Re: [PATCH v4 0/8] KVM paravirt remote flush tlb

Avi Kivity
2012-09-03T15:27:17Z

On 09/03/2012 05:33 PM, Avi Kivity wrote:
> On 08/21/2012 02:25 PM, Nikunj A. Dadhania wrote:
>>
>> kernbench(lower is better)
>> ==========================
>> base pvflushv4 %improvement
>> 1VM 48.5800 46.8513 3.55846
>> 2VM 108.1823 104.6410 3.27346
>> 3VM 183.2733 163.3547 10.86825
>>
>> ebizzy(higher is better)
>> ========================
>> base pvflushv4 %improvement
>> 1VM 2414.5000 2089.8750 -13.44481
>> 2VM 2167.6250 2371.7500 9.41699
>> 3VM 1600.1111 2102.5556 31.40060
>>
>
> The regression is worrying. We're improving the contended case at the
> cost of the non-contended case, this is usually the wrong thing to do.
> Do we have any clear idea of the cause of the regression?

For that matter, why do we get an improvement in the 1VM kbuild test?
All vcpus should be running most of the time, barring I/O thread activity.

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