From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754958Ab1K1UCD (ORCPT ); Mon, 28 Nov 2011 15:02:03 -0500 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:35512 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754779Ab1K1UB6 (ORCPT ); Mon, 28 Nov 2011 15:01:58 -0500 Message-ID: <4ED3E8AD.6050304@linux.vnet.ibm.com> Date: Tue, 29 Nov 2011 01:31:49 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux i686; rv:7.0) Gecko/20110927 Thunderbird/7.0 MIME-Version: 1.0 To: Nicolas Kalkhof CC: linux-kernel@vger.kernel.org, Linux PM mailing list , Deepthi Dharwar Subject: Re: Too many poll_idle cpu calls in kernel 3.2 rc-series References: <1587582695.5658131.1322424808507.JavaMail.fmail@mwmweb005> In-Reply-To: <1587582695.5658131.1322424808507.JavaMail.fmail@mwmweb005> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit x-cbid: 11112820-9574-0000-0000-00000053817D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adding linux-pm mailing list to CC. Thanks, Srivatsa S. Bhat On 11/28/2011 01:43 AM, Nicolas Kalkhof wrote: > the kernel v3.2 series shows excessive poll_idle calls during system idle phases causing the cpu > (mobile i7 2620M) to heat up and draw additional 10% more power. All kernel versions between > 3.2-rc1 and 3.2-rc3 are affected. Perf Top and Powertop both show the same issue. > I've posted a similar bug report before: http://marc.info/?l=linux-kernel&m=132164909313594&w=2 > and used perf top -U to verify the poll_idle calls as requested. > > dmesg and kernel .config attached. > > Could someone please confirm this issue? > > Thanks and Regards > Nic > > perf top -U shows: > Events: 30K cycles > 97.88% [kernel] [k] poll_idle > 0.17% [kernel] [k] sdhci_irq > 0.08% [kernel] [k] unix_poll > 0.06% [kernel] [k] _raw_spin_lock_irqsave > 0.06% [kernel] [k] page_fault > 0.05% [kernel] [k] fget_light > 0.05% [kernel] [k] format_decode > 0.04% [kernel] [k] kmem_cache_alloc > 0.04% [kernel] [k] clear_page > 0.04% [kernel] [k] _raw_spin_unlock_irqrestore > 0.03% [kernel] [k] do_select > 0.03% [kernel] [k] seq_printf > 0.03% [kernel] [k] vfs_read > 0.03% [kernel] [k] _raw_spin_lock > 0.03% [kernel] [k] vsnprintf > 0.03% [kernel] [k] number.clone.1 > 0.03% [kernel] [k] fput > > Powertop shows: > n Avg residency P-states (frequencies) > C0 (cpu running) ( 5.4%) Turbo Mode 1.5% > polling 1.8ms (94.6%) 2.71 Ghz 0.1% > C1 mwait 0.0ms ( 0.0%) 2.21 Ghz 0.1% > C2 mwait 0.0ms ( 0.0%) 1400 Mhz 0.1% > C3 mwait 0.0ms ( 0.0%) 800 Mhz 98.2% > C4 mwait 0.0ms ( 0.0%) > Wakeups-from-idle per second : 529.4 interval: 5.0s >