WARNING - OLD ARCHIVES

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/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Ping: c/s 20526 (tools: avoid cpu over-commitment if numa=on

To: <andre.przywara@xxxxxxx>
Subject: [Xen-devel] Ping: c/s 20526 (tools: avoid cpu over-commitment if numa=on)
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Wed, 13 Jan 2010 08:15:08 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Wed, 13 Jan 2010 00:15:34 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Andre,

I'm afraid this change isn't really correct:

>+                cores_per_node = info['nr_cpus'] / info['nr_nodes']
>+                nodes_required = (self.info['VCPUs_max'] + cores_per_node - 
>1) / cores_per_node

Simply using cores_per_node (as calculated here) as a divisor is bound
to cause division-by-zero issues, namely when limiting the number of
CPUs on the Xen command line (maxcpus=). I'm not sure though, what
a reasonable solution to this might look like, since cores-per-node is
a meaningless thing in an artificial setup like this, and may also be
meaningless in asymmetric configurations. So perhaps we really need
to iterate over nodes while summing up the number of CPUs they
have until the number of needed vCPU-s was reached.

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>