[pve-devel] qemu-server : cpu hotplug rework

Alexandre DERUMIER aderumier at odiso.com
Thu Jan 22 14:13:31 CET 2015


>>Maybe a stupid question, but it seems that we can neither change 
>>'sockets' or 'cores' at runtime? 
no, sockets and cores are topology, and can't be change at runtime

sockets*cores = total vcpus you can plug.

with my patch, you need to start

vcpus: 1
socket: 2
cores: 2

this will start the guest with -smp 1,sockets=2,cores=2,maxcpus=4

you start with 1vcpu,and you can hotplug up to 4vcpus.


maybe do you don't have define vcpus ?







If so, this basically disable CPU hot-add, because you can never add an 
additional CPU? 
----- Mail original -----
De: "dietmar" <dietmar at proxmox.com>
À: "aderumier" <aderumier at odiso.com>, "pve-devel" <pve-devel at pve.proxmox.com>
Envoyé: Jeudi 22 Janvier 2015 11:45:41
Objet: Re: [pve-devel] qemu-server : cpu hotplug rework

Maybe a stupid question, but it seems that we can neither change 
'sockets' or 'cores' at runtime? 

If so, this basically disable CPU hot-add, because you can never add an 
additional CPU? 

If I try to remove a CPU I get: 

> vcpus: hotplug problem - online cpu unplug is not yet possible 

And if I want to add one: 

> vcpus: hotplug problem - you can't add more vcpus than maxcpus 

So what do I miss? 


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