From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754766Ab1K2LHR (ORCPT ); Tue, 29 Nov 2011 06:07:17 -0500 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:38753 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754647Ab1K2LHN (ORCPT ); Tue, 29 Nov 2011 06:07:13 -0500 Message-ID: <4ED4BCD5.3090308@linux.vnet.ibm.com> Date: Tue, 29 Nov 2011 16:37:01 +0530 From: Deepthi Dharwar User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.23) Gecko/20110922 Thunderbird/3.1.15 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel To: Andi Kleen CC: Nicolas Kalkhof , linux-kernel@vger.kernel.org, Linux PM mailing list Subject: Re: Too many poll_idle cpu calls in kernel 3.2 rc-series References: <492649473.3864850.1322512273580.JavaMail.fmail@mwmweb020> <20111128204412.GM24062@one.firstfloor.org> In-Reply-To: <20111128204412.GM24062@one.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 11112911-2674-0000-0000-000001E90536 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/29/2011 02:14 AM, Andi Kleen wrote: > On Mon, Nov 28, 2011 at 09:31:13PM +0100, Nicolas Kalkhof wrote: >> Andi, >> >> correct. The issue was introduced somewhere between 3.1 final and 3.2-rc1. I've tried to track down the bad commit but so far I haven't been successfull. The only workaround I found is to set the idle boot parameter to mwait and to disable CONFIG_INTEL_IDLE. Somehow the kernel seems to set idle to poll by default - no idea why :-(. I wonder if other mobile sandy bridge cpus are affected as well. > > There are only a few changesets affecting drivers/idle > > Can you try to git revert > > 46bcfad7a819bd17ac4e831b04405152d59784ab > 4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 > e978aa7d7d57d04eb5f88a7507c4fb98577def77 > > ? > > -Andi Hi, I am guessing that for workaround just setting the idle boot parameter to mwait should work. Have u tested this without disabling CONFIG_INTEL_IDLE ? Also one thing to note from your logs is, cpu is not entering any of the other C states except for POLL. Can you also check if your are enabling only POLL for idle. I am able to enter deeper C-states on i5-2540M with Intel_Idle enabled. Power top o/p: ------------- Core | CPU 0 CPU 1 POLL 0.0% | POLL 0.0% 0.0 ms 0.0% 0.0 ms C1-SNB 1.4% | C1-SNB 2.2% 0.7 ms 0.5% 0.9 ms C3-SNB 0.9% | C3-SNB 1.6% 1.2 ms 0.1% 1.2 ms C6-SNB 0.2% | C6-SNB 0.3% 1.6 ms 0.0% 0.9 ms C7-SNB 95.8% | C7-SNB 93.7% 3.7 ms 97.8% 15.1 ms Regards, Deepthi