Re: [Xen-devel] [RFC PATCH 21/24] ARM: vITS: handle INVALL command

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

On Tue, 2016-12-06 at 14:01 -0800, Stefano Stabellini wrote:
> On Tue, 6 Dec 2016, Stefano Stabellini wrote:
> > 
> > moving a vCPU with interrupts assigned to it is slower than moving
> > a
> > vCPU without interrupts assigned to it. You could say that the
> > slowness is directly proportional do the number of interrupts
> > assigned
> > to the vCPU.
> 
> To be pedantic, by "assigned" I mean that a physical interrupt is
> routed
> to a given pCPU and is set to be forwarded to a guest vCPU running on
> it
> by the _IRQ_GUEST flag. The guest could be dom0. Upon receiving one
> of
> these physical interrupts, a corresponding virtual interrupt (could
> be a
> different irq) will be injected into the guest vCPU.
> 
> When the vCPU is migrated to a new pCPU, the physical interrupts that
> are configured to be injected as virtual interrupts into the vCPU,
> are
> migrated with it. The physical interrupt migration has a cost.
> However,
> receiving physical interrupts on the wrong pCPU has an higher cost.
>
Yeah, I got in what sense you said "assigned", but thanks anyway for
this clarification. It indeed makes the picture more clear (even just
FTR) :-)

Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

Attachment: signature.asc
Description: This is a digitally signed message part

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel