Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932511AbVJTTcD (ORCPT ); Thu, 20 Oct 2005 15:32:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932502AbVJTTcD (ORCPT ); Thu, 20 Oct 2005 15:32:03 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:30168 "EHLO mx3.mail.elte.hu") by vger.kernel.org with ESMTP id S932511AbVJTTcC (ORCPT ); Thu, 20 Oct 2005 15:32:02 -0400 Date: Thu, 20 Oct 2005 21:32:14 +0200 From: Ingo Molnar To: john stultz Cc: Steven Rostedt , tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: Ktimer / -rt9 (+custom) monotonic_clock going backwards. Message-ID: <20051020193214.GA21613@elte.hu> References: <20051020073416.GA28581@elte.hu> <20051020080107.GA31342@elte.hu> <20051020085955.GB2903@elte.hu> <1129826750.27168.163.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1129826750.27168.163.camel@cog.beaverton.ibm.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.3 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 744 Lines: 21 * john stultz wrote: > > > John, would this cause any problems to keep cycle_t at s64? > > > > I mean at u64. > > Performance would be the only concern. It had been a u64 before I > started optimizing the code a bit. no, this is really a bad optimization that causes unrobustness. Correctness and robustness comes first. It is so easy to cause a 500-1000msec delay in the kernel, due to a bad driver or anything. The timekeeping code should not break like that. 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/