From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261409AbVGDQoR (ORCPT ); Mon, 4 Jul 2005 12:44:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261415AbVGDQoR (ORCPT ); Mon, 4 Jul 2005 12:44:17 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:3982 "EHLO parcelfarce.linux.theplanet.co.uk") by vger.kernel.org with ESMTP id S261409AbVGDQoG (ORCPT ); Mon, 4 Jul 2005 12:44:06 -0400 Date: Mon, 4 Jul 2005 08:47:03 -0300 From: Marcelo Tosatti To: George Anzinger Cc: Olivier Croquette , Andrew Morton , torvalds@osdl.org, linux-kernel@vger.kernel.org Subject: Re: setitimer expire too early (Kernel 2.4) Message-ID: <20050704114703.GB23082@logos.cnet> References: <42C444AA.2070508@free.fr> <20050630165053.GA8220@logos.cnet> <20050630160537.7d05d467.akpm@osdl.org> <42C582CC.5050907@free.fr> <20050701144901.GC11975@logos.cnet> <42C5B242.5010002@mvista.com> <20050703115659.GA20204@logos.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050703115659.GA20204@logos.cnet> User-Agent: Mutt/1.5.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 03, 2005 at 08:56:59AM -0300, Marcelo Tosatti wrote: > On Fri, Jul 01, 2005 at 02:14:42PM -0700, George Anzinger wrote: > > Marcelo Tosatti wrote: > > >Hi Olivier, > > > > > >On Fri, Jul 01, 2005 at 07:52:12PM +0200, Olivier Croquette wrote: > > > > > >>Andrew Morton wrote: > > >> > > >>>>Linus, Andrew, do you consider this critical enough to be merged to > > >>>>the v2.4 tree? > > >>> > > >>> > > >>>No. I'd expect this would hurt more people than it would benefit. > > >> > > >> > > >>Probably. > > >>Does that mean that the kernel 2.4 will keep this bug for ever? > > > > > > > > >Probably, yes. I've never heard such complaints before your message. > > > > > >The right way to do it seems something else BTW: > > > > > >quoting Nish Aravamudan (http://lkml.org/lkml/2005/4/29/240): > > > > > >Your patch is the only way to guarantee no early timeouts, as far as I > > >know. > > > > > >Really, what you want is: > > > > > >on adding timers, take the ceiling of the interval into which it could be > > >added > > >on expiring timers, take the floor > > > > > >This combination guarantees no timers go off early (and takes away > > >many of these corner cases). I do exactly this in my patch, btw. > > > > IMNSHO that is just another way of saying "add 1 to the jiffie count" which > > is what the proposed patch does. > > Hi George, > > OK - I'll write a test case to confirm there are no such longer delay > regressions as Paulo suggests. > > Thanks for your advice. Hi folks, There is indeed a systematic increase of +20ms when adding "+1" to the expiration interval. Since no one has noticed this before I continue to wonder if its worth adding this to v2.4 at this point in time.