Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936551AbcLUP4b (ORCPT ); Wed, 21 Dec 2016 10:56:31 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37784 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936446AbcLUP43 (ORCPT ); Wed, 21 Dec 2016 10:56:29 -0500 Subject: Re: [PATCH v4 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info To: Peter Zijlstra References: <148182699546.5314.279803283347257825.stgit@hbathini.in.ibm.com> <148182702692.5314.556699668213767056.stgit@hbathini.in.ibm.com> <20161215184646.GP3107@twins.programming.kicks-ass.net> <20161216075703.GE3124@twins.programming.kicks-ass.net> <2c0e3bbb-90a1-b5a4-b6d4-19c419ef5411@linux.vnet.ibm.com> <20161216200536.GI3124@twins.programming.kicks-ass.net> <1702a267-0ce6-86da-7755-11a375e450e2@linux.vnet.ibm.com> <20161221132452.GT3124@twins.programming.kicks-ass.net> Cc: ast@fb.com, lkml , acme@kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, daniel@iogearbox.net, rostedt@goodmis.org, Ananth N Mavinakayanahalli , ebiederm@xmission.com, sargun@sargun.me, Aravinda Prasad , brendan.d.gregg@gmail.com From: Hari Bathini Date: Wed, 21 Dec 2016 21:26:12 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20161221132452.GT3124@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16122115-0012-0000-0000-00000385BA33 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16122115-0013-0000-0000-00001AA2C5BF Message-Id: <2af6cd8b-46f3-b60d-581f-30269ea65d53@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-12-21_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1612210249 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1063 Lines: 28 On Wednesday 21 December 2016 06:54 PM, Peter Zijlstra wrote: > On Wed, Dec 21, 2016 at 06:39:01PM +0530, Hari Bathini wrote: >> Hi Peter, >>> I don't see how the tool can parse old records (with NAMESPACES_MAX == >>> 7) if you set its NAMESPACES_MAX to say 10. >>> >>> Then it will expect the link_info array to be 10 entries and either read >>> past the end of the record (if !sample_all) or try and interpret >>> sample_id as link_info records. >>> >> Right. There will be inconsistency with data the perf tool tries to read >> beyond >> what the kernel supports. IIUC, you mean, include nr_namespaces field in the >> record and warn the user if it doesn't match with the one perf-tool supports >> before proceeding..? > Yes, if you add a nr_namespaces field its always parsable. If an old > tool finds more namespace than it has 'names' for it can always display > the raw index number. If a new tool finds the array short, it will not > display the missing ones. > Sure, Peter. Will post the next version as soon as I am back from vacation.. Thanks Hari