From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753083AbXCPIkr (ORCPT ); Fri, 16 Mar 2007 04:40:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753122AbXCPIkr (ORCPT ); Fri, 16 Mar 2007 04:40:47 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:40973 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753083AbXCPIkp (ORCPT ); Fri, 16 Mar 2007 04:40:45 -0400 Date: Fri, 16 Mar 2007 09:38:28 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Dan Hecht , dwalker@mvista.com, cpufreq@lists.linux.org.uk, Linux Kernel Mailing List , Con Kolivas , Chris Wright , Virtualization Mailing List , john stultz , Thomas Gleixner , paulus@au.ibm.com, schwidefsky@de.ibm.com, Rik van Riel Subject: Re: Stolen and degraded time and schedulers Message-ID: <20070316083828.GA22168@elte.hu> References: <1173816769.22180.14.camel@localhost> <45F70A71.9090205@goop.org> <1173821224.1416.24.camel@dwalker1> <45F71EA5.2090203@goop.org> <45F74515.7010808@vmware.com> <45F77C27.8090604@goop.org> <45F846AB.6060200@vmware.com> <45F84E39.7030507@goop.org> <20070314203826.GA15394@elte.hu> <45F86247.40109@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45F86247.40109@goop.org> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Jeremy Fitzhardinge wrote: > Ingo Molnar wrote: > > touching the 'timer tick' is the wrong approach. 'stolen time' only > > matters to the /scheduler tick/. So extend the hypervisor interface to > > allow the injection of 'virtual' scheduler tick events: via the use of a > > special clockevents device - do not change clockevents itself. > > I didn't. I was using sloppy terminology: I hang the stolen time > accounting off the Xen timer interrupt routine, just so that it gets > run every now and again. i dont understand: how are you separating 'stolen time' drifts from events generated for absolute timeouts? > I suppose I could explicitly hook stolen time accounting into the > scheduler, but its not obvious to me that it's necessary. right now i dont see any clean way to solve this problem without having two clockevents drivers: one for the scheduler, one for timer events. Ingo