Re: cpu hotplug

[Gleb Natapov <gleb@redhat.com>]

On Sun, Sep 19, 2010 at 01:32:28PM +0200, Conrad Wood wrote:
> On Sun, 2010-09-19 at 13:13 +0200, Gleb Natapov wrote:
> > On Sun, Sep 19, 2010 at 01:09:39PM +0200, Conrad Wood wrote:
> > > On Sun, 2010-09-19 at 12:46 +0200, Gleb Natapov wrote:
> > > [...]
> > > > > But... why does the command "info cpus" in the monitor report all cpus
> > > > > apart from CPU0 as (halted) ?
> > > > > 
> > > > Because they are halted? Run multiple cpu hogs in the guest and see if
> > > > cpus will still be halted as reported by monitor. Also kvm-72 is so
> > > > ancient that I am not sure it reports cpu state correctly in monitor at
> > > > all.
> > > > 
> > > > --
> > > fair enough, upgraded to 0.12.5, same results.
> > > 
> > > tried a cpu-hog (small loop forking 5 times and each fork doing some
> > > integer arithmetics for a while) - no change in info cpus
> > > 
> > > thank you, but I still don't get it ;-)
> > > 
> > At what rip are they halted? Try to run without kvm and see if the
> > result is the same. Can you provide output of "info cpus" here?
> > Are you using qemu-kvm or qemu BTW?
> 
> I am using qemu-kvm (debian package Version: 0.12.5+dfsg-3).
> Here's the "info cpus"  with and without kvm acceleration.
> basically qemu shows the behavior I'd expect, kvm does not. Or do I
> misunderstand something?
> 
No you are not. So your qemu-kvm version has cpu state reporting bug too. It is
not serious bug, just annoying. pc shows that otherwise everything is
working as expected.

> I wonder. if this is relevant: The host only has a single cpu, with 4
> cores, I had expected those to be seen as cpus in the guest, similar how
> linux lists each core as a cpu in the host.
Guest and host has different cpu topology.

--
			Gleb.