From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6424DC43460 for ; Tue, 20 Apr 2021 13:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F39A6101C for ; Tue, 20 Apr 2021 13:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232483AbhDTNaA (ORCPT ); Tue, 20 Apr 2021 09:30:00 -0400 Received: from mail.efficios.com ([167.114.26.124]:33372 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232295AbhDTN37 (ORCPT ); Tue, 20 Apr 2021 09:29:59 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id A740D2FE916; Tue, 20 Apr 2021 09:29:27 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 3m9Gwf_gMSRu; Tue, 20 Apr 2021 09:29:27 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 37A4F2FED9B; Tue, 20 Apr 2021 09:29:27 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 37A4F2FED9B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1618925367; bh=QsxHLQuZ6/NmxdwKl3bSdvfvXYh8C1ZBM9eOhl6zdvc=; h=Date:From:To:Message-ID:MIME-Version; b=W13i74aXhgRV/poLcJPrRQkcqPt2WSqaN0cI+vQiU5C9DMd4vWvKN8rO9lEmZl6gi 8tnGknzEh8o3FYv3mssQtpK2AhjCCGuxLYqOcsfr3GKvwX53Wc59s0cV9NFXl6NraV cfsm8VBVNtBH5L6w/wtR0g1Et0jmLyXNu1j5y84u83tGE0N4zWjF5ZRX+z1kIV3Uwm MX4qUntdQAnGa/N2vjVaIPMXkNISOWp+tvvKWsCVjf9cyEIPrppnOEpR5v1Wj2ybXj rWU5hYzqcLjGdQWrrpNuz5rsOpUOSOXl9MNi5VELORBIa3rDqhPl8LJBWIgleOYtvI qpMkn09ksCaKg== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id cwFy8b8gn99W; Tue, 20 Apr 2021 09:29:27 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 255132FED21; Tue, 20 Apr 2021 09:29:27 -0400 (EDT) Date: Tue, 20 Apr 2021 09:29:27 -0400 (EDT) From: Mathieu Desnoyers To: rostedt Cc: Dan Williams , fweisbec , Jessica Yu , linux-kernel , Ingo Molnar , chris@chris-wilson.co.uk, yuanhan liu , "Grumbach, Emmanuel" Message-ID: <1154727029.2004.1618925367044.JavaMail.zimbra@efficios.com> In-Reply-To: <20210420085532.4062b15e@gandalf.local.home> References: <1299622684.20306.77.camel@gandalf.stny.rr.com> <20130813111442.632f3421@gandalf.local.home> <87siybk8yl.fsf@rustcorp.com.au> <20130814233228.778f25d0@gandalf.local.home> <77a6e40b57df092d1bd8967305906a210f286111.camel@intel.com> <20210419181111.5eb582e8@gandalf.local.home> <20210420085532.4062b15e@gandalf.local.home> Subject: Re: [PATCH][RFC] tracing: Enable tracepoints via module parameters MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_4018 (ZimbraWebClient - FF87 (Linux)/8.8.15_GA_4007) Thread-Topic: tracing: Enable tracepoints via module parameters Thread-Index: sM+iKvNdasbLkp1rglxClIfh9BgdaA== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- On Apr 20, 2021, at 8:55 AM, rostedt rostedt@goodmis.org wrote: [...] > > Would adding automatic module parameters be an issue? That is, you can add > in the insmod command line a parameter that will enable tracepoints. We > could have a way to even see them from the modinfo. I think I had that > working once, and it wasn't really that hard to do. There is one thing we should consider here in terms of namespacing: those module command line parameters should be specific to each tracer (e.g. ftrace, perf, ebpf). LTTng for instance already tackles early module load tracing in a different way: users can enable instrumentation of yet-to-be loaded kernel modules. So it would not make sense in that scheme to have module load parameters. It's a different trade-off in terms of error reporting though: for instance, LTTng won't report an error if a user does a typo when entering an event name. So I think those command line parameters should be tracer-specific, do you agree ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com