Re: [PATCH] time,virt: resync steal time when guest & host lose sync

Rik van Riel
2016-08-15T15:00:54Z

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On Mon, 2016-08-15 at 16:53 +0800, Wanpeng Li wrote:
> 2016-08-12 23:58 GMT+08:00 Rik van Riel <riel@redhat.com>:
> [...]
> > Wanpeng, does the patch below work for you?
>
> It will break steal time for full dynticks guest, and there is a
> calltrace of thread_group_cputime_adjusted call stack, RIP is
> cputime_adjust+0xff/0x130.

How?  This patch is equivalent to passing ULONG_MAX to
steal_account_process_time, which you tried to no ill
effect before.

Do you have the full call trace?

> > Subject: time,virt: do not limit steal_account_process_time
> >
> > When a guest is interrupted for a longer amount of time, missed
> > clock
> > ticks are not redelivered later. Because of that, we should not
> > limit
>
> Interesting, so do we need to add a feature like lapic timer
> interrrupt coalescing in kvm? There is a RTC interrupt coalescing in
> qemu to handle the scenario you mentioned for windows guest, if we
> need a similar feature for linux guest? Paolo, Radim? I can try it if
> you think it's valuable. :)
>
> Regards,
> Wanpeng Li
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