From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756946Ab3ENNsb (ORCPT ); Tue, 14 May 2013 09:48:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2288 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881Ab3ENNsa (ORCPT ); Tue, 14 May 2013 09:48:30 -0400 Message-ID: <5192409C.8040100@redhat.com> Date: Tue, 14 May 2013 09:48:12 -0400 From: Prarit Bhargava User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110419 Red Hat/3.1.10-1.el6_0 Thunderbird/3.1.10 MIME-Version: 1.0 To: Thomas Gleixner CC: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, bitbucket@online.de, tip-bot for Thomas Gleixner , linux-tip-commits@vger.kernel.org Subject: Re: [tip:timers/urgent] tick: Cleanup NOHZ per cpu data on cpu down References: <5190FE00.6010508@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/13/2013 03:10 PM, Thomas Gleixner wrote: > On Mon, 13 May 2013, Prarit Bhargava wrote: >> Thomas, while this does fix up the NULL pointer issue, I think you've introduced >> a new bug in the schedule timer code. > > I don't think that I introduced a new bug. I'm quite sure that change > unearthed another issue which was papered over by the stale data. > > That memset is putting the data structure into the same state as we > have on boot. From tick-sched perspective cpu onlining is not > different between boot and an offline/online cycle > >> While doing up and downs on the same CPU, I now occasionally see long delays in >> the up and down... > >> [ 81.744565] smpboot: Booting Node 1 Processor 19 APIC 0x28 >> [ 82.848591] smpboot: CPU 19 is now offline >> >> Long delay in bringing CPU "up" >> >> [ 89.826533] smpboot: Booting Node 1 Processor 19 APIC 0x28 >> [ 84.905358] smpboot: CPU 19 is now offline >> [ 87.565274] smpboot: Booting Node 1 Processor 19 APIC 0x28 > > Errm, the timestamps are random. -ENOTUSEFUL > I'm always saying my computer is full of lies ;) Here's the bottom line. The patch included in this thread plus the patch you pointed me to here http://marc.info/?l=linux-kernel&m=136847403809031&w=2 seem to resolve the cpu up/down + thermal interrupt issues that I've been seeing. So thank you :) Tested-by: Prarit Bhargava P.