From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754128AbXKVMBQ (ORCPT ); Thu, 22 Nov 2007 07:01:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752390AbXKVMBE (ORCPT ); Thu, 22 Nov 2007 07:01:04 -0500 Received: from tomts40.bellnexxia.net ([209.226.175.97]:35923 "EHLO tomts40-srv.bellnexxia.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751506AbXKVMBD (ORCPT ); Thu, 22 Nov 2007 07:01:03 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ah4FAIb+REdMROHU/2dsb2JhbACBWw Date: Thu, 22 Nov 2007 07:00:56 -0500 From: Mathieu Desnoyers To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Andrew Morton , Mike Mason , Dipankar Sarma Subject: Re: [PATCH] Linux Kernel Markers - Support Multiple Probes Message-ID: <20071122120056.GA6134@Krystal> References: <20071122034126.GA24898@Krystal> <20071122100658.GA2738@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20071122100658.GA2738@infradead.org> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 06:57:19 up 18 days, 17:02, 3 users, load average: 1.20, 0.81, 0.67 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Christoph Hellwig (hch@infradead.org) wrote: > On Wed, Nov 21, 2007 at 10:41:26PM -0500, Mathieu Desnoyers wrote: > > RCU style multiple probes support for the Linux Kernel Markers. > > Why would we want this? > If we want to have more than one probe connected to a marker at a given time (LTTng, or blktrace, ssytemtap) then we need this patch. Without it, connecting a second probe handler to a marker will fail. It allow us, for instance, to do interesting combinations : Do standard tracing with LTTng and, eventually, to compute statistics with SystemTAP, or to have a special trigger on an event that would call a systemtap script which would stop flight recorder tracing. Mathieu -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68