Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751431AbVLFH1E (ORCPT ); Tue, 6 Dec 2005 02:27:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751440AbVLFH1E (ORCPT ); Tue, 6 Dec 2005 02:27:04 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:25247 "EHLO mx3.mail.elte.hu") by vger.kernel.org with ESMTP id S1751431AbVLFH1D (ORCPT ); Tue, 6 Dec 2005 02:27:03 -0500 Date: Tue, 6 Dec 2005 08:27:08 +0100 From: Ingo Molnar To: Ulrich Windl Cc: Roman Zippel , john stultz , lkml , Darren Hart , Nishanth Aravamudan , Frank Sorenson , Thomas Gleixner Subject: Re: [PATCH 2/13] Time: Reduced NTP Rework (part 2) Message-ID: <20051206072708.GA25129@elte.hu> References: <4390E48E.4020005@mvista.com> <4395475C.21877.29399CFE@Ulrich.Windl.rkdvmks1.ngate.uni-regensburg.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4395475C.21877.29399CFE@Ulrich.Windl.rkdvmks1.ngate.uni-regensburg.de> 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=no 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: 1336 Lines: 29 * Ulrich Windl wrote: > > I'm thinking about moving the leap second handling to a timer, with the > > new timer system it would be easy to set a timer for e.g. 23:59.59 and > > then set the time. This way it would be gone from the common path and it > > wouldn't matter that much anymore whether it's used or not. > > Will the timer solution guarantee consistent and exact updates? it would still be dependent on system-load situations. It's an interesting idea to use a timer for that, but there is no strict synchronization between "get time of day" and "timer execution", so any timer-based leap-second handling would be fundamentally asynchronous. I dont think we want that, leap second handling should be a synchronous property of 'time'. i think the very first step should be the cleanups i did to the NTP portions of timer.c. That made all the code (including leap second handling) more readable. I think a portion of the inner desire to rewrite the NTP code comes from the current spaghetti that accumulated over the years. 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/