Re: [PATCH 2/2] x2apic, cluster: use all the members of one clusterspecified in the smp_affinity mask for the interrupt desintation

From: Cyrill Gorcunov
Date: Tue May 22 2012 - 13:39:26 EST


On Tue, May 22, 2012 at 10:21:15AM -0700, Suresh Siddha wrote:
> On Tue, 2012-05-22 at 09:04 +0200, Ingo Molnar wrote:
> > * Suresh Siddha <suresh.b.siddha@xxxxxxxxx> wrote:
> >
> > > If the HW implements round-robin interrupt delivery, this
> > > enables multiple cpu's (which are part of the user specified
> > > interrupt smp_affinity mask and belong to the same x2apic
> > > cluster) to service the interrupt.
> >
> > Could/should we do something similar for regular APICs as well?
> > They too support masks and LowestPrio delivery - and doing that
> > will increase test coverage rather significantly.
>
> Existing logical flat xapic mode already takes advantage of this today.

Suresh, should not we tune up es7000_cpu_mask_to_apicid code to return
apicid with a cluster number and ORed logical apicid part as done for
x2apic, or the way it resturns apicid now was done by a purpose?

Cyrill
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