Open Stack

On 01/26/2015 05:37 PM, Jay Pipes wrote:
> On 01/26/2015 07:33 AM, Chris Friesen wrote:
>> Hi,
>>
>> I'm interested in the recent work around NUMA support for guest
>> instances
>> (https://blueprints.launchpad.net/nova/+spec/virt-driver-numa-placement), but
>> I'm having some difficulty figuring out what versions of libvirt and
>> qemu are required.
>>
>>  From the research that I've done it seems like qemu 2.1 might be
>> required, but I've been unable to find a specific version listed in the
>> nova requirements or in the openstack global requirements.  Is it there
>> and I just can't find it?
>>
>> If it's not specified, and yet openstack relies on it, perhaps it should
>> be added.  (Or at least documented somewhere.)
>
> Hi Chris,
>
> The constants starting here:
>
> http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/libvirt/driver.py#n340
>
> should answer your questions.

Thanks, that's useful.

Looking at the history of that file, I see git commit d927635 adding in support 
for NUMA memory allocation policy using the libvirt numatune option, but it 
doesn't modify the libvirt or qemu version requirements.

When I asked on the libvirt list they said that qemu 2.1 was needed to support 
pinning memory on host NUMA nodes.  Do we get around that somehow?

Also, the _get_host_numa_topology() code uses pages.size and pages.total which 
would seem to depend on hugepages support in libvirt, but that was only added in 
1.2.6.  I don't see any hugepage-related versions listed here for libvirt.  (I 
actually ran into a problem here before upgrading libvirt, it threw an exception 
in _get_host_numa_topology().  If I recall it was because cell.mempages was 
empty since libvirt was too old.)

Chris