libvirt users - Jul 2012 - numa query

Hi,

I have a host machine which contains 4 numa nodes each with 2 GB memory and 4
cpus. I am using qem-kvm hypervisor.

I am trying to create a guest with the similar topology (4 numa nodes, with only
2 vcpus and 1 GB memory) as host. Each vcpu is 1-1 pinned to physical cpus(i.e.
guest{socket0 cpu0} is pinned to host{socket0 cpu0). But one critical
requirement is that one guest socket should not have memory from two host
sockets to avoid numa access completely.

With the current constructs of numa/topology I am able to create the guest. But
memory is not mapped as socket 1-1. numatune is not helping. Please suggest a
possible way.

Thanks,
Kapil

On 2012?07?05? 21:50, kapil jain wrote:
> Hi,
>
> I have a host machine which contains 4 numa nodes each with 2 GB memory and
4 cpus. I am using qem-kvm hypervisor.
>
> I am trying to create a guest with the similar topology (4 numa nodes, with
only 2 vcpus and 1 GB memory) as host. Each vcpu is 1-1 pinned to physical
cpus(i.e. guest{socket0 cpu0} is pinned to host{socket0 cpu0). But one critical
requirement is that one guest socket should not have memory from two host
sockets to avoid numa access completely.
>
> With the current constructs of numa/topology I am able to create the guest.
But memory is not mapped as socket 1-1. numatune is not helping. Please suggest
a possible way.
>
Hi, kapil,

There is no way to control the mapping between guest numa nodes
and host numa nodes via libvirt now. There are actually discussion
about this in qemu/kvm upstream:

http://thread.gmane.org/gmane.comp.emulators.qemu/123001

http://article.gmane.org/gmane.comp.emulators.kvm.devel/57684

http://article.gmane.org/gmane.comp.emulators.kvm.devel/58835

http://lists.gnu.org/archive/html/qemu-devel/2012-07/msg00209.html

Regards,
Osier