From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765490AbYDOQbZ (ORCPT ); Tue, 15 Apr 2008 12:31:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754163AbYDOQbS (ORCPT ); Tue, 15 Apr 2008 12:31:18 -0400 Received: from e28smtp02.in.ibm.com ([59.145.155.2]:47986 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753822AbYDