From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [PATCH 0/6] In kernel PIT patch
Date: Wed, 05 Mar 2008 17:05:07 -0600
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Cc: kvm-devel@lists.sourceforge.net, Avi Kivity <avi@qumranet.com>
To: dor.laor@qumranet.com
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Dor Laor wrote:
> On Wed, 2008-03-05 at 19:30 +0200, Avi Kivity wrote:
>   
>>
>> Playing a movie is better than any benchmark; it reflects actual user 
>> experience in a real and important use case.  Benchmarks are substitutes 
>> for real use cases, not the goal of the optimization.
>>
>>     
>
> I forgot to mention that the benchmark is measuring time drift in the
> guest. Playing a movie in winxp changes the guest clock frequency from
> 100HZ to 1000HZ, thus causing a 250HZ host to coalesce pit irqs.
>
> So good pic & pit combination can handle guest multimedia without drifts
> while insufficient implementation just can't.
>   

I'll try out these patches in the next day or so.  Is the expectation 
that Standard HAL + in-kernel APIC/PIT will have smoother playback than 
ACPI HAL w/o in-kernel APIC/PIT?  I presume that the ACPI HAL is 
unaffected by in-kernel PIT?

Regards,

Anthony Liguori



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