From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759352AbYEMTEV (ORCPT ); Tue, 13 May 2008 15:04:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754828AbYEMTEK (ORCPT ); Tue, 13 May 2008 15:04:10 -0400 Received: from rv-out-0506.google.com ([209.85.198.237]:27528 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887AbYEMTEI (ORCPT ); Tue, 13 May 2008 15:04:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=YUJyJP7WfgVeXKac0YLlqFDBj3cEDjtJzA3ryXQpbeQC0Xgw1AqhcK7Z/SimDAGN0CPMpK56CYux3VgjO8OF7QhOMKjGJ7CTMe57I4Lp6vtGkovO9hvYNzctbTSQDUTbLTbNI/cGOfWOs2ShXuIZQHd6V+UhzzZMCj8LoxnN0yA= Message-ID: <19f34abd0805131204y5a3f32c0ya137c0f6e4bfa386@mail.gmail.com> Date: Tue, 13 May 2008 21:04:05 +0200 From: "Vegard Nossum" To: "Ingo Molnar" Subject: Re: Rescheduling interrupts Cc: "=?UTF-8?Q?S.=C3=87a=C4=9Flar_Onur?=" , LKML , "Arjan van de Ven" In-Reply-To: <19f34abd0805131103q136e28ddg359de5822b401e0c@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline References: <200801220119.42312.caglar@pardus.org.tr> <200801221455.16814.caglar@pardus.org.tr> <20080122152333.GB19590@elte.hu> <200801221755.56470.caglar@pardus.org.tr> <20080122160557.GA31831@elte.hu> <19f34abd0805131103q136e28ddg359de5822b401e0c@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by alpha.home.local id m4DJ4bEB023641 On Tue, May 13, 2008 at 8:03 PM, Vegard Nossum wrote:> Hi,>>> On Tue, Jan 22, 2008 at 6:05 PM, Ingo Molnar wrote:> >> > * S.Çağlar Onur wrote:> >> >> > > > My theory is that for whatever reason we get "repeat" IPIs: multiple> > > > reschedule IPIs although the other CPU only initiated one.> > >> > > Ok, please see http://cekirdek.pardus.org.tr/~caglar/dmesg.3rd :)> >> > hm, the IPI sending and receiving is nicely paired up:> >> > [ 625.795008] IPI (@smp_reschedule_interrupt) from task swapper:0 on CPU#1:> > [ 625.795223] IPI (@native_smp_send_reschedule) from task amarokapp:2882 on CPU#1:> >> > amarokapp does wake up threads every 20 microseconds - that could> > explain it. It's probably Xorg running on one core, amarokapp on the> > other core. That's already 100 reschedules/sec.>> Was this IPI thing ever resolved/fixed? I'm seeing the exact same> thing on my newest Fedora 8 kernel (2.6.24.5-85.fc8) now:>> 33.3% (334.0) : Rescheduling interrupts>> And I know for sure that this did not show up a couple of months back.>> If the cause of this is known, please let me know about it. If it> isn't, I will start a bisect run now :-) Ok -- just a confirmation. I have this on v2.6.26-rc1: Running only init=/bin/sh (from busybox) and powertop shows:kernel IPI : Rescheduling interrupts completely idle box (except powertop): 1 wakeups/secone busy-loop[1]: 2 wakeups/sectwo busy-loops: 500 wakeups/sec So it seems like a real bug to me. Vegard [1]: while true; do echo hi; done -- "The animistic metaphor of the bug that maliciously sneaked in whilethe programmer was not looking is intellectually dishonest as itdisguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036{.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I