From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 9769CA051A; Fri, 17 Jan 2020 12:08:29 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 04430F72; Fri, 17 Jan 2020 12:08:28 +0100 (CET) Received: from mail-il1-f193.google.com (mail-il1-f193.google.com [209.85.166.193]) by dpdk.org (Postfix) with ESMTP id B0D96F11; Fri, 17 Jan 2020 12:08:26 +0100 (CET) Received: by mail-il1-f193.google.com with SMTP id g12so20976565ild.2; Fri, 17 Jan 2020 03:08:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wKvuIc3DHJbfzP+NnGpqXH7ch+oN3lGyKxh+t/+xsv0=; b=FDowQ53i0U8Cgo6zo8Ji7e6IYODG/AmtH+re6UYjI764tyMufQhfuDu0smENr8dkN+ 6rYD+q4rfnu8J3erE70w71+5cAh2jw10wVAXXUVuZWwSDQvWkV+TsS5U8K/SWE9Z4XmJ YR0ygGcQpNU0v3x4TP9kfshPwmH4QqK97Uncs26vFXqkOPedfQqLkYKJ+/oSqLI3s4WL FhF8VJ/NTnSg3I4ikW1RFDlZbpt+Ldbkxw0n1HGyDbgKakLxfpAt5hkDFKkJPw92j4is V7YnnHRye2MFcEYJZcAcrdhwAtf3WsOb9EyXYiKYZS2oAKm8eAN9pK/WgmN2pQjDJSC+ CFnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wKvuIc3DHJbfzP+NnGpqXH7ch+oN3lGyKxh+t/+xsv0=; b=YmBGp9RyeUIVJnEN7PxzgeRuv2yu0XapWuJ/hpXRpeWHU7zSdkZDSVEp/0rmcH+iGA BbHIFnOH5ozgeCHznubIGx0n/rR621xgCQcn4zTDJ+vuWUbdfD8wBJavHPkcTdDVrRSZ 1IfhxUo927JstacdX88kAO4zikhuWce24p0eGxZiVCFLGHVr+tSlS2YhMJlj0M8cyCRJ BehiHBNPKYLaPccjGI8jOhIZe98IZRh4Mr4I5NMaLF6n/lMaAGThM46YmMocSLzgykUx TmbzRTBjCeeAJ7JD8I5CHRU1zPnIRm+0m+TSovsjBsDoIwXRBIseClv0N9l/grieMS40 vsVQ== X-Gm-Message-State: APjAAAXrS4MOK8XHv8/YOqYuMtmtX/Uw9EPJPeeWpsoM5qXxjrSpO8R9 JyPTXwU7+j6YbGVIWCVIKBddP0/B+yiiT8duEhE= X-Google-Smtp-Source: APXvYqwaTHkvCbHDLV9fTlIm7PHI600hFb5nqJu/RY9s7ec0JCcG3NFOzCq6aKjQ3ZSmysAXkHzTwFtwNblX62AOPcU= X-Received: by 2002:a92:481d:: with SMTP id v29mr2456124ila.271.1579259305831; Fri, 17 Jan 2020 03:08:25 -0800 (PST) MIME-Version: 1.0 References: <20200113130543.GC1645@bricha3-MOBL.ger.corp.intel.com> <20200113145823.GD1645@bricha3-MOBL.ger.corp.intel.com> <20200113161259.GE1645@bricha3-MOBL.ger.corp.intel.com> In-Reply-To: From: Jerin Jacob Date: Fri, 17 Jan 2020 16:38:09 +0530 Message-ID: To: David Marchand Cc: Bruce Richardson , Jerin Jacob Kollanukkaran , "dev@dpdk.org" , Thomas Monjalon , Ferruh Yigit , Andrew Rybchenko , Ajit Khaparde , Qi Zhang , Xiaolong Ye , Raslan Darawsheh , Maxime Coquelin , Tiwei Bie , Akhil Goyal , Luca Boccassi , Kevin Traynor , "maintainers@dpdk.org" , John McNamara , Marko Kovacevic , Ray Kinsella , Aaron Conole , Michael Santana , Harry van Haaren , Cristian Dumitrescu , Phil Yang , Joyce Kong , =?UTF-8?Q?Mattias_R=C3=B6nnblom?= , Jan Viktorin , Gavin Hu , David Christensen , Konstantin Ananyev , Anatoly Burakov , Harini Ramakrishnan , Omar Cardona , Anand Rawat , Olivier Matz , Gage Eads , Adrien Mazarguil , Nicolas Chautru , Declan Doherty , Fiona Trahe , Ashish Gupta , Erik Gabriel Carrillo , Abhinandan Gujjar , Hemant Agrawal , "Artem V. Andreev" , Nithin Kumar Dabilpuram , Vamsi Krishna Attunuru , Rosen Xu , Sachin Saxena , Stephen Hemminger , Chas Williams , "John W. Linville" , Prasun Kapoor , Marcin Wojtas , Michal Krawczyk , Guy Tzalik , Evgeny Schemeilin , Igor Chauskin , Ravi Kumar , Igor Russkikh , Pavel Belous , Shepard Siegel , Ed Czeck , John Miller , Somnath Kotur , Maciej Czekaj , Shijith Thotton , Srisivasubramanian Srinivasan , Rahul Lakkireddy , John Daley , Hyong Youb Kim , "Wei Hu (Xavier" , "Min Hu (Connor" , Yisen Zhuang , Ziyang Xuan , Xiaoyun Wang , Guoyang Zhou , Beilei Xing , Xiao Wang , Jingjing Wu , Wenzhuo Lu , Qiming Yang , Tomasz Duszynski , Liron Himi , Zyta Szpak , Kiran Kumar Kokkilagadda , Matan Azrad , Shahaf Shuler , Viacheslav Ovsiienko , "K. Y. Srinivasan" , Haiyang Zhang , Jan Remes , Heinrich Kuhn , Jan Gutter , Gagandeep Singh , Rasesh