From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161358AbaDPNwH (ORCPT ); Wed, 16 Apr 2014 09:52:07 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:36941 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161259AbaDPNwE (ORCPT ); Wed, 16 Apr 2014 09:52:04 -0400 Date: Wed, 16 Apr 2014 14:45:06 +0100 From: Will Deacon To: AKASHI Takahiro Cc: "rostedt@goodmis.org" , "fweisbec@gmail.com" , "mingo@redhat.com" , Catalin Marinas , "tim.bird@sonymobile.com" , "gkulkarni@caviumnetworks.com" , "dsaxena@linaro.org" , "arndb@arndb.de" , "linux-arm-kernel@lists.infradead.org" , "linaro-kernel@lists.linaro.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v7 4/7] arm64: Add ftrace support Message-ID: <20140416134506.GD1001@arm.com> References: <1394705630-12384-1-git-send-email-takahiro.akashi@linaro.org> <1394862353-28963-5-git-send-email-takahiro.akashi@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1394862353-28963-5-git-send-email-takahiro.akashi@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 15, 2014 at 05:45:50AM +0000, AKASHI Takahiro wrote: > This patch implements arm64 specific part to support function tracers, > such as function (CONFIG_FUNCTION_TRACER), function_graph > (CONFIG_FUNCTION_GRAPH_TRACER) and function profiler > (CONFIG_FUNCTION_PROFILER). > > With 'function' tracer, all the functions in the kernel are traced with > timestamps in ${sysfs}/tracing/trace. If function_graph tracer is > specified, call graph is generated. > > The kernel must be compiled with -pg option so that _mcount() is inserted > at the beginning of functions. This function is called on every function's > entry as long as tracing is enabled. > In addition, function_graph tracer also needs to be able to probe function's > exit. ftrace_graph_caller() & return_to_handler do this by faking link > register's value to intercept function's return path. > > More details on architecture specific requirements are described in > Documentation/trace/ftrace-design.txt. > > Reviewed-by: Ganapatrao Kulkarni > Signed-off-by: AKASHI Takahiro I'm still slightly suspicious about the alignment of your ASCII art, but: Acked-by: Will Deacon Will