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Re: [libvirt] Problem of host CPU topology parsing



On Fri, May 11, 2012 at 09:35:48 +0100, Daniel P. Berrange wrote:
> On Fri, May 11, 2012 at 04:21:48PM +0800, Osier Yang wrote:
> > Hi,
> > 
> > We have problem of host CPU topology parsing on special
> > platforms (general platforms are fine). E.g.
> > 
> > On a AMD machine with 48 CPUs [1] (4 sockets, 6 cores indeed
> > [2]), VIR_NODEINFO_MAXCPUS [3] will always return 24 as the
> > total CPU number.
> 
> If it is returning 24, then surely we have the 'nodes' value
> wrong in the virNodeInfo ? It sounds like it should have been
> set to 2  (4 * 6 * 2 => 48)

According to capabilities XML, there are 8 NUMA nodes so setting them to 2
wouldn't make much sense. It would be cool to know the correct hardware
topology but I'm not sure how to get that so that we can detect which part of
our detection mechanism is wrong. /proc/cpuinfo lists 48 CPUs but with only 4
distinct physical IDs and 6 distinct core IDs, which looks suspicious to me.

Jirka


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