From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750901AbVHUJeR (ORCPT ); Sun, 21 Aug 2005 05:34:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750902AbVHUJeR (ORCPT ); Sun, 21 Aug 2005 05:34:17 -0400 Received: from smtp.osdl.org ([65.172.181.4]:39387 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1750900AbVHUJeQ (ORCPT ); Sun, 21 Aug 2005 05:34:16 -0400 Date: Sun, 21 Aug 2005 02:32:49 -0700 From: Andrew Morton To: Nick Piggin Cc: tony.luck@intel.com, linux-kernel@vger.kernel.org, jasonuhl@sgi.com Subject: Re: CONFIG_PRINTK_TIME woes Message-Id: <20050821023249.0e143030.akpm@osdl.org> In-Reply-To: <430848F5.3040308@yahoo.com.au> References: <20050821021322.3986dd4a.akpm@osdl.org> <20050821021616.6bbf2a14.akpm@osdl.org> <430848F5.3040308@yahoo.com.au> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nick Piggin wrote: > > Andrew Morton wrote: > > Andrew Morton wrote: > > > >>How about we give each arch a printk_clock()? > > > > > > Which might be as simple as this.. > > > > > > sched_clock() shouldn't really be taken outside kernel/sched.c, > especially for things like this. > > It actually has some fundamental problems even in its current > use in the scheduler (which need to be fixed). But basically it > is a very nasty interface with a rather tenuous relationship to > time. yup. > Why not use something like do_gettimeofday? (or I'm sure one > of our time keepers can suggest the right thing to use). do_gettimeofday() takes locks, so a) we can't do printk from inside it and b) if you do a printk-from-interupt and the interrupted code was running do_gettimeofday(), deadlock.