Re: [libvirt-users] setvcpus libvirt 1.2.9

Am 05.11.14 14:48, schrieb Eric Blake: > On 11/05/2014 01:20 PM, Thomas Stein wrote: >> Am 05.11.14 11:48, schrieb Martin Kletzander: >>> On Wed, Nov 05, 2014 at 11:35:37AM +0100, Thomas Stein wrote: >>>> Hello. >>>> >>>> I'm struggeling a little bit with the setvcpus command. I'm trying now >>>> to get this running for a linux VM. Here is what i have: >>>> >>>> <vcpu placement='auto' current='2'>4</vcpu> > > This is one case where xen may be a bit more powerful than current qemu > support. Xen supports booting a guest with a promise of a maximum cpu > larger than what it boots with; but I don't know that qemu does that > well yet. For now, with qemu, you pretty much have to boot with all > cpus enabled, then after the guest is up and running, disable the cpus > you don't plan to use right away. CPU hotplug/hot-unplug is still a > work in progress in qemu (for example, some versions of qemu support > hotplug but not hot-unplug). I haven't played much with it myself to > know what minimum version of libvirt and qemu will do what you want, so > you may have to do some experimentation. Thanks. I let you know if my experiments lead to some discoveries.