Re: [patch 00/13] RFC: out of sync shadow

David S. Ahern
2008-09-12T18:19:28Z

Marcelo Tosatti wrote:
> On Fri, Sep 12, 2008 at 09:12:03AM -0600, David S. Ahern wrote:
>>
>> Marcelo Tosatti wrote:
>>> On Thu, Sep 11, 2008 at 10:05:12PM -0600, David S. Ahern wrote:
>>>
>>> David,
>>>
>>> Please reload the kvm-intel module with "bypass_guest_pf=0" option.
>>>
>>>
>> DOH. You mentioned that in your description, and I forgot to disable it.
>> Works fine now.
>>
>> Guest behavior is amazing. After 30 min of uptime, kscand shows only
>> 17secs of cpu usage. Before, kscand was hitting over a minute after
>> about 10 minutes of uptime.
>
> Great. Note that its not fully optimized for the RHEL3 highpte kscand
> case, which calls invlpg for present pagetable entries.
>
> The current patchset simply invalidates the shadow on invlpg, meaning
> that the next access will cause a pagefault exit.
>
> It can instead read the guest pte and prefault, saving one exit per
> test-and-clear-accessed operation.
>

Meaning performance will get even better? Sweet.

david