From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 0/3] KVM clock, new iteration Date: Fri, 11 Jan 2008 09:49:51 -0600 Message-ID: <4787901F.7030208@codemonkey.ws> References: <12000570563874-git-send-email-gcosta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, jeremy-TSDbQ3PG+2Y@public.gmane.org, avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org To: Glauber de Oliveira Costa Return-path: In-Reply-To: <12000570563874-git-send-email-gcosta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Glauber de Oliveira Costa wrote: > Hi folks, > > A lot of time has been elapsed since I last sent a version of kvm clock, > with a lot of things in the middle, including my vacations and a nasty bug > in the clock itself ;-) > > Here it is a new version. I'm following avi's last suggestion of using an msr > to make it more migration-proof. If it's not approved, we can easily switch back > to the hypercall mechanism. That's the easy part ;-) > > Clock updates are done every time we're scheduled. It is _not_ enough to check > if we're changing cpus, because the tsc will change its frequency when the cpu is > idle (if using the mwait idle). So after a long idle period, one cpu will end up stepping > ahead causing a backward time (remember the bug I talked about? :-) ) > > As I fell it ready for inclusion (which obviously does not mean it is perfect, nor that > I don't value any further comments ), I'm also posting the userspace patches in a separate > series that will follow shortly. > > This patch series is looking good. I like the switch to an MSR. Regards, Anthony Liguori ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace