Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757522AbXLSRKA (ORCPT ); Wed, 19 Dec 2007 12:10:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756056AbXLSRJu (ORCPT ); Wed, 19 Dec 2007 12:09:50 -0500 Received: from il.qumranet.com ([82.166.9.18]:38796 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752899AbXLSRJu (ORCPT ); Wed, 19 Dec 2007 12:09:50 -0500 Message-ID: <4769505C.5020309@qumranet.com> Date: Wed, 19 Dec 2007 19:09:48 +0200 From: Avi Kivity User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: dor.laor@qumranet.com CC: Amit Shah , kvm-devel@lists.sourceforge.net, linux-kernel , Avi Kivity , Gerd Hoffmann Subject: Re: [kvm-devel] Guest kernel hangs in smp kvm for older kernelsprior to tsc sync cleanup References: <47680173.6060606@qumranet.com> <47692A47.4040803@argo.co.il><5d6222a80712190732h515a63e6y49c64c0f572f044@mail.gmail.com> <200712192225.53748.amit.shah@qumranet.com> <47694F35.6070401@qumranet.com> In-Reply-To: <47694F35.6070401@qumranet.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1029 Lines: 30 Dor Laor wrote: >> > > >> > > vmx (and svm) allow us to add an offset to the physical tsc. We >> set it >> > > on startup to -tsc (so that an rdtsc on boot would return 0), and >> > > massage it on vcpu migration so that guest rdtsc is monotonic. >> > > >> > > The net effect is that tsc on a vcpu can experience large forward >> jumps >> > > and changes in rate, but no negative jumps. >> > >> > Changes in rate does not sound good. It's possibly what's screwing up >> > my paravirt clock implementation in smp. >> >> Do you mean in the case of VM migration, or just starting them on a >> single >> host? >> > It's the cpu preemption stuff on local host and not VM migration No, migrating a vcpu to another cpu. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/