numa not much and where numa-like systems are being used
> they are being used for message passing not as a fake big pc. 
> 
> Numa is valuable because
> - It makes some things go faster without having to rewrite them
> - It lets you partition a large box into several effective small ones 
>   cutting maintenance
> - It lets you partition a large box into several effective small ones
>   so you can avoid buying two software licenses for expensive toys
> 
> if you actually care enough about performance to write the code to do
> the job then its value is rather questionable. There are exceptions as
> with anything else.

The real core use of NUMA is to run one really big app on one machine, 
where it's hard to split it across a cluster. You just can't build an 
SMP box big enough for some of these things.

M.

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