From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751556Ab2DBGvv (ORCPT ); Mon, 2 Apr 2012 02:51:51 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:47662 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751224Ab2DBGvt (ORCPT ); Mon, 2 Apr 2012 02:51:49 -0400 Date: Mon, 2 Apr 2012 08:51:18 +0200 From: Martin Schwidefsky To: Andrew Morton Cc: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, srivatsa.bhat@linux.vnet.ibm.com, mhocko@suse.cz, linux-tip-commits@vger.kernel.org Subject: Re: [tip:timers/core] proc: stats: Use arch_idle_time for idle and iowait times if available Message-ID: <20120402085118.4da62dfe@de.ibm.com> In-Reply-To: <20120330155455.786e8963.akpm@linux-foundation.org> References: <20120330122308.18720283@de.ibm.com> <20120330155455.786e8963.akpm@linux-foundation.org> Organization: IBM Corporation X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit x-cbid: 12040206-0542-0000-0000-0000016EB283 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Mar 2012 15:54:55 -0700 Andrew Morton wrote: > On Fri, 30 Mar 2012 06:58:25 -0700 > tip-bot for Martin Schwidefsky wrote: > > > Commit-ID: cb85a6ed67e979c59a29b7b4e8217e755b951cf4 > > Gitweb: http://git.kernel.org/tip/cb85a6ed67e979c59a29b7b4e8217e755b951cf4 > > Author: Martin Schwidefsky > > AuthorDate: Fri, 30 Mar 2012 12:23:08 +0200 > > Committer: Thomas Gleixner > > CommitDate: Fri, 30 Mar 2012 15:43:33 +0200 > > > > proc: stats: Use arch_idle_time for idle and iowait times if available > > > > Git commit a25cac5198d4ff28 "proc: Consider NO_HZ when printing idle and > > iowait times" changes the code for /proc/stat to use get_cpu_idle_time_us > > and get_cpu_iowait_time_us if the system is running with nohz enabled. > > For architectures which define arch_idle_time (currently s390 only) > > this is a change for the worse. The result of arch_idle_time is supposed > > to be the exact sleep time of the target cpu and should be used instead > > of the value kept by the scheduler. > > So it appears that this patch is a superset of "nohz: fix idle ticks in > cpu summary line of /proc/stat" (below), yes? "proc:stats: Use arch_idle_time.." goes on top of "nohz: fix idle ticks..". If the second patch is applied, s390 does not need the first one anymore. So for s390 the second one is a superset of the first, on x86 the first patch is the important one. > > Signed-off-by: Martin Schwidefsky > > Reviewed-by: Michal Hocko > > Reviewed-by: Srivatsa S. Bhat > > Link: http://lkml.kernel.org/r/20120330122308.18720283@de.ibm.com > > Signed-off-by: Thomas Gleixner > > No cc:stable? Both 09a1d34f8535ecf9 and a25cac5198d date from > September '11 and 09a1d34f8535ecf9 (at least) was a regression. The regression is fixed by "proc:stats: User arch_idle_time..", the second patch gets us back the improved values for s390, you could argue if this is a regression or not. Anyway I would not complain if both patches are included the stable releases. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.