Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753077AbXLHTRd (ORCPT ); Sat, 8 Dec 2007 14:17:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751659AbXLHTR0 (ORCPT ); Sat, 8 Dec 2007 14:17:26 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:34531 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751609AbXLHTRZ (ORCPT ); Sat, 8 Dec 2007 14:17:25 -0500 Date: Sat, 8 Dec 2007 20:16:29 +0100 From: Ingo Molnar To: Arjan van de Ven Cc: Guillaume Chazarain , Thomas Gleixner , Stefano Brivio , Robert Love , linux-kernel@vger.kernel.org, Dave Jones , "Rafael J. Wysocki" , Michael Buesch , Andrew Morton Subject: Re: [patch] x86: scale cyc_2_nsec according to CPU frequency Message-ID: <20071208191629.GB21186@elte.hu> References: <20071207021952.6f0ac922@morte> <3d8471ca0712062318j483f8be6h256778752a13639a@mail.gmail.com> <20071207090252.1caf1509@inria.fr> <20071207135525.GA5588@elte.hu> <20071207152741.3408aeef@inria.fr> <20071207145206.GA21326@elte.hu> <20071208075735.4700bcac@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071208075735.4700bcac@laptopd505.fenrus.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1050 Lines: 26 * Arjan van de Ven wrote: > > > > Firstly, we dont need the 'offset' anymore because cpu_clock() > > > > maintains offsets itself. > > > > > > Yes, but a lower quality one. __update_rq_clock tries to > > > compensate large jumping clocks with a jiffy resolution, while my > > > offset arranges for a very smooth frequency transition. > > > > yes, but that would be easy to fix up via calling > > sched_clock_idle_wakeup_event(0) when doing a frequency transition, > > without burdening the normal sched_clock() codepath with the offset. > > See the attached latest version. > > can this deal with dual/quad core where the frequency of one core > changes if the sofware changes the frequency of the other core? doesnt the notifier still get run on the target CPU? Ingo -- 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/