Re: NUMA or not on dual Opteron

[Raphael Jacquot <raphael.jacquot@imag.fr>]

Sander wrote:
> Linus Torvalds wrote (ao):
> 
>>On Wed, 12 Jan 2005, Sergey S. Kostyliov wrote:
>>
>>>2.6.10-rc1 hangs at boot stage for my dual opteron machine
>>
>>Oops, yes. There's some recent NUMA breakage - either disable
>>CONFIG_NUMA, or apply the patches that Andi Kleen just posted on the
>>mailing list (the second option much preferred, just to verify that
>>yes, that does fix it).
> 
> 
> I was under the impression that NUMA is useful on > 2-way systems only.
> Is this true, and if not, under what circumstances is NUMA useful on
> 2-way Opteron systems?
> 
> In other words: why should one want NUMA to be enabled or disabled for
> dual Opteron?
> 
> Thanks in advance.
> 

Numa needs to be enabled on bi-opteron systems because each processor 
controls part of the memory. unlike the intel memory architecture, where 
processors share the same bus to access memory.
Numa in opteron systems is thus required to allow sharing of memory .