From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756454Ab0EGPcC (ORCPT ); Fri, 7 May 2010 11:32:02 -0400 Received: from mail.openrapids.net ([64.15.138.104]:56769 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755444Ab0EGPcA (ORCPT ); Fri, 7 May 2010 11:32:00 -0400 Date: Fri, 7 May 2010 11:31:59 -0400 From: Mathieu Desnoyers To: Steven Rostedt Cc: Frederic Weisbecker , linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Arnaldo Carvalho de Melo , Lai Jiangshan , Li Zefan , Masami Hiramatsu , Christoph Hellwig , "H. Peter Anvin" , Andi Kleen , "Paul E. McKenney" Subject: Re: [PATCH 3/9 - v2][RFC] tracing: Remove per event trace registering Message-ID: <20100507153158.GB15267@Krystal> References: <20100504034045.085822814@goodmis.org> <20100504034202.282030521@goodmis.org> <20100507042025.GC8069@nowhere> <20100507145438.GB29573@Krystal> <1273245128.22438.160.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1273245128.22438.160.camel@gandalf.stny.rr.com> X-Editor: vi X-Info: http://www.efficios.com X-Operating-System: Linux/2.6.26-2-686 (i686) X-Uptime: 11:31:39 up 104 days, 18:08, 7 users, load average: 0.15, 0.15, 0.10 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 * Steven Rostedt (rostedt@goodmis.org) wrote: > On Fri, 2010-05-07 at 10:54 -0400, Mathieu Desnoyers wrote: > > * Frederic Weisbecker (fweisbec@gmail.com) wrote: > > > On Mon, May 03, 2010 at 11:40:48PM -0400, Steven Rostedt wrote: > > > > From: Steven Rostedt > > > > > > > > This patch removes the register functions of TRACE_EVENT() to enable > > > > and disable tracepoints. The registering of a event is now down > > > > directly in the trace_events.c file. The tracepoint_probe_register() > > > > is now called directly. > > > > > > > > The prototypes are no longer type checked, but this should not be > > > > an issue since the tracepoints are created automatically by the > > > > macros. If a prototype is incorrect in the TRACE_EVENT() macro, then > > > > other macros will catch it. > > > > > > > > > > > > Agreed. Typechecking matters for human code but not in this context. > > > Considering that the tracepoint and the probe are created by the same > > > CPP code, bugs will be tracked down quickly and located to a single > > > place. > > > > So it seems that I am the only one asking for extra type-checking and > > caring about problems that can appear subtily on architectures where the > > number of caller/callee arguments must match. And also the only one > > considering that passing more arguments to a callback that does not > > expect all of them might be a problem on some architectures. > > > > Am I the only one thinking there is something fishy there ? I might be > > entirely over-paranoid, but this approach has rarely failed me in the > > past. > > I think you are the only one not realizing that the caller and callee > are created automatically with the same data. There is no human > intervention here. > > You are asking to add a check that I can not see helping. The only way > to add a check, is to use the automated process to check the automation. > If the automated process fails, it is very likely the check will also be > broken and will not catch the bug either. Tell me where to fetch the git head, I'll add it myself. ;) Thanks, Mathieu > > -- Steve > > -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com