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[Xen-devel] RE: Interrupt to CPU routing in HVM domains - again

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] RE: Interrupt to CPU routing in HVM domains - again
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Fri, 5 Sep 2008 20:13:23 +1000
Cc: bart brooks <bart_brooks@xxxxxxxxxxx>
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Thread-topic: Interrupt to CPU routing in HVM domains - again
> The only thing I can think of (and should certainly be checked!) is
> some of your event channels are erroneously getting bound to vcpu !=
> Are
> you running an irq load balancer or somesuch? Obviously event channels
> bound
> to vcpu != 0 will now never be serviced, whereas before your changes
> would probabilistically 'get lucky'.

In allocating event channels, I'm doing EVTCHNOP_alloc_unbound and then
passing the returned event channel number to Dom0 via xenbus. Is there
anything else I need to do? Do I need a specific hypercall to bind the
event channel to cpu 0 only? I'll check the 'unmodified drivers'

The thing is, my performance testing has shown good results for SMP
(vcpus=4) and UP, but Bart has reported that he only gets good
performance when he checks the vcpu_info for the cpu that the interrupt
has been triggered on.


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