From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758180Ab0EMPL1 (ORCPT ); Thu, 13 May 2010 11:11:27 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:55920 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751981Ab0EMPL0 (ORCPT ); Thu, 13 May 2010 11:11:26 -0400 X-Authority-Analysis: v=1.1 cv=MoOeBCR3UCSroT7bBzr0mtJUqJhHyBWzyNa37ex1qNU= c=1 sm=0 a=EYIAjt0hOJkA:10 a=hO-oPbc3tlwA:10 a=7U3hwN5JcxgA:10 a=Q9fys5e9bTEA:10 a=gMqfjgEr1zLu/65IO0LwxA==:17 a=Y5_VNCHx5_I71fR9dlIA:9 a=5ZsOWGCs6FV7nlYvsUpO_UfWpRoA:4 a=PUjeQqilurYA:10 a=gMqfjgEr1zLu/65IO0LwxA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.89.75 Subject: Re: [PATCH 3/4] tracing: Allow mmio tracer to display trace_printk() and other events From: Steven Rostedt Reply-To: rostedt@goodmis.org To: Pekka Paalanen Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Frederic Weisbecker , Larry Finger In-Reply-To: <20100513152915.3d3f852b@daedalus.pq.iki.fi> References: <20100513012110.558313399@goodmis.org> <20100513012302.352845720@goodmis.org> <20100513115414.7688b51d@daedalus.pq.iki.fi> <1273752909.27703.809.camel@gandalf.stny.rr.com> <20100513152915.3d3f852b@daedalus.pq.iki.fi> Content-Type: text/plain; charset="ISO-8859-15" Organization: Kihon Technologies Inc. Date: Thu, 13 May 2010 11:11:23 -0400 Message-ID: <1273763483.27703.991.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2010-05-13 at 15:29 +0300, Pekka Paalanen wrote: > On Thu, 13 May 2010 08:15:09 -0400 > > It only displays other events if the user enabled those events. > > > > But that said, I don't want to break existing userspace tools. I > > can add a mmiotrace option "mmiotrace_all_events", if the user > > wants to see all events within the mmiotracer then they can just > > enable that option, otherwise, the mmiotracer will act like it > > currently does. > > > > How does that sound? > > That would be fine. Is it not redundant with what you said in > your first sentence? > Right now with this patch as is. When you enable the mmiotracer it clears the ring buffer. But if someone previously enabled an event (like sched_switch for example) then that event will appear in the output of the tracer. The user will need to disable that event and restart the mmiotracer so the output will not break the userspace tools. Is this OK? If not, then my suggestion is to have an mmiotracer option that keeps it from printing out any event except for the ones it knows about. The reason I added this patch in the first place was because Larry Finger was using the mmiotrace with trace_printk() and the current code does not print out the trace_printk() when mmiotracer is active. -- Steve