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Re: [libvirt] Problem of host CPU topology parsing



On Fri, May 11, 2012 at 10:46:26AM +0200, Jiri Denemark wrote:
> 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.

We probably want to grab the sysfs / proc files for this machine (and a
few other different machines) and use them to extend the nodeinfotest
test case data, since this is clearly a troublesome bit of code.

Daniel
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