From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758881Ab0EMM3Y (ORCPT ); Thu, 13 May 2010 08:29:24 -0400 Received: from mail-ew0-f216.google.com ([209.85.219.216]:56317 "EHLO mail-ew0-f216.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751866Ab0EMM3W (ORCPT ); Thu, 13 May 2010 08:29:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:in-reply-to:references :x-mailer:mime-version:content-type:content-transfer-encoding; b=eXv42z+hsny3nGTvpGkKWIx5/QI9GDQdJYRHbhNy3yyh0K6cd7bH9N2GZ9B07j3I+a x7dJyJn7mKSzsGpKTqf0Jd9XoUvwlkrews8uPyPpcCOphi+EtwpefFp4fZ/rchv9YONe 1Ir9cGs6TwqOBPIp0DUqqUubtmxQZmZAQy4Nk= Date: Thu, 13 May 2010 15:29:15 +0300 From: Pekka Paalanen To: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Frederic Weisbecker , Larry Finger Subject: Re: [PATCH 3/4] tracing: Allow mmio tracer to display trace_printk() and other events Message-ID: <20100513152915.3d3f852b@daedalus.pq.iki.fi> In-Reply-To: <1273752909.27703.809.camel@gandalf.stny.rr.com> References: <20100513012110.558313399@goodmis.org> <20100513012302.352845720@goodmis.org> <20100513115414.7688b51d@daedalus.pq.iki.fi> <1273752909.27703.809.camel@gandalf.stny.rr.com> X-Mailer: Claws Mail 3.7.5 (GTK+ 2.18.7; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 13 May 2010 08:15:09 -0400 Steven Rostedt wrote: > On Thu, 2010-05-13 at 11:54 +0300, Pekka Paalanen wrote: > > On Wed, 12 May 2010 21:21:13 -0400 > > Steven Rostedt wrote: > > > > > From: Steven Rostedt > > > > > > The mmio tracer has its own function to handle reading of > > > events. But if it encounters an event that it does not > > > understand it ignores it instead of telling the calling > > > function that it is not processing it. > > > > > > If someone adds trace_printk() or enables events along with > > > the mmio tracer, then these events will not be displayed in > > > the trace output. > > > > > > Simple solution is to just have the mmio print return > > > UNHANDLED to let the caller know that it did not processes > > > the event and the caller can process the event further. > > > > Does this not mean that the mmiotrace output may contain > > foreign lines? If it does, it will break the user space. > > The dump format is specified in > > Documentation/trace/mmiotrace.txt. > > > > If you want to handle arbitrary messages, format them as > > MARK events, please. > > > > If I understood correctly, then NAK for this patch. Otherwise, > > could you explain how this does not break the mmiotrace dump > > format? > > > > Is the tracing infrastructure now supporting several > > active tracers at the same time? If yes, and if mmiotrace > > should be able to co-operate, we need a new revision of the > > dump format, or a tool that extracts the mmiotrace > > events in the current format. > > > > 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? -- Pekka Paalanen http://www.iki.fi/pq/