Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756045Ab0KJNrI (ORCPT ); Wed, 10 Nov 2010 08:47:08 -0500 Received: from one.firstfloor.org ([213.235.205.2]:36464 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755816Ab0KJNrF (ORCPT ); Wed, 10 Nov 2010 08:47:05 -0500 Date: Wed, 10 Nov 2010 14:47:01 +0100 From: Andi Kleen To: john stultz Cc: Andi Kleen , LKML , Thomas Gleixner , Ingo Molnar , Martin Schwidefsky , Clark Williams Subject: Re: [PATCH] Greatly improve TSC calibration using a delayed workqueue Message-ID: <20101110134700.GB7205@basil.fritz.box> References: <1289003985-29060-1-git-send-email-johnstul@us.ibm.com> <20101107204153.GA17592@basil.fritz.box> <1289253887.2798.40.camel@localhost.localdomain> <20101109134355.GA29433@basil.fritz.box> <1289338900.9434.51.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1289338900.9434.51.camel@localhost.localdomain> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1159 Lines: 26 On Tue, Nov 09, 2010 at 01:41:40PM -0800, john stultz wrote: > > It may happen with opportunistic suspend if the system boots very fast. > > Right, but a system using opportunistic suspend will have a hard enough > time keeping close NTP sync on its own given the frequent switching > between the fine-grained ntp adjusted clocksource during run-time and > the coarse non-adjusted RTC/persisitent_clock while suspended. > > So I think such a system would be fine it falls back to using just the > boot-calibration for TSC freq rather then the refined calibration freq > calculated by this patch (which will happen automatically if the refined > calibration is off by 1%). > > Does that seem like a reasonable tradeoff? Yes it sounds good to me. Some inaccuracy in this case is fine I guess. Just major inaccuracy or a crash or hang wouldn't be good. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/