Counting VCPU instructions

Counting VCPU instructions

[Abhishek Saksena]

Hi guys,
Is ther a way to count how many instruction VCPU (KVM) executed? Say
between between two IO/mmio operations.
Is there any KVM API for this?

Other thing which I am not sure how KVM kerenel is synconrinized with
Qemu kernel? Can somebody explain this?

Thanks

Abhishek

Re: Counting VCPU instructions

[Avi Kivity]

Abhishek Saksena wrote:
> Hi guys,
> Is ther a way to count how many instruction VCPU (KVM) executed? Say
> between between two IO/mmio operations.
> Is there any KVM API for this?
>
>   

While it's possible in theory using the hardware performance counters, 
no one has implemented this.

> Other thing which I am not sure how KVM kerenel is synconrinized with
> Qemu kernel? Can somebody explain this?
>   

What's the qemu kernel?

-- 
error compiling committee.c: too many arguments to function

Re: Counting VCPU instructions

[Avi Kivity]

(restoring cc)

Abhishek Saksena wrote:
>>> Other thing which I am not sure how KVM kerenel is synconrinized with
>>> Qemu kernel? Can somebody explain this?
>>>
>>>       
>> What's the qemu kernel?
>>     
>
> Just qemu. Qemu has it's own timers how they are synced up with KVM?
> For example if the guest is getting too far ahead, we need to slow it down.
>   

Guest getting too far ahead of what?  Why would we want to slow down a 
guest?

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.