From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 25 Oct 2002 15:47:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 25 Oct 2002 15:47:36 -0400 Received: from 12-237-170-171.client.attbi.com ([12.237.170.171]:12312 "EHLO wf-rch.cirr.com") by vger.kernel.org with ESMTP id ; Fri, 25 Oct 2002 15:47:35 -0400 Message-ID: <3DB9A163.1050306@acm.org> Date: Fri, 25 Oct 2002 14:54:11 -0500 From: Corey Minyard User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0rc3) Gecko/20020523 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Mikael Pettersson CC: linux-kernel@vger.kernel.org Subject: Re: NMI watchdog not ticking at the right intervals References: <200210251802.UAA18166@harpo.it.uu.se> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mikael Pettersson wrote: >On Fri, 25 Oct 2002 09:09:10 -0500, Corey Minyard wrote: > > >>As I have been working on my NMI patch, I have noticed that the NMI >>watchdog does not seem to be ticking correctly. I've tried 2.4 and 2.5 >>kernels, and I get the same results. From my reading of the code, it >>should tick once a second. However, I have had the time between ticks >>vary from around 33 to over 100 seconds. Tbe time between ticks is >>different on every boot, but is consistent once booted. Is there some >>divider register that's not getting initialized? >> >>Here's my cpuinfo: >> >>processor : 0 >>cpu_package : 0 >>vendor_id : GenuineIntel >>cpu family : 6 >>model : 11 >>model name : Intel(R) Pentium(R) III Mobile CPU 1066MHz >> >> > >(Me thinks "speedstep?") > >Do you boot with nmi_watchdog=1 or 2? > It's set to 2 (local APIC). Actually, when I set it to 1 (in 2.5) the code overrides it and sets it to 2. But 2 is what it is running with now. >The perfctr + local-APIC driven NMI watchdog is dependent >on the CPU's clock frequency. If this changes, the NMI rate >will change accordingly. > >The NMI rate may also be affected by APM/ACPI and how often >the kernel executes HLT. > This board is not doing speed stepping. It's running derated for reliability. But that makes me think of something... If I put a program into an infinite loop, then it will step every second like it is supposed to. That makes sense now. Thanks, -Corey