From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756491Ab1GEM5Z (ORCPT ); Tue, 5 Jul 2011 08:57:25 -0400 Received: from hera.kernel.org ([140.211.167.34]:59539 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756321Ab1GEM5W (ORCPT ); Tue, 5 Jul 2011 08:57:22 -0400 Date: Tue, 5 Jul 2011 12:56:31 GMT From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, torvalds@linux-foundation.org, ncrao@google.com, a.p.zijlstra@chello.nl, efault@gmx.de, alex.shi@intel.com, akpm@linux-foundation.org, tglx@linutronix.de, tom.leiming@gmail.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, ncrao@google.com, torvalds@linux-foundation.org, efault@gmx.de, alex.shi@intel.com, akpm@linux-foundation.org, tglx@linutronix.de, tom.leiming@gmail.com, mingo@elte.hu To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched: Disable (revert) SCHED_LOAD_SCALE increase Git-Commit-ID: e4c2fb0d5776b58049d2556b456144a4db3fe5a9 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 05 Jul 2011 12:56:32 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e4c2fb0d5776b58049d2556b456144a4db3fe5a9 Gitweb: http://git.kernel.org/tip/e4c2fb0d5776b58049d2556b456144a4db3fe5a9 Author: Peter Zijlstra AuthorDate: Tue, 5 Jul 2011 10:56:32 +0200 Committer: Ingo Molnar CommitDate: Tue, 5 Jul 2011 11:28:18 +0200 sched: Disable (revert) SCHED_LOAD_SCALE increase Alex reported that commit c8b281161df ("sched: Increase SCHED_LOAD_SCALE resolution") caused a power usage regression under light load as it increases the number of load-balance operations and keeps idle cpus from staying idle. Time has run out to find the root cause for this release so disable the feature for v3.0 until we can figure out what causes the problem. Reported-by: "Alex, Shi" Signed-off-by: Peter Zijlstra Cc: Nikhil Rao Cc: Ming Lei Cc: Mike Galbraith Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/n/tip-m4onxn0sxnyn5iz9o88eskc3@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index a837b20..496770a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -808,7 +808,7 @@ enum cpu_idle_type { * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the * increased costs. */ -#if BITS_PER_LONG > 32 +#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load */ # define SCHED_LOAD_RESOLUTION 10 # define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION) # define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION)