Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754407Ab0FPNYl (ORCPT ); Wed, 16 Jun 2010 09:24:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31782 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750919Ab0FPNYk (ORCPT ); Wed, 16 Jun 2010 09:24:40 -0400 Date: Wed, 16 Jun 2010 10:24:37 -0300 From: Glauber Costa To: Zachary Amsden Cc: avi@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/17] Fix deep C-state TSC desynchronization Message-ID: <20100616132436.GJ19104@mothafucka.localdomain> References: <1276587259-32319-1-git-send-email-zamsden@redhat.com> <1276587259-32319-5-git-send-email-zamsden@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1276587259-32319-5-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: 657 Lines: 14 On Mon, Jun 14, 2010 at 09:34:06PM -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. can't we just compensate everytime check_tsc_unstable() is true? -- 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/