Re: [PATCH 04/17] Fix deep C-state TSC desynchronization

Zachary Amsden
2010-06-16T18:43:46Z

On 06/15/2010 10:10 PM, Jason Wang wrote:
> Zachary Amsden wrote:
>
>> When CPUs with unstable TSCs enter deep C-state, TSC may stop
>> running. This causes us to require resynchronization. Since
>> we can't tell when this may potentially happen, we assume the
>> worst by forcing re-compensation for it at every point the VCPU
>> task is descheduled.
>>
>>
>>
> Is there any method to do the compensation on host TSC when recovering
> from C-state? It should be simpler than do it on guest TSC.
>

Actually, yes, we could re-calibrate from HPET. Considering this patch
is already broken, maybe that's a better idea.