Mody , Shahed Shaikh , Yong Wang , Zhihong Wang , Steven Webster , Matt Peters , Keith Wiles , Tetsuya Mukawa , Jasvinder Singh , Jakub Grajciar , Ruifeng Wang , Anoob Joseph , Fan Zhang , Pablo de Lara , John Griffin , Deepak Kumar Jain , Michael Shamis , Nagadheeraj Rottela , Srikanth Jampala , Ankur Dwivedi , Jay Zhou , Lee Daly , Sunila Sahu , Nipun Gupta , Liang Ma , Peter Mccarthy , Tianfei zhang , Satha Koteswara Rao Kottidi , Xiaoyun Li , Bernard Iremonger , Vladimir Medvedkin , David Hunt , Reshma Pattan , Byron Marohn , Sameh Gobriel , Yipeng Wang , Honnappa Nagarahalli , Robert Sanford , Kevin Laatz , Maryam Tahhan , Ori Kam , Radu Nicolau , Tomasz Kantecki , Sunil Kumar Kori , Pavan Nikhilesh Bhagavatula , Kirill Rybalchenko , "Kadam, Pallavi" Content-Type: text/plain; charset="UTF-8" Subject: Re: [dpdk-dev] [RFC] DPDK Trace support X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Fri, Jan 17, 2020 at 4:14 PM David Marchand wrote: > > On Fri, Jan 17, 2020 at 10:52 AM Jerin Jacob wrote: > > > > If someone needs more time to think through or any clarification is > > > > required then please discuss. > > > > > > I did not find the time to look at this. > > > Some quick questions: > > > - is LTTng coming with out-of-tree kmod? making it hard to support in > > > distributions? > > > > LTTng kernel tracing only needs kmod support. > > For the userspace tracing at minium following libraries are required. > > > > a) LTTng-UST > > b) LTTng-tools > > c) liburcu > > d) libpopt-dev > > > > Based on the https://lttng.org/docs/v2.11/#doc-installing-lttng > > -------------------------- 8<---------------------------------- > > Important:As of 22 October 2019, LTTng 2.11 is not available as > > distribution packages, except for Arch Linux. > > You can build LTTng 2.11 from source to install and use it. > > -------------------------- >8---------------------------------- > > Would there be requirements on a specific version of LTTng? No. If possible we would need a single trace format that works across multiple OS(that DPDK support(FreeBSD and Windows) to support post analysis and viewer tools. Current LTTng concern is only lacking all OS support and performance. > I can see RHEL 7 comes with version 2.4.1, RHEL 8 has 2.8.1. > > > > > - I have been playing with perf those days to track live processes and > > > gathering informations/stats at key point of a dpdk app without adding > > > anything in the binary. What does LTTng provide that scripting around > > > perf would not solve? > > > > Profiler and Tracer are two different things: Perf is a profiler. > > Are you sure you can draw such a line about perf? > You can add dynamic tracepoints with context in a live process (perf > probe/perf recordma), I used this to track where a variable was > getting updated once for a given device in OVS (and getting the number > of occurrences). > > I know there are limitations with perf (some static variables not > being caught, can be tricky to trace inlines). > Maybe LTTng is better at this since you put markers in your code. it is not like perf probe where it updates only the event. Trace will spit out all the information when trace is enabled on the tracepoint. For instance if we add _tracepoint_ for rte_eth_dev_configure(), I will spit out the, a) timestamp when it is called b) which cpu it called c) trace ID- rte_eth_dev_configure d) port_id e) nb_rx_q f) nb_tx_q, g) contents of const struct rte_eth_conf *dev_conf. > > > One thing of interest, I understand that LTTng does not require a > context switch when tracing. > That is an advantage over perf. > > > -- > David Marchand >