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

Re: [Xen-devel] status of cpufreq code support

To: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] status of cpufreq code support
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 2 Aug 2006 15:11:39 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Wed, 02 Aug 2006 07:12:01 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <44D0CD95.76E4.0078.0@xxxxxxxxxx>
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <44D0CD95.76E4.0078.0@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

On 2 Aug 2006, at 15:06, Jan Beulich wrote:

Can someone give me an understanding what the current position on allowing dom0 to manipulate the CPU frequency is? The config options haven't been disabled for a while, but when I recently did a build there were still symbols missing for some of the drivers. Also, I continue to believe that playing with the CPU frequency behind the back of Xen isn't the
best idea.

Thanks, Jan

I've been thinking about it and come to the conclusion that the right thing is to let dom0 fiddle with the CPU frequencies, subject to: 1. It should have a 1:1 mapping to physical CPUs (i.e., VCPU0 always runs on CPU0, VCPU1 on CPU1, etc.). Preferably we'd also pass real topology info to dom0 too, so that it can do the right thing for multi-core and hyperthreads. 2. We need an interface for dom0 to tell Xen that the speed is changing, so that scale factors can be updated.

 -- Keir


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

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