[pve-devel] RFC : qemu-server : add cpu_hotplug

[Alexandre DERUMIER]

>>You mean wheezy 3.2 Kernel? It does not have a 3.10 Kernel. 

Wheezy-backports. (it's to compare with jessie).
kernel are same, so maybe udev from wheezy is too old to auto enable cpu.

(But hotplug of the cpu itself works fine with kernel 3.2, maybe 2.6.32, I don't have tested it yet)



>>Does this mean, that memory hotplug works too? 

It mean that memory hotplug will auto work in guest, when support will be added to qemu ;)
I think it's already working with vmware (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012764)


----- Mail original ----- 

De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag> 
À: "Alexandre DERUMIER" <aderumier at odiso.com>, pve-devel at pve.proxmox.com 
Envoyé: Mardi 7 Janvier 2014 09:39:48 
Objet: Re: [pve-devel] RFC : qemu-server : add cpu_hotplug 

Hi Alexendre, 

Am 07.01.2014 09:36, schrieb Alexandre DERUMIER: 
>>> I don't known if the event is the same for kvm cpu hotplug. 
> 
> This udev rule is working (I take it from opensuse and rhel) 
> 
> 80-hotplug-cpu-mem.rules 
> 
> # Hotplug physical CPU 
> SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", \ 
> ATTR{online}="1" 
> 
> # Hotplug physical memory 
> SUBSYSTEM=="memory", ACTION=="add", TEST=="state", ATTR{state}=="offline", \ 
> ATTR{state}="online" 
> 
> 
> Don't work with debian wheezy (3.10 kernel), but work with jessie. (So maybe it's udev version related). 
> Works out of the box with rhel7 guest. 

You mean wheezy 3.2 Kernel? It does not have a 3.10 Kernel. 

Does this mean, that memory hotplug works too? 

Stefan 


> 
> ----- Mail original ----- 
> 
> De: "Alexandre DERUMIER" <aderumier at odiso.com> 
> À: pve-devel at pve.proxmox.com 
> Envoyé: Mardi 7 Janvier 2014 07:06:48 
> Objet: Re: [pve-devel] RFC : qemu-server : add cpu_hotplug 
> 
>>> (I'm not sure,but maybe this could be done auto with qemu-ga) 
> 
> I see some guy doing it with qemu-ga, but maybe it's also possible with a clean udev rule in guest. 
> 
> 
> xen is doing it with this udev rules 
> 
> SUBSYSTEM=="cpu",ACTION=="add",RUN+="/bin/sh -c '[ ! -e /sys$devpath/online ] || echo 1 > /sys$devpath/online'" 
> 
> I don't known if the event is the same for kvm cpu hotplug. 
> 
> 
> 
> ----- Mail original ----- 
> 
> De: "Alexandre Derumier" <aderumier at odiso.com> 
> À: pve-devel at pve.proxmox.com 
> Envoyé: Lundi 6 Janvier 2014 17:56:46 
> Objet: [pve-devel] RFC : qemu-server : add cpu_hotplug 
> 
> Theses patches are cpu_hotplug feature. 
> 
> unplug is not yet available in current qemu. 
> 
> This introduce a new "maxcpus" config value. 
> 
> If maxcpus is defined, sockets should be set to 1, as we can only hotplug 1cpu/core step by step, up to maxcpus value. 
> 
> Tested under debian with kernel 3.2. 
> 
> cpu need to be enabled after hotplug in guest with "echo 1 > /sys/devices/system/cpu/cpuX/online". 
> (I'm not sure,but maybe this could be done auto with qemu-ga) 
> 
> 
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