From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755181AbYIRMy5 (ORCPT ); Thu, 18 Sep 2008 08:54:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752800AbYIRMyt (ORCPT ); Thu, 18 Sep 2008 08:54:49 -0400 Received: from tac.ki.iif.hu ([193.6.222.43]:58960 "EHLO tac.ki.iif.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752773AbYIRMyt (ORCPT ); Thu, 18 Sep 2008 08:54:49 -0400 X-Greylist: delayed 1715 seconds by postgrey-1.27 at vger.kernel.org; Thu, 18 Sep 2008 08:54:48 EDT From: Ferenc Wagner To: linux-kernel@vger.kernel.org Subject: doubled idle count Date: Thu, 18 Sep 2008 14:26:11 +0200 Message-ID: <87vdwtfxng.fsf@tac.ki.iif.hu> User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, After upgrading a Xen virtual machine to Debian's 2.6.26-4 kernel, I noticed that the idle counter doubled its pace on one of the machines: service2:~# yes >/dev/null & [1] 32578 service2:~# grep cpu0 /proc/stat; sleep 1; grep cpu0 /proc/stat cpu0 141208 9113 57273 13379659 61012 0 792 2350 0 cpu0 141310 9113 57274 13379659 61012 0 792 2350 0 service2:~# fg yes > /dev/null ^C service2:~# grep cpu0 /proc/stat; sleep 1; grep cpu0 /proc/stat cpu0 141952 9113 57277 13383481 61012 0 792 2350 0 cpu0 141953 9113 57278 13383681 61012 0 792 2350 0 One out of three machines show this effect, with the exact same kernel and Xen versions (3.2.0, dom0 is Debian's stock Etch 2.6.18 kernel). They aren't hosted by the same machine, though: the misbehaving one is on a different installation with very similar hardware (3 vs 2 GHz). All the guest are paravirtual. service2:~# cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 3.06GHz stepping : 5 cpu MHz : 3056.482 cache size : 1024 KB physical id : 0 siblings : 1 core id : 0 cpu cores : 1 apicid : 1 initial apicid : 1 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu de tsc msr pae cx8 cmov pat pse36 clflush dts mmx fxsr sse sse2 ss ht pbe up pebs bts cid xtpr bogomips : 6128.11 clflush size : 64 power management: I don't know what else would be useful, please ask. -- Thanks, Feri.