Re: [RFC 0/4] KVM in-kernel PM Timer implementation

David S. Ahern
2010-12-14T19:54:52Z

On 12/14/10 12:49, Anthony Liguori wrote:
> But that doesn't tell you what the impact is in real world workloads.
> Before we start pushing all device emulation into the kernel, we need to
> quantify how often gettimeofday() is really called in real workloads.

The workload that inspired that example program at its current max load
calls gtod upwards of 1000 times per second. The overhead of
gettimeofday was the biggest factor when comparing performance to bare
metal and esx. That's why I wrote the test program --- boils a complex
product/program to a single system call.

David

>
> Regards,
>
> Anthony Liguori
>
>> What's the relative speed of the in-kernel pmtimer compared to the PIT?
>>
>> David
>>
>