From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751321AbZH1CEx (ORCPT ); Thu, 27 Aug 2009 22:04:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751200AbZH1CEx (ORCPT ); Thu, 27 Aug 2009 22:04:53 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:55866 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751189AbZH1CEw (ORCPT ); Thu, 27 Aug 2009 22:04:52 -0400 Message-ID: <4A973AE9.7020905@cn.fujitsu.com> Date: Fri, 28 Aug 2009 10:03:21 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Ingo Molnar CC: Jens Axboe , Christoph Hellwig , rostedt@goodmis.org, fweisbec@gmail.com, acme@redhat.com, linux-kernel@vger.kernel.org Subject: Re: blktrace ftrace plugin, was Re: Receive side performance issue with multi-10-GigE and NUMA References: <20090826181502.GC13632@elte.hu> <20090826190435.GC10816@hmsreliant.think-freely.org> <20090826190830.GF13632@elte.hu> <20090826.123631.79533250.davem@davemloft.net> <20090826194835.GA16508@elte.hu> <20090826202344.GE10816@hmsreliant.think-freely.org> <20090826204027.GA21159@elte.hu> <20090827003047.GA30341@infradead.org> <20090827052628.GE12579@kernel.dk> <20090827091227.GB4260@elte.hu> In-Reply-To: <20090827091227.GB4260@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-Product-Ver: : ISVW-6.0.0.2339-3.52.0.1010-13974000 X-TM-AS-Result: : No X-TM-AS-Category-Info: : 31:0.000000 X-TM-AS-MatchedID: : 1-90-150567-139010-110609-113228-110581-187067-121108 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Jens Axboe wrote: > >> On Wed, Aug 26 2009, Christoph Hellwig wrote: >>> On Wed, Aug 26, 2009 at 10:40:27PM +0200, Ingo Molnar wrote: >>>> We are also converting non-trivial plugins to generic tracepoints. A >>>> recent example are the system call tracepoints, but we also >>>> converted blktrace and kmemtrace to generic tracepoints. >>> On something semi-related: Any reason to keep the blktrace >>> ftrace plugin around? I don't think there's much point in it. >>> It only got added in 2.6.29, and all the blktrace tooling just >>> uses the legacy ioctls. All new uses should just use the >>> TRACE_EVENT output. >> Lets kill it. > > Agreed. > > I think we should keep the relayfs and ioctl compatibility bits > though: blktrace has a mature user-space environment with many > years of installed base. > > We could even move those bits back to block/blktrace_compat.c or so > (after the ftrace plugin bits are removed), to make sure it's nicely > isolated. > > What do you think? > I'm all for removing the ftrace plugin. There're 2 concerns: - dev_t info can't be recorded in some blk trace events. I think this will change in the future when we can map a request_queue to a unique device? - Not all the output of ftrace plugin comes from tracepoints probing, but via blk_add_trace_msg(), which directly writes a string into ring buffer. I think they need to be converted to TRACE_EVENT.