From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32310 invoked by alias); 25 Sep 2013 06:04:11 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 32292 invoked by uid 89); 25 Sep 2013 06:04:11 -0000 Received: from e28smtp09.in.ibm.com (HELO e28smtp09.in.ibm.com) (122.248.162.9) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Wed, 25 Sep 2013 06:04:11 +0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.6 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: e28smtp09.in.ibm.com Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 25 Sep 2013 11:34:02 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id AB484394004D for ; Wed, 25 Sep 2013 11:33:45 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r8P63xYP42336356 for ; Wed, 25 Sep 2013 11:33:59 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r8P640EN005546 for ; Wed, 25 Sep 2013 11:34:00 +0530 Received: from localhost.localdomain ([9.124.159.231]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id r8P63xkC005489; Wed, 25 Sep 2013 11:33:59 +0530 Message-ID: <52427CAE.8030600@linux.vnet.ibm.com> Date: Wed, 25 Sep 2013 06:04:00 -0000 From: Hemant User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Masami Hiramatsu CC: Namhyung Kim , linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com, peterz@infradead.org, oleg@redhat.com, mingo@redhat.com, anton@redhat.com, systemtap@sourceware.org Subject: Re: [PATCH 1/2] SDT markers listing by perf References: <20130903072944.4793.93584.stgit@hemant-fedora> <20130903073655.4793.20013.stgit@hemant-fedora> <87ioyht7e4.fsf@sejong.aot.lge.com> <5226E8F4.5060505@hitachi.com> <523599C2.6020204@linux.vnet.ibm.com> <5242687A.9030209@hitachi.com> In-Reply-To: <5242687A.9030209@hitachi.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13092506-2674-0000-0000-00000AC8BEF1 X-SW-Source: 2013-q3/txt/msg00359.txt.bz2 On 09/25/2013 10:07 AM, Masami Hiramatsu wrote: > (2013/09/15 20:28), Hemant wrote: >> Hi Masami, > Hi, and sorry for replying so late. I missed this in my mailbox. > >> On 09/04/2013 01:31 PM, Masami Hiramatsu wrote: >>> (2013/09/04 15:42), Namhyung Kim wrote: >>>> [SNIP] >>>> You need to add it to Documentation/perf-probe.txt too. In addition if >>>> the --sdt option is only able to work with libelf, it should be wrapped >>>> into the #ifdef LIBELF_SUPPORT pair. >>>> >>>> And I'm not sure that it's a good idea to have two behavior on a single >>>> option (S) - show and probe (add). Maybe it can be separated into two >>>> or the S option can be used as a flag with existing --list and --add >>>> option? >>>> >>> Good catch! :) >>> No, that is really bad idea. All probes must be added by "--add" action. >>> So we need a new probe syntax for specifying sdt marker. >>> >>> How about the below syntax? >>> >>> [EVENT=]%PROVIDER:MARKER [ARG ...] >>> >>> Of course, this will require to list up all markers with "%" prefix for >>> continuity. >>> >>> And since --list option is to list up all existing(defined) probe events, >>> I think --markers (as like as --funcs) is better for listing it up. >>> >>> Thank you! >>> >> I have one doubt here. Why do we need [ARG ...] in the syntax you >> specified? I believe these args are to fetched from the sdt notes' >> section of the elf of the executable/library. Or am I taking this in a >> wrong way and this suggested syntax is actually for the uprobe_events >> file in the tracing directory? > Hm, indeed. Since all the arguments of the marker is defined in sdt notes, > we actually don't need to specify each of them. However, other probe syntax > has those arguments. I'd like to keep the same syntax style in the > same command (action) for avoiding confusion. Hmm, got it. > I recommend this way; at the first step, we just find the marker address from > sdt. And next, we will make the argument available. And eventually, > it is better to introduce "$args" meta argument to fetch all the arguments > of the marker. > > At this point, we can do > > perf probe %foo:bar $args So, at first step (ignoring the arguments), we can go with : perf probe %foo:bar And, once, the argument support is enabled (all the arguments will be fetched at the marker location), we can go with: perf probe %foo:bar $args > > to trace full information from the marker foo:bar. > > Thank you, > -- Thanks Hemant Kumar Shaw