This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] IRQ affinity: Xen view different from pvops (konrad-pcif

To: "Dante Cinco" <dantecinco@xxxxxxxxx>
Subject: Re: [Xen-devel] IRQ affinity: Xen view different from pvops (konrad-pcifront) domU
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Thu, 11 Nov 2010 13:22:02 +0000
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 11 Nov 2010 05:22:47 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <AANLkTi=04eGuAUKwtSSGhQW9Sxpv18u3Ubz3TWex6Ts4@xxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTimFzT6AFb14XZQ4NzBQYsJAEEGb5uJYTU3Gv-8j@xxxxxxxxxxxxxx> <4CDA622D020000780002165E@xxxxxxxxxxxxxxxxxx> <AANLkTi=04eGuAUKwtSSGhQW9Sxpv18u3Ubz3TWex6Ts4@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> On 10.11.10 at 21:18, Dante Cinco <dantecinco@xxxxxxxxx> wrote:
> After seeing your response (cs 21625, x86: IRQ affinity should track
> vCPU affinity), I installed the latest xen-unstable-4.1 (cs 22382) and
> the result is the same --- IRQ affinity in Xen is set to all F's after
> explicitly setting the IRQ smp_affinity in domU to a specific CPU. I
> do have the VCPUs assigned to domU pinned to PCPUs on a one-to-one
> basis (VCPU0 -> PCPU0, VCPU1 -> PCPU1, etc.).

You may need to do some debugging then to find out what's not
working in your case.

> My system has 24 PCPUs (dual socket X5650 Xeon/6-core Westmere) but
> I'm only assigning the first 16 CPUs to domU and the VCPUs are pinned
> to their respective PCPU. The part I don't understand is if the IRQ
> affinity per Xen (all F's) is correct, how does the interrupt get
> handled if it is directed to a PCPU that is not assigned/pinned to a
> VCPU in domU?

Since the guest handles event channel signals only, all it takes
is binding the event channel to the correct vCPU. When the
channel gets signaled, that vCPU will call the handler.


Xen-devel mailing list