Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753840AbcC1EzM (ORCPT ); Mon, 28 Mar 2016 00:55:12 -0400 Received: from mail-qk0-f177.google.com ([209.85.220.177]:35600 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753631AbcC1EzH (ORCPT ); Mon, 28 Mar 2016 00:55:07 -0400 MIME-Version: 1.0 In-Reply-To: <56F54628.4000404@fb.com> References: <05d6338bddae751c1755e7825d4179658e78cc71.1458819912.git.baolin.wang@linaro.org> <56F3F4F5.8050200@fb.com> <56F54628.4000404@fb.com> Date: Mon, 28 Mar 2016 12:55:05 +0800 Message-ID: Subject: Re: [PATCH] mmc: Provide tracepoints for request processing From: Baolin Wang To: Jens Axboe Cc: Ulf Hansson , Steven Rostedt , mingo@redhat.com, adrian.hunter@intel.com, yangbo.lu@freescale.com, akpm@linux-foundation.org, JBottomley@odin.com, lporzio@micron.com, jonathanh@nvidia.com, Grant Grundler , fabf@skynet.be, yunpeng.gao@intel.com, dan.j.williams@intel.com, rabin.vincent@axis.com, chuanxiao.dong@intel.com, shawn.lin@rock-chips.com, =?UTF-8?Q?Heiko_St=C3=BCbner?= , Douglas Anderson , david@protonic.nl, Mark Brown , Linus Walleij , Takahiro Akashi , LKML , linux-mmc@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1345 Lines: 44 On 25 March 2016 at 22:07, Jens Axboe wrote: > On 03/25/2016 01:32 AM, Baolin Wang wrote: >> >> On 24 March 2016 at 22:08, Jens Axboe wrote: >>> >>> On 03/24/2016 05:54 AM, Baolin Wang wrote: >>>> >>>> >>>> This patch provides some tracepoints for the lifecycle of a request from >>>> fetching to completion to help with performance analysis of MMC >>>> subsystem. >>> >>> >>> >>> Most of these already exist as block layer trace points, why do we need >>> mmc >>> specific ones? >> >> >> Currently the MMC core does not have any tracepoints for use with >> ftrace. These are very useful as they provide a very low overhead >> runtime controllable way of getting diagnostics from the system which >> is capable of recording a great deal of information without impacting >> system performance. We have tracepoints in the block layer so we can >> do some trace of MMC but none in MMC itself so adding some where >> appropriate would help people follow the activity of subsystem. > > > But more than half of the trace points you added, those are DIRECTLY related > to the block event. So what you are saying makes little sense. I see you > resend it with the same trace points, I'll comment on that mail. OK. I'll address your comments on that new mail. Thanks. > > -- > Jens Axboe > -- Baolin.wang Best Regards