From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-x241.google.com (mail-io0-x241.google.com [IPv6:2607:f8b0:4001:c06::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3w7jhw5tkVzDqB9 for ; Thu, 20 Apr 2017 12:38:08 +1000 (AEST) Received: by mail-io0-x241.google.com with SMTP id x86so10662733ioe.3 for ; Wed, 19 Apr 2017 19:38:08 -0700 (PDT) Subject: Re: [PATCH] of: introduce event tracepoints for dynamic device_node lifecyle To: Tyrel Datwyler , Steven Rostedt References: <1492475525-10827-1-git-send-email-tyreld@linux.vnet.ibm.com> <58F6AA35.2040902@gmail.com> <58F6C088.8020304@gmail.com> <20170418224953.685943a3@grimm.local.home> <641aa8ee-9b54-716a-77a1-076cafb95e3a@linux.vnet.ibm.com> Cc: robh+dt@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, nfont@linux.vnet.ibm.com, mpe@ellerman.id.au, mingo@redhat.com From: Frank Rowand Message-ID: <58F81EF4.5070304@gmail.com> Date: Wed, 19 Apr 2017 19:37:40 -0700 MIME-Version: 1.0 In-Reply-To: <641aa8ee-9b54-716a-77a1-076cafb95e3a@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 04/19/17 11:45, Tyrel Datwyler wrote: > On 04/18/2017 07:49 PM, Steven Rostedt wrote: >> On Tue, 18 Apr 2017 18:42:32 -0700 >> Frank Rowand wrote: >> >>> And of course the other issue with using tracepoints is the extra space >>> required to hold the tracepoint info. With the pr_debug() approach, the >>> space usage can be easily removed for a production kernel via a config >>> option. >> >> Now if you are saying you want to be able to enable debugging without >> the tracing infrastructure I would agree. As the tracing infrastructure >> is large. But I'm working on shrinking it more. > > The primary consumers of OF_DYNAMIC seem to be pseries and powernv where > we are generally going to see the trace infrastructure enabled by > default in production. Another primary consumer will be overlays for ARM expansion boards. Still a work in progress. -Frank > > -Tyrel > >> >>> >>> Tracepoints are wonderful technology, but not always the proper tool to >>> use for debug info. >> >> But if you are going to have tracing enabled regardless, adding a few >> more tracepoints isn't going to make the difference. >> >> -- Steve >> >>> >>>> If Rob wants to convert printk() style data to trace data (and I can't >>>> convince him otherwise) then I will have further comments on this specific >>>> patch. >>>> > > . >