Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932139AbWEGMnS (ORCPT ); Sun, 7 May 2006 08:43:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932140AbWEGMnS (ORCPT ); Sun, 7 May 2006 08:43:18 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:39690 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S932139AbWEGMnS (ORCPT ); Sun, 7 May 2006 08:43:18 -0400 Date: Sun, 7 May 2006 13:43:07 +0100 From: Russell King To: Nick Piggin Cc: Mike Galbraith , Andi Kleen , Christopher Friesen , linux-kernel@vger.kernel.org Subject: Re: sched_clock() uses are broken Message-ID: <20060507124307.GA20443@flint.arm.linux.org.uk> Mail-Followup-To: Nick Piggin , Mike Galbraith , Andi Kleen , Christopher Friesen , linux-kernel@vger.kernel.org References: <20060502132953.GA30146@flint.arm.linux.org.uk> <44578EB9.8050402@nortel.com> <200605021859.18948.ak@suse.de> <445791D3.9060306@yahoo.com.au> <1146640155.7526.27.camel@homer> <445DE925.9010006@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <445DE925.9010006@yahoo.com.au> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1132 Lines: 28 On Sun, May 07, 2006 at 10:33:41PM +1000, Nick Piggin wrote: > Mike Galbraith wrote: > >On Wed, 2006-05-03 at 03:07 +1000, Nick Piggin wrote: > > > >>Other problem is that some people didn't RTFM and have started trying to > >>use it for precise accounting :( > > > > > >Are you talking about me perchance? I don't really care about precision > >_that_ much, though I certainly do want to tighten timeslice accounting. > > No, sched_clock is fine to be used in CPU scheduling choices, which are > heuristic anyway (although strictly speaking, even using it for timeslicing > within a single CPU could cause slight unfairness). Except maybe if it rolls over every 178 seconds, which is my original point. Maybe someone could comment on my initial patch sent 5 days ago? -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - 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/