[libvirt] RFC: CPU counting in qemu driver

[Daniel P. Berrange]

On Tue, Nov 23, 2010 at 03:34:20PM +0100, Jiri Denemark wrote:
> > > > What does Xen / 'xm info' report on such a host ?
> > 
> > nr_cpus                : 48
> > nr_nodes               : 1
> > sockets_per_node       : 4
> > cores_per_socket       : 12
> > threads_per_core       : 1
> > node_to_cpu            : node0:0-47
> 
> Hmm, this was for the default case when NUMA is turned off in hypervisor.
> After setting numa=on on xen command line, the result is a bit different:
> 
> nr_cpus                : 48
> nr_nodes               : 8
> sockets_per_node       : 0
> cores_per_socket       : 12
> threads_per_core       : 1
> node_to_cpu            : node0:0-5
>                          node1:6-11
>                          node2:12-17
>                          node3:18-23
>                          node4:24-29
>                          node5:30-35
>                          node6:36-41
>                          node7:42-47
> 
> 
> sockets_per_node is reported to be zero.

Ah well that's completely broken. Could be they did the
arithmetic nr_cpus / (nr_nodes * core_per_socket) and
got 0.5 which with integer truncation gives 0. Guess
Xen needs the same hack you're proposing for libvirt

Daniel