From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754868Ab1K1UQf (ORCPT ); Mon, 28 Nov 2011 15:16:35 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:60685 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754386Ab1K1UQe (ORCPT ); Mon, 28 Nov 2011 15:16:34 -0500 From: "Rafael J. Wysocki" To: Tino Keitel , Michal Hocko Subject: Re: [REGRESSION] [Linux 3.2] top/htop and all other CPU usage metering applications has gone crackers Date: Mon, 28 Nov 2011 21:19:26 +0100 User-Agent: KMail/1.13.6 (Linux/3.2.0-rc3+; KDE/4.6.0; x86_64; ; ) Cc: linux-kernel@vger.kernel.org, "Artem S. Tashkinov" References: <1718181782.740375.1322130615898.JavaMail.mail@webmail19> <201111271245.57772.rjw@sisk.pl> <20111128195533.GA26460@mac.home> In-Reply-To: <20111128195533.GA26460@mac.home> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111282119.26474.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, November 28, 2011, Tino Keitel wrote: > On Sun, Nov 27, 2011 at 12:45:57 +0100, Rafael J. Wysocki wrote: > > On Sunday, November 27, 2011, Tino Keitel wrote: > > > On Thu, Nov 24, 2011 at 21:05:53 +0100, Tino Keitel wrote: > > > > On Thu, Nov 24, 2011 at 10:30:15 +0000, Artem S. Tashkinov wrote: > > > > > Hello, > > > > > > > > > > I'd like to report a weird regression in Linux 3.2 (running rc3 now) - all CPU metering applications have gone terribly mad > > > > > under this kernel: > > > > > > > > I get the same using top, htop and the gnome system monitor with kernel > > > > 3.2 on a Sandy Bridge quad core box, running Debian unstable. > > > > > > I just tested 3.2-rc2, and see the same bug. > > > > I'm seeing that too on one of my test boxes, but not all the time > > (i.e. there are periods in which the readings are correct). The other boxes > > I've tested with 3.2-rc are fine in that respect. > > > > Also, it seems that it shows 100%-(real load) when it is wrong. So, it looks > > like there's an overflow somewhere in the CPU load measuring code, at least > > on some CPUs. > > Hi, > > I reverted this commit and so far it looks good: > > commit a25cac5198d4ff2842ccca63b423962848ad24b2 > Author: Michal Hocko > Date: Wed Aug 24 09:40:25 2011 +0200 > > proc: Consider NO_HZ when printing idle and iowait times > > I'll report back tomorrow how the kernel behaves. Hmm. Michal, can you have a look at that, please? Rafael