From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763739AbZEHXFX (ORCPT ); Fri, 8 May 2009 19:05:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752350AbZEHXFJ (ORCPT ); Fri, 8 May 2009 19:05:09 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33695 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751440AbZEHXFH (ORCPT ); Fri, 8 May 2009 19:05:07 -0400 Date: Fri, 8 May 2009 16:01:42 -0700 From: Andrew Morton To: Ron Cc: mingo@elte.hu, a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fix for sched_clock() when using jiffies Message-Id: <20090508160142.ad89944f.akpm@linux-foundation.org> In-Reply-To: <20090508200444.GA22132@homer.shelbyville.oz> References: <20081126150645.GA28153@homer.shelbyville.oz> <1227712598.4454.199.camel@twins> <20081126153152.GB28153@homer.shelbyville.oz> <20081128144039.GG28138@elte.hu> <20090508132449.GV5417@homer.shelbyville.oz> <20090508200444.GA22132@homer.shelbyville.oz> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 9 May 2009 05:34:44 +0930 Ron wrote: > > Account for the initial offset to the jiffy count. > > Signed-off-by: Ron Lee > > --- > kernel/sched_clock.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c > index a0b0852..a1567b1 100644 > --- a/kernel/sched_clock.c > +++ b/kernel/sched_clock.c > @@ -37,7 +37,8 @@ > */ > unsigned long long __attribute__((weak)) sched_clock(void) > { > - return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); > + return (unsigned long long)(jiffies - INITIAL_JIFFIES) > + * (NSEC_PER_SEC / HZ); > } > > static __read_mostly int sched_clock_running; Why? I assume that you encountered some problem which was fixed by this patch. What was that problem?