From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH] raise tsc clocksource rating Date: Mon, 29 Oct 2007 16:33:34 -0700 Message-ID: <47266DCE.1070309@goop.org> References: <11936994092607-git-send-email-gcosta@redhat.com> <1193697734.9793.86.camel@bodhitayantram.eng.vmware.com> <20071029224852.GA27547@elte.hu> <47266431.1010500@goop.org> <20071029225528.GA31293@elte.hu> <47266A00.4040408@goop.org> <20071029232140.GA10518@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Zachary Amsden , kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Dan Hecht , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity , Glauber de Oliveira Costa , Glauber de Oliveira Costa , Garrett Smith To: Ingo Molnar Return-path: In-Reply-To: <20071029232140.GA10518-X9Un+BFzKDI@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 Ingo Molnar wrote: > i dont remember us having discussed this before, ever. If there's any > "fight" about monotonicity and SMP then it would be a pretty onesided > affair, with you being beaten up seriously ;-) > This is part of Xen's ABI, so it isn't easily changed. You're right that getting monotonicity is a pretty ugly affair of doing something like "if (now < previous_return) return ++previous_return;", but its better than using the tsc. (Last time around, it was "Xen can't use the tsc because it can't ever be used as a stable timebase" - though I don't think that was you specifically.) J ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/