From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938652AbXGSOsE (ORCPT ); Thu, 19 Jul 2007 10:48:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765301AbXGSOrS (ORCPT ); Thu, 19 Jul 2007 10:47:18 -0400 Received: from gw.goop.org ([64.81.55.164]:50026 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757701AbXGSOrR (ORCPT ); Thu, 19 Jul 2007 10:47:17 -0400 Message-ID: <469F793E.6030006@goop.org> Date: Thu, 19 Jul 2007 07:46:22 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.4 (X11/20070615) MIME-Version: 1.0 To: Ingo Molnar CC: Andrew Morton , linux-kernel@vger.kernel.org, Linus Torvalds , stable@kernel.org, Greg KH , Chris Wright Subject: Re: [patch] fix the softlockup watchdog to actually work References: <20070717114453.GA8212@elte.hu> <469CCF8F.4010107@goop.org> <20070717154934.GA24231@elte.hu> <20070719002231.069ebbdd.akpm@linux-foundation.org> <20070719075152.GB12760@elte.hu> <469F75AF.5080000@goop.org> <20070719143528.GA8278@elte.hu> In-Reply-To: <20070719143528.GA8278@elte.hu> X-Enigmail-Version: 0.95.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > sched_clock(), as its name suggests it, is meant for the scheduler's > use. The scheduler generally only needs to measure time when the CPU is > busy - not across idle periods. So sched_clock() can (and will) break > across certain types of ACPI idle methods. > Hm, or more specifically, why would that be a problem for softlockup? Do you mean it doesn't measure time during ACPI idle? That would just make it trigger later than it would otherwise. Andrew is reporting that it is triggering very early, and making the machine feel jerky. How can that be related to sched_clock's quality, unless its too broken to be useful to anyone for anything? J