Yes, yes, that I understand.

I know that for example if I want to use host_passthrough then I must use cpu_sockets == numa_nodes.
My question is more conceptual, for me to understand.

For example: If I have a physical host with 1 physical processor (1 socket), can I define my instance with 2, 4, 8+ sockets? I mean, is it good practice? Is it correct to define the instance with 1 socket and increase the amount of socket colors?

Not sure if I could explain my question... In short, what is the relationship between the socket, cores and virtual thread and the socket, cores and physical thread.

PS: I'm not into the issue of passthrough or not.

Em seg., 4 de set. de 2023 às 13:10, <smooney@redhat.com> escreveu:

in general the only parameter you want to align to the physical host is the number of thread

so if the phsyical host has 2 thread per physical core then its best to also do that in the vm

we generally recommend setting the number of virutal socket equal to the number of virutal numa nodes
if the vm has no explict numa toploly then you should set sockets=1
else hw:cpu_sockets==hw:numa_nodes is our recomendation.

for windows in partcalar the default config generated is suboptimal as windows client only supprot 1-2 sockets
and windows serverver maxes out at 4 i believe.

On Mon, 2023-09-04 at 11:51 -0300, Jorge Visentini wrote:
> Hello Team,
>
> What is the difference between creating an instance with *4* or *8 virtual
> sockets*, since the hypervisor has only *4 physical sockets*.
> My question is where do sockets, cores and virtual threads fit into the
> physical hardware. I think this question is not just related to Openstack,
> but with any virtualization.
>
> My hypervisor configuration is as follows:
>
> CPU(s): 192
> Online CPU(s) list: 0-191
> Thread(s) per core: 2
> Core(s) per socket: 24
> Socket(s): 4
> NUMA node(s): 4
>
> Do you have any documentation that I can read and understand better?
>
> That we have a nice week!