Re: [Qemu-devel] cpu hotplug and windows guest (win2012r2)

[Alexandre DERUMIER <aderumier@odiso.com>]

Hi,

I have tried with numa enabled, and it's still don't work.
Can you send me your vm qemu command line ?


Also, with numa I have notice something strange with "info numa" command.

starting with -smp socket=2,cores=1

# info numa
2 nodes
node 0 cpus: 0
node 0 size: 2048 MB
node 1 cpus: 1
node 1 size: 2048 MB

ok


now:

starting with -smp 1,socket=2,cores=1,maxcpus=2

# info numa
2 nodes
node 0 cpus: 0
node 0 size: 2048 MB
node 1 cpus:
node 1 size: 2048 MB

ok


now hotplug cpu

# cpu-add 1
# info numa
2 nodes
node 0 cpus: 0 1
node 0 size: 2048 MB
node 1 cpus:
node 1 size: 2048 MB


cpu1 has been hotplugged on numa node0 ??????


----- Mail original -----
De: "Andrey Korolyov" <andrey@xdel.ru>
À: "aderumier" <aderumier@odiso.com>
Cc: "qemu-devel" <qemu-devel@nongnu.org>
Envoyé: Mercredi 14 Janvier 2015 17:07:41
Objet: Re: [Qemu-devel] cpu hotplug and windows guest (win2012r2)

On Fri, Jan 9, 2015 at 4:35 PM, Andrey Korolyov <andrey@xdel.ru> wrote: 
> On Fri, Jan 9, 2015 at 1:26 PM, Alexandre DERUMIER <aderumier@odiso.com> wrote: 
>> Hi, 
>> 
>> I'm currently testing cpu hotplug with a windows 2012R2 standard guest, 
>> 
>> and I can't get it too work. (works fine with linux guest). 
>> 
>> host kernel : rhel7 3.10 kernel 
>> qemu 2.2 
>> 
>> 
>> qemu command line : -smp cpus=1,sockets=2,cores=1,maxcpus=2 
>> 
>> Started with 1cpu, topogoly is 2sockets with 1cores. 
>> 
>> 
>> Then 
>> 
>> qmp# cpu-add 1 
>> 
>> 
>> I can see a new cpu is windows device manager, and event log in the device said that it's online. 
>> 
>> So it should be ok, but. 
>> 
>> I can't see new processor in taskmanager or perfmon. (I had tried to relaunch them to be sure.). 
>> 
>> 
>> So, it is a windows bug ? Does I need to do something else ? 
>> 
> 
> Did you populated appropriate topology in arguments? As far as I can 
> remember from pre-1.1 era CPU hotplug not worked with windows, so it 
> should be neither lack of configured NUMA or a simply OS-specific 
> issue. 

Just to let anyone know that it works well: 

http://xdel.ru/downloads/windows-hotplugged-cpu.png 

Topology is a bit rotten (I have two sockets with single CPU in each) 
and I *need* to specify non-zero amount of memory for each numa node 
to be seen, if each CPU belongs to different node for example but 
everything else is just fine.