Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757381AbcC2QEL (ORCPT ); Tue, 29 Mar 2016 12:04:11 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:47145 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752200AbcC2QEJ (ORCPT ); Tue, 29 Mar 2016 12:04:09 -0400 Date: Tue, 29 Mar 2016 18:04:01 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: Daniel Bristot de Oliveira , Ingo Molnar , Thomas Gleixner , Juri Lelli , Arnaldo Carvalho de Melo , LKML , linux-rt-users Subject: Re: [PATCH V2 3/3] sched/deadline: Tracepoints for deadline scheduler Message-ID: <20160329160401.GB3430@twins.programming.kicks-ass.net> References: <14f6caa05f73ceba69eff035ac542cad671552b3.1459182044.git.bristot@redhat.com> <20160329151649.GA12845@twins.programming.kicks-ass.net> <20160329115700.40acb336@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160329115700.40acb336@gandalf.local.home> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 803 Lines: 15 On Tue, Mar 29, 2016 at 11:57:00AM -0400, Steven Rostedt wrote: > Hmm, I probably could add tracing infrastructure that would let us > extend existing tracepoints. That is, without modifying sched_switch, > we could add a new tracepoint that when enabled, would attach itself to > the sched_switch tracepoint and record different information. Like a > special sched_switch_deadline tracepoint, that would record the existing > runtime,deadline and period for deadline tasks. It wont add more > tracepoints into the core scheduler, but use the existing one. Urgh; maybe. But I would would not want the new thing to be called _deadline, maybe _v{n} id anything and have a KERN_WARNING emitted when people enable the old one. Ideally we'd rename the old one, but I suspect even that would break stuff :/