Re: Host latency peaks due to kvm-intel

[Avi Kivity <avi@redhat.com>]

On 07/26/2009 05:34 PM, Jan Kiszka wrote:
> Avi Kivity wrote:
>    
>> On 07/24/2009 12:41 PM, Jan Kiszka wrote:
>>      
>>> Jan (who is now patching his guest to avoid wbinvd where possible)
>>>
>>>
>>>        
>> Is there ever a case where it is required?  What about under a
>> hypervisor (i.e. check the hypervisor enabled bit).
>>
>>      
>
> Reminds me of the discussion in '07 when I first stumbled over this :) :
> Yes, the bochs bios could safely skip the wbinvd in qemu mode. But that
> won't safe us from Linux and - far more problematic - Windows or any
> binary-only guest which think they have to issue it.
>
> One may the close eyes, fire up the guest and then start the
> time-critical host application in the hope that the guest remains calm
> as long as it's up and running. But, well...
>    

Given that it's now '09, how critical is the problem?  Don't most cpus 
have vwbinvd now?

If so, the real-time management application can simply refuse to run on 
such an old processor.

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