From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH 04 of 11 v4] xen: sched_credit: let the scheduler know about node-affinity Date: Mon, 18 Mar 2013 13:58:55 +0000 Message-ID: <51471D9F.3070707@eu.citrix.com> References: <9b35836856e2d1fe9adf.1363314646@hit-nxdomain.opendns.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9b35836856e2d1fe9adf.1363314646@hit-nxdomain.opendns.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Dario Faggioli Cc: Marcus Granado , Dan Magenheimer , Ian Campbell , Anil Madhavapeddy , Andrew Cooper , Juergen Gross , Ian Jackson , Xen-Devel , Jan Beulich , Daniel De Graaf , Matt Wilson List-Id: xen-devel@lists.xenproject.org On 15/03/13 02:30, Dario Faggioli wrote: > As vcpu-affinity tells where VCPUs must run, node-affinity tells > where they prefer to. While respecting vcpu-affinity remains mandatory, > node-affinity is not that strict, it only expresses a preference, > although honouring it will bring significant performance benefits > (especially as compared to not having any affinity at all). > > This change modifies the VCPUs load balancing algorithm (for the > credit scheduler only), introducing a two steps logic. During the > first step, we use both the vcpu-affinity and the node-affinity > masks (by looking at their intersection). The aim is giving precedence > to the PCPUs where the domain prefers to run, as expressed by its > node-affinity (with the intersection with the vcpu-afinity being > necessary in order to avoid running a VCPU where it never should). > If that fails in finding a valid PCPU, the node-affinity is just > ignored and, in the second step, we fall back to using cpu-affinity > only. > > Signed-off-by: Dario Faggioli > Acked-by: Juergen Gross Acked-by: George Dunlap