Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933539AbZAPQar (ORCPT ); Fri, 16 Jan 2009 11:30:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760789AbZAPQag (ORCPT ); Fri, 16 Jan 2009 11:30:36 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:53855 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760771AbZAPQaf (ORCPT ); Fri, 16 Jan 2009 11:30:35 -0500 Date: Fri, 16 Jan 2009 17:30:21 +0100 From: Ingo Molnar To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Andrew Morton , Frederic Weisbecker , Chris Mason Subject: Re: [PATCH 0/2] ftrace: updates to tip Message-ID: <20090116163021.GA27495@elte.hu> References: <20090116004050.273665842@goodmis.org> <20090116112345.GC20082@elte.hu> <20090116152103.GA28643@elte.hu> <20090116160202.GA15209@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.2.3 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4709] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 31 * Steven Rostedt wrote: > On Fri, 16 Jan 2009, Ingo Molnar wrote: > > * Steven Rostedt wrote: > > > > [...] We can register a function to be traced via the function pointer, > > > and we can pick which functions to trace, but we can not separate out > > > different functions for different traces. > > > > Why not? We could have a hash of all traced functions with metadata > > attached. Since patching functions in/out would be a relatively rare > > operation, this would be a highly efficient read-mostly hash. > > I was afraid you would say that :-) > > Yes, we could add something to do this. It would take some thought on a > good api, and implementation. This is not an easy task by any means. We > need a way to map between a function call and a tracer, where a function > call can call more than one tracer. Note that some other things could be consolidated under per function metadata: for example set_graph_function - which really is a per function attribute too. Plus a lot of new things would be enabled i think. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/