Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751690Ab0HTRav (ORCPT ); Fri, 20 Aug 2010 13:30:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36712 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751208Ab0HTRar (ORCPT ); Fri, 20 Aug 2010 13:30:47 -0400 Date: Fri, 20 Aug 2010 14:30:38 -0300 From: Glauber Costa To: Zachary Amsden Cc: kvm@vger.kernel.org, Avi Kivity , Marcelo Tosatti , Thomas Gleixner , John Stultz , linux-kernel@vger.kernel.org Subject: Re: [KVM timekeeping 10/35] Fix deep C-state TSC desynchronization Message-ID: <20100820173038.GE2937@mothafucka.localdomain> References: <1282291669-25709-1-git-send-email-zamsden@redhat.com> <1282291669-25709-11-git-send-email-zamsden@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1282291669-25709-11-git-send-email-zamsden@redhat.com> X-ChuckNorris: True User-Agent: Jack Bauer Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 660 Lines: 15 On Thu, Aug 19, 2010 at 10:07:24PM -1000, Zachary Amsden wrote: > When CPUs with unstable TSCs enter deep C-state, TSC may stop > running. This causes us to require resynchronization. Since > we can't tell when this may potentially happen, we assume the > worst by forcing re-compensation for it at every point the VCPU > task is descheduled. > > Signed-off-by: Zachary Amsden Fair enough. -- 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/