Re: paravirt clock stil causing hangs in kvm-65

[Marcelo Tosatti <mtosatti@redhat.com>]

On Sat, Apr 19, 2008 at 01:22:28PM -0300, Glauber Costa wrote:
> >  I've been able to reproduce the problem. Symptoms are that when using
> >  NOHZ vcpu0 LAPIC timer is ticking far less than the others (apparently vcpu0
> >  is the only one ticking "correctly"):
> >
> >
> >  nohz=on with kvmclock
> >  [root@localhost ~]# cat /proc/timer_stats | grep apic
> >   13214,  8590 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   13214,  8589 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   13211,  8588 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   389,  8587 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >
> >  nohz=off
> >   3253,  8672 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   2876,  8673 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   2543,  8674 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   2179,  8675 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >
> >  no-kvmclock
> >   1017,  8808 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   1577,  8809 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   1708,  8807 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >   1812,  8806 qemu-system-x86  apic_mmio_write (apic_timer_fn)
> >
> >
> >  Glauber will start looking at this next week.
> >
> >
> >
> 
> >From what me and marcelo discussed, I think there's a possibility that
> it has marginally something to do with precision of clock calculation.
> Gerd's patches address that issues. Can somebody test this with those
> patches (both guest and host), while I'm off ?

Haven't seen Gerd's guest patches ? 

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