RE: [Xen-devel] RE: Rather slow time of Ping in Windows with GPL PVdriver

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

> 
> Do you mean if we discard KeSetTargetProcessorDpc(&xi->rx_dpc, 0) ,
the
> interrupts
> will be processed across on different VCPUS, but will cause serious
> performance issue?
> Where could I find the releated docs?
> 
> So actually we need do KeSetImportanceDpc(&xi->rx_dpc, HighImportance)
to
> solve
> ping problem.  Though performance is not the best, but it should not
decrease,
> right?
> 

In my testing, without the KeSetTargetProcessorDpc, iperf would give
inconsistent results, which I assume is because packets were being
delivered to NDIS out of order.

KeSetImportanceDpc(HighImportance) should resolve the 15ms response time
you were seeing as the DPC will be immediately scheduled on the other
processor, rather than scheduled some time later.

James

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