From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422689AbXBURCk (ORCPT ); Wed, 21 Feb 2007 12:02:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422692AbXBURCk (ORCPT ); Wed, 21 Feb 2007 12:02:40 -0500 Received: from www.osadl.org ([213.239.205.134]:43620 "EHLO mail.tglx.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1422689AbXBURCj (ORCPT ); Wed, 21 Feb 2007 12:02:39 -0500 Subject: Re: Linux 2.6.21-rc1 From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Daniel Walker Cc: Linus Torvalds , Linux Kernel Mailing List , mingo@elte.hu In-Reply-To: <1172075053.8577.38.camel@imap.mvista.com> References: <1172075053.8577.38.camel@imap.mvista.com> Content-Type: text/plain Date: Wed, 21 Feb 2007 18:07:44 +0100 Message-Id: <1172077664.25076.75.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-02-21 at 08:24 -0800, Daniel Walker wrote: > > The most interesting core change may be the dyntick/nohz one, where timer > > ticks will only happen when needed. It's been brewing for a _loong_ time, > > but it's in the standard kernel now as an option. > > On i386 I get the following, > > TCP cubic registered > NET: Registered protocol family 1 > NET: Registered protocol family 17 > Testing NMI watchdog ... CPU#0: NMI appears to be stuck (24->24)! > CPU#1: NMI appears to be stuck (0->0)! > CPU#2: NMI appears to be stuck (0->0)! > CPU#3: NMI appears to be stuck (0->0)! > > when I add nmi_watchdog=1 to my boot args which worked on prior kernels. > On closer inspection it looks like arch/i386/kernel/io_apic.c : > check_timer() --> timer_irq_works() depends on IRQ0 incrementing jiffies > which is no longer the case AFAIK. At this point the PIT / HPET _is_ active and incrementing jiffies. The switch to local apic timers happens afterwards. > I'm not sure exactly how that relates to the NMI, but the check_timer() > function disabled the NMI through the io-apic if it can't get the > "timer" working through the io-apic. Boot log please. tglx