From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754708AbYIRPwM (ORCPT ); Thu, 18 Sep 2008 11:52:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756061AbYIRPvz (ORCPT ); Thu, 18 Sep 2008 11:51:55 -0400 Received: from mx1.redhat.com ([66.187.233.31]:34693 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756113AbYIRPvy (ORCPT ); Thu, 18 Sep 2008 11:51:54 -0400 Date: Thu, 18 Sep 2008 11:50:41 -0400 From: Jason Baron To: "H. Peter Anvin" Cc: Ingo Molnar , Andrew Morton , Yinghai Lu , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/6] loglevel=pci:8,acpi:8,apic=8 support v6 Message-ID: <20080918155041.GB3097@redhat.com> References: <1221640067-24389-1-git-send-email-yhlu.kernel@gmail.com> <20080917015543.27172da4.akpm@linux-foundation.org> <20080917092732.GB32107@elte.hu> <20080917184618.GB6486@redhat.com> <48D159A7.5080907@zytor.com> <20080918105728.GF20967@elte.hu> <48D2758B.1000004@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48D2758B.1000004@zytor.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 18, 2008 at 08:36:43AM -0700, H. Peter Anvin wrote: > Ingo Molnar wrote: >> >> which is what we really want. If a bootup fails, the user has to repeat >> the bootup at least once with a verbosity level increased and with >> (hopefully) some sort of log capture facility attached. >> >> So the point would be, if the user specified loglevel=all, we would get >> really comprehensive, one-stop-shop output. >> > > That is true if the bootup fails, but it's fairly common that we get the > machine up (at least to the point when we can dmesg), but the user wants > to report a problem. For that case, it's very nice if the dmesg log > contains as much information as possible. > > So I don't think it's clear that pre-filtering is what we want, at all. > > -hpa > hi, if we take this argument to its extreme, then we end up spending all of our time verifying that the kernel is working correctly and no time actually doing work. I think 'printk_ratelimit' captures this. Thus, the line has to be drawn somewhere. If you want the messages in 'dmesg' use, printk(KERN_DEBUG), and 'grep'. For the rest, I propose pre-filtering, which is what 'dynamic debug' uses. thanks, -Jason