From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754758AbYAPN4h (ORCPT ); Wed, 16 Jan 2008 08:56:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752170AbYAPN43 (ORCPT ); Wed, 16 Jan 2008 08:56:29 -0500 Received: from www.tglx.de ([62.245.132.106]:45742 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751379AbYAPN43 (ORCPT ); Wed, 16 Jan 2008 08:56:29 -0500 Date: Wed, 16 Jan 2008 14:54:27 +0100 (CET) From: Thomas Gleixner To: Mike Galbraith cc: LKML , Ingo Molnar , John Stultz , Andrew Morton Subject: Re: [clocksource] jiffies as clocksource kills box In-Reply-To: <1200376168.4137.40.camel@homer.simson.net> Message-ID: References: <1200376168.4137.40.camel@homer.simson.net> User-Agent: Alpine 0.99999 (LFD 796 2007-11-08) 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 On Tue, 15 Jan 2008, Mike Galbraith wrote: > Greetings, > > Per $subject, echo jiffies > current_clocksource pretty thoroughly kills > my P4 box, and does so with every kernel I have (2.6.22->present). I > can drive the box via mouse clicks and poke around, but trying to select > another clocksource thereafter is nogo.. cat current_clocksource emits > jiffies, and box remains comatose unless prodded. I guess your box has high resolution timers and/or dynamic ticks enabled. In that case we really can not switch to jiffies. We also have to prevent PIT from being selected. I have a patch pending for the PIT issue. Will add jiffies to this as well. We'll fix that in .25 as it requires root user interaction and does not show up magically. Thanks, tglx