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] ac_timer: time to say goodbye?

To: "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] ac_timer: time to say goodbye?
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Mon, 23 May 2005 21:12:05 +0100
Delivery-date: Mon, 23 May 2005 20:11:27 +0000
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/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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcVf0fuq2Yt5GIupSrGQlgxKTX+ysQAAPVlg
Thread-topic: [Xen-devel] ac_timer: time to say goodbye?
 

> It appears that the ac_timer code is not used very much 
> anymore.  (Not that it's not used at all, just not very 
> much... grep for ac_timer.)  It's kind of a heavyweight 
> mechanism for a hypervisor... I wonder if it might be 
> possible to dispense with it entirely?
> 
> The reason I ask now is that, as part of the ia64 CONFIG_VTI 
> checkin, some new timer code got added that makes use of 
> ac_timer and I'm concerned that this might be a step in the 
> wrong direction.
> 
> As domains more completely manage their own timer interrupts, 
> the only use for time in Xen itself is for time-slicing 
> domains, correct?
> 
> Should ac_timer be removed and replaced by a lighter weight 
> mechanism, or at least its use deprecated?

Heavy weight? It's a basic heap (priority queue) implementation. 
Seems to me like a perfectly sensible thing to have in a hypervisor, and
its used extensively by all the schedulers.

Thanks,
Ian


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

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