Re: [libvirt] Non-contiguous NUMA cell numbers
n Mon, 2016-01-04 at 07:57 +0100, Michal Privoznik wrote:
On 23.12.2015 17:14, Andrea Bolognani wrote:
> Hi all,
>
> libvirt currently doesn't allow you to configure a guest with something
> like
>
> <cpu>
> <topology sockets='2' cores='5' threads='8'/>
> <numa>
> <cell id='0' cpus='0-39' memory='1048576'
unit='KiB'/>
> <cell id='16' cpus='40-79' memory='1048576'
unit='KiB'/>
> </numa>
This says you are configuring GUEST NUMA nodes, and last time I checked
qemu did not support non-continuous NUMA nodes. So, whatever your HOST
topology is, in GUEST you want NUMA nodes to be continuous.
I checked again and, as you and Daniel suggested, QEMU does not support
non-contiguous NUMA nodes, eg.
qemu-kvm \
-m 2048 \
-smp 80,sockets=2,cores=5,threads=8 \
-numa node,nodeid=0,cpus=0-39,mem=1024 \
-numa node,nodeid=16,cpus=40-79,mem=1024
outputs
qemu-kvm: numa: Node ID missing: 15
so indeed there's a very good reason for libvirt to reject that NUMA
configuration.
Cheers.
--
Andrea Bolognani
Software Engineer - Virtualization Team