Re: Seeking a KVM benchmark

Wanpeng Li
2014-11-17T12:14:33Z

Hi Paolo,
On 11/17/14, 8:04 PM, Paolo Bonzini wrote:
>
> On 17/11/2014 13:00, Wanpeng Li wrote:
>> Sorry, maybe I didn't state my question clearly. As Avi mentioned above
>> "In VMX we have VPIDs, so we only need to flush if EFER changed between
>> two invocations of the same VPID", so there is only one VPID if the
>> guest is UP, my question is if there need a TLB flush when guest's EFER
>> has been changed?
> Yes, because the meaning of the page table entries has changed.

So both VMX EFER writes and non-VMX EFER writes cause a TLB flush for UP
guest, is there still a performance improvement in this case?

Regards,
Wanpeng Li

>
> Paolo