From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760221Ab3LIKMP (ORCPT ); Mon, 9 Dec 2013 05:12:15 -0500 Received: from mail7.hitachi.co.jp ([133.145.228.42]:58971 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755530Ab3LIKMN (ORCPT ); Mon, 9 Dec 2013 05:12:13 -0500 Message-ID: <52A59775.9050206@hitachi.com> Date: Mon, 09 Dec 2013 19:12:05 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: "Frank Ch. Eigler" Cc: Jovi Zhangwei , Alexei Starovoitov , Steven Rostedt , Ingo Molnar , Peter Zijlstra , "H. Peter Anvin" , Thomas Gleixner , Tom Zanussi , Eric Dumazet , LKML , "yrl.pp-manager.tt@hitachi.com" Subject: Re: [RFC PATCH tip 4/5] use BPF in tracing filters References: <1386044930-15149-1-git-send-email-ast@plumgrid.com> <1386044930-15149-5-git-send-email-ast@plumgrid.com> <529E7BEC.70509@hitachi.com> <20131203201133.52934a02@gandalf.local.home> <529FC352.7090004@hitachi.com> <52A18E31.6030605@hitachi.com> <52A26268.5070403@hitachi.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2013/12/09 3:22), Frank Ch. Eigler wrote: > > masami.hiramatsu.pt wrote: > >> [...] >> Anyway, as far as I can see, there looks be two different models of >> tracing in our mind. >> >> A) Fixed event based tracing: In this model, there are several fixed >> "events" which well defined with fixed arguments. tracer handles these >> events and only use limited arguments. It's like a packet stream >> processing. ftrace, perf etc. are used this model. >> >> B) Flexible event-point tracing: In this model, each tracer(or even >> trace user) can freely define their own event, there will be some fixed >> tracing points defined, but arguments are defined by users. It's like a >> debugger's breakpoint debugging. systemtap, ktap etc. are used this model. > > It may be more useful to think of it as a contrast along the > hard-coded versus programmable axis. (perf, systemtap, and ktap can > each reach to some extent across your "fixed" vs "flexible" line. > Each has some dynamic and some static-tracepoint capability.) Oh, I meant that B is not tend to share the defined event among different tracing instances. Each instances defines new different dynamic events and gets memories and registers freely. OTOH, the Ftrace and LTT models are based on the fixed, shared and well defined events. Even if a new dynamic event is defined, it will be shared by every instances. > >> e.g. B model has a good flexibility and A model is easy to use for >> beginners. > > I don't think it's the model that dictates ease-of-use, but the > quality of implementation, logistics, documentation, and examples. Of course, but it requires learning the new programming way. And also, we need to know about the target source code for setting up new events. I know that the systemtap provides many pre-defined probepoints. so, the systemtap may already have solved this kind of issue. ;) Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com