From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758905AbZAMXSb (ORCPT ); Tue, 13 Jan 2009 18:18:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758114AbZAMXRo (ORCPT ); Tue, 13 Jan 2009 18:17:44 -0500 Received: from mx2.redhat.com ([66.187.237.31]:53061 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757884AbZAMXRm (ORCPT ); Tue, 13 Jan 2009 18:17:42 -0500 Date: Tue, 13 Jan 2009 18:16:17 -0500 From: Jason Baron To: Lai Jiangshan Cc: Ingo Molnar , Steven Rostedt , Linux Kernel Mailing List Subject: Re: [PATCH 4/5] ftrace: show ftrace_bprintk()'s formats Message-ID: <20090113231617.GD3210@redhat.com> References: <495ADF57.8030008@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <495ADF57.8030008@cn.fujitsu.com> 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 On Wed, Dec 31, 2008 at 10:56:23AM +0800, Lai Jiangshan wrote: > > Impact: let user knows the format > > Create a file on /tracing/ to show ftrace_bprintk()'s formats. > > This formats will help for these condition: > 1) User get binary data from core file.(formats are backup before coredump) > 2) User splice ring_buffer to a file. > User can use formats for parsing the binary data in userspace. > When I 'cat' trace_bprintk_formats on my system the file is empty. This seems to be b/c 'ftrace_bprintk' is not being used in this patchset. It can't be used in patch #5 during marker register b/c the format wouldn't be known at runtime. Thus, as it currently stands this patch, patch 4/5, isn't adding much? A thought on how this might be resolved would be to have the core marker code pass us its address so this could be recorded in the trace buffer. Then, also add some debug file that displays the markers and maps marker addresses with format strings. thanks, -Jason