Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754952Ab1EKPqI (ORCPT ); Wed, 11 May 2011 11:46:08 -0400 Received: from mail-yi0-f46.google.com ([209.85.218.46]:56006 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754209Ab1EKPqE convert rfc822-to-8bit (ORCPT ); Wed, 11 May 2011 11:46:04 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=vrfy.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=KhV1+N8gH8Az5wRLjCoKEESqy3pJ70olFXR6+zYF3Ryp+2gMSzoeJLMZMw3lw182ae Ps/U+BeaIO2Z95nGPNawdMgj58Mn2JyJT60UxuCv1xqnP6Sc+OaVsGRsx2ySHsj4UAa9 sOrt/MiP0QvhBuRSMZegYlw/VDycvuL5t/lzg= MIME-Version: 1.0 In-Reply-To: <1305121541.2914.213.camel@laptop> References: <1305109433.2914.208.camel@laptop> <1305121541.2914.213.camel@laptop> From: Kay Sievers Date: Wed, 11 May 2011 15:52:14 +0200 Message-ID: Subject: Re: [tip:timers/core] timerfd: Allow timers to be cancelled when clock was set To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, johnstul@us.ibm.com, davidel@xmailserver.org, virtuoso@slind.org, tglx@linutronix.de, chris.friesen@genband.com, kirill@shutemov.name, linux-tip-commits@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1799 Lines: 37 On Wed, May 11, 2011 at 15:45, Peter Zijlstra wrote: > On Wed, 2011-05-11 at 13:58 +0200, Kay Sievers wrote: >> On Wed, May 11, 2011 at 12:23, Peter Zijlstra wrote: >> > On Mon, 2011-05-02 at 19:44 +0000, tip-bot for Thomas Gleixner wrote: >> >> Commit-ID:  99ee5315dac6211e972fa3f23bcc9a0343ff58c4 >> >> Gitweb:     http://git.kernel.org/tip/99ee5315dac6211e972fa3f23bcc9a0343ff58c4 >> >> Author:     Thomas Gleixner >> >> AuthorDate: Wed, 27 Apr 2011 14:16:42 +0200 >> >> Committer:  Thomas Gleixner >> >> CommitDate: Mon, 2 May 2011 21:39:15 +0200 >> >> >> >> timerfd: Allow timers to be cancelled when clock was set >> >> >> >> Some applications must be aware of clock realtime being set >> >> backward. A simple example is a clock applet which arms a timer for >> >> the next minute display. If clock realtime is set backward then the >> >> applet displays a stale time for the amount of time which the clock >> >> was set backwards. Due to that applications poll the time because we >> >> don't have an interface. >> > >> > Shouldn't that clock applet use CLOCK_MONOTONIC for the timer anyway? >> >> Like: Hey let's meet at the bar 5 hours after bootup? :) > > Uhm, the example was a timer to update the displayed time, so a timer > like: wake me next minute, suffices. No, fixed time spans have never been a problem, and are not the example here. It's about the normal wall clock, that wakes up every minute and updates the numbers on the screen. Kay -- 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/