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Subject: Re: [RFC][PATCH] i386: Per node IDT
From: Arjan van de Ven <arjan@infradead.org>
To: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org
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Date: Mon, 11 Jul 2005 16:05:53 +0200
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On Mon, 2005-07-11 at 08:09 -0600, Zwane Mwaikambo wrote:
> On Mon, 11 Jul 2005, Arjan van de Ven wrote:
> 
> > On Mon, 2005-07-11 at 03:59 +0200, Andi Kleen wrote:
> > > Why per node? Why not go the whole way and make it per CPU?
> > 
> > Agreed, for two reasons even
> > 1) Per cpu allows for even more devices and cache locality
> > 2) While few people have a NUMA system, many have an SMP system so you
> > get a lot more testing.
> 
> Agreed, the first version was a per cpu one simply so that i could test it 
> on a normal SMP system. Andi seems to be of the same opinion, what do you 
> think of the hotplug cpu case (explained in previous email)?

you need to cope with hotplug of entire nodes anyway, or hotunplug of
the last cpu of a node. In fact I bet that the administration needed
will be LESS in the per cpu case (since you know it's the only one)
compared to the per node case.