Re: Hangs

Daniel P. Berrange
2008-11-21T21:01:43Z

On Fri, Nov 21, 2008 at 09:29:43PM +0100, Roland Lammel wrote:
> On Fri, Nov 21, 2008 at 4:55 PM, Glauber Costa <glommer@redhat.com> wrote:
> > On Thu, Nov 20, 2008 at 02:56:00AM +0100, Marcelo Tosatti wrote:
> >>
> >> Why are you using -no-acpi? Perhaps switch the guest to acpi_pm to isolate
> >> kvm-clock issues?
>
> I've changed one guest to use acpi and use the acpi_pm clock source.
>
> Running now with:
> /usr/local/bin/qemu-system-x86_64 -S -M pc -m 500 -smp 1 -name bit
> -monitor pty -no-acpi -boot c -drive
> file=/var/kvm/bit.img,if=virtio,index=0,boot=on -net
> nic,macaddr=24:42:53:21:52:45,vlan=0,model=virtio -net
> tap,fd=11,script=,vlan=0,ifname=vnet0 -serial tcp:127.0.0.1:50401
> -parallel none -usb -vnc 0.0.0.0:45001
>
> Actually I had similar problems when using kvm-72 and acpi, and after
> switching to libvirt for configuration it automatically changed to
> no-acpi which I just left that way to try it. I've read mixed
> recommendaction concerning ACPI.

FYI, libvirt allows you to turn ACPI on or off. In the XML document,
the top level <domain> tag can contains a set of features, one of
which is ACPI, eg.

<domain type='kvm'>
<name>foo</name>
.....
<features>
<acpi/>
</features>
....
</domain>

If the '<acpi/>' tag is left out, libvirt will add -no-acpi to QEMU
command line.

For more information check out the docs here:

http://libvirt.org/formatdomain.html#elementsFeatures

> So should acpi be enabled generelly (for modern kernels and systems)?
> Should ntpd be running on the guests, or just the host when using acpi_pm?

The virt-install & virt-manager tools will enable ACPI by default for
nearly all OS, except for a couple of very old Windows which don;t
commonly work

Regards,
Daniel
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