From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757387Ab1KPPRi (ORCPT ); Wed, 16 Nov 2011 10:17:38 -0500 Received: from he.sipsolutions.net ([78.46.109.217]:33311 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756382Ab1KPPRh (ORCPT ); Wed, 16 Nov 2011 10:17:37 -0500 Subject: Re: [PATCH] tracing: add trace console From: Johannes Berg To: Christoph Hellwig Cc: LKML , Steven Rostedt , Frederic Weisbecker , Ingo Molnar In-Reply-To: <20111116151037.GA26166@infradead.org> References: <1321438728.4773.16.camel@jlt3.sipsolutions.net> <20111116151037.GA26166@infradead.org> Content-Type: text/plain; charset="UTF-8" Date: Wed, 16 Nov 2011 16:17:32 +0100 Message-ID: <1321456652.4502.12.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-11-16 at 10:10 -0500, Christoph Hellwig wrote: > On Wed, Nov 16, 2011 at 11:18:48AM +0100, Johannes Berg wrote: > > From: Johannes Berg > > > > As described in the Kconfig entry, logging printk > > output is useful to correlate (existing) printk > > debugging with (existing) tracing. The easiest way > > to achieve this is to register a console that just > > calls trace_printk(), which this module does. > > I'd much prefer if we could have it built in all the time, but had a > way to enable it at runtime, just like all the "real" tracepoints. That's possible, basically adding a tracepoints to printk -- that would even catch everything and not require setting the console level (which has its advantages too since other consoles might be slow). It's a completely different thing though. I did it this way because it was trivial to do out of tree for a quick test I was doing yesterday. Doing it the other way is obviously more intrusive in core code. johannes