Re: [libvirt] RFC: add <currentVcpu> element

On 09/27/2010 11:20 AM, Eric Blake wrote: >> >>Another question I had, is there a way in QEmu to specifiy a different >>cpu count from the -smp indicating the startup count ? > >I wish I knew off-hand, as it would make it easier for me to implement >when I get to that part of the patch series :) But even if there isn't, >I think that starting with the maximum via -smp and immediately after >hot-unplugging to the current count is better than nothing. Answering my own question: with qemu 0.12.5, 'qemu -help' lists: -smp n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets] set the number of CPUs to 'n' [default=1] maxcpus= maximum number of total cpus, including offline CPUs for hotplug etc. So it looks like '-smp 1,maxcpus=2' maps nicely to <vcpu current='1'>2</vcpu>. But per tests/qemuhelpdata, qemu 0.11.0 lacks this, so I also have to code up a qemu feature test.