Gleb Natapov <g...@redhat.com> writes: > On Thu, Sep 13, 2012 at 09:06:29AM -0500, Anthony Liguori wrote: >> "Daniel P. Berrange" <berra...@redhat.com> writes: >> >> I think it's better for QEMU to talk to qemu-ga. We can tell when a large >> period of time has passed in QEMU because we'll accumulate a large >> number of missed ticks. >> > With RTC configured to use vm clock we will not.
Not for host suspend. For stop and live migration, we stop vm_clock. But QEMU isn't aware of host suspend so vm_clock cannot be stopped. >> This could happen because of stop, host suspend, live migration to a >> file, etc. >> >> It's much easier for us to call into qemu-ga to do the time correction >> whenever this event occurs than to try and have libvirt figure out when >> it's necessary. > And if guest does not have qemu-ga what is better inject interrupts like > crazy for next 2 minutes or leave guest with incorrect time? Yes, at least that's fixable by the end-user. QEMU consuming 100% CPU for a prolonged period of time isn't fixable. Regards, Anthony Liguori > >> >> We know exactly when it's necessary, libvirt would need to guess. >> >> Yes, we could generate a QMP event when a large skew was dedicated, but >> I think this could happen often enough that it would be problematic. >> Since QEMU is already implementing policy doing timer catchup in the >> first place, I think we probably should own time catchup policy entirely. >> >> Regards, >> >> Anthony Liguori >> >> > >> > Regards, >> > Daniel >> > -- >> > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ >> > :| >> > |: http://libvirt.org -o- http://virt-manager.org >> > :| >> > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ >> > :| >> > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc >> > :| > > -- > Gleb.
