From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757366Ab0KRND2 (ORCPT ); Thu, 18 Nov 2010 08:03:28 -0500 Received: from mail.openrapids.net ([64.15.138.104]:58666 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756980Ab0KRND1 (ORCPT ); Thu, 18 Nov 2010 08:03:27 -0500 Date: Thu, 18 Nov 2010 08:03:24 -0500 From: Mathieu Desnoyers To: Steven Rostedt Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Frederic Weisbecker , Darren Hart , Linus Torvalds , "jason.wessel" , "Ted Ts'o" Subject: Re: [RFC][PATCH 0/2] tracing: Have trace_printk()s in the events/ directory Message-ID: <20101118130324.GB3741@Krystal> References: <20101118035803.453609353@goodmis.org> <1290076866.2109.1305.camel@laptop> <1290081203.30543.96.camel@gandalf.stny.rr.com> <20101118120626.GB27474@Krystal> <1290082454.30543.98.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1290082454.30543.98.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: 08:01:52 up 56 days, 17:04, 1 user, load average: 1.04, 1.22, 1.20 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 Thu, 2010-11-18 at 07:06 -0500, Mathieu Desnoyers wrote: > > * Steven Rostedt (rostedt@goodmis.org) wrote: > > > On Thu, 2010-11-18 at 11:41 +0100, Peter Zijlstra wrote: > > > > On Wed, 2010-11-17 at 22:58 -0500, Steven Rostedt wrote: > > > > > For example, I added a trace_printk() in kernel/sched.c at line 2180 > > > > > and it creates: > > > > > > > > > > # ls /debug/tracing/events/printk/kernel/sched.c/2180/ > > > > > enable format > > > > > > > > > > The format is the printk format: > > > > > > > > > > # cat /debug/tracing/events/printk/kernel/sched.c/2180/format > > > > > "migrate task %s:%d" > > > > > > > > *groan*, so you're creating a tracepoint per instance? > > > > > > > > That's going to be massive pain for perf.. I really don't see the point > > > > in splitting all that out. > > > > > > a) The file directory was what was asked about in the referenced email. > > > b) This is just an example of a way to display it to the user, which > > > seems to be very intuitive. > > > c) Perf can implement the details anyway it wants. It can make a single > > > tracepoint callback and have the enabling of the points as a special > > > filter. > > > d) This was just an RFC that Frederic asked if I would do. I thought it > > > would be a fun challenge and did it. Let it bit rot in hell for all I > > > care, I wasn't taking it any further anyway. > > > > Hi Steven, > > > > The LTTng tree still keeps the "trace_mark()" kernel markers, which are > > very very similar to ftrace_printk(). I'd be happy to combine the two > > eventually. This one file per line approach seems very good -- rather than > > explicitely naming each instance, as I did in trace_mark(), you end up > > automatically naming them by file/line number. > > > > How does this behave from within static inlines called multiple times and > > unrolled loops ? > > Actually you mean macros: > > You'll get a 2181-1, 2181-2, 2181-3, etc. This is neat, great ! :) > > Although a trace_printk() in a header static inline may be interesting. Yep, food for thoughts. ;-) Thank you ! Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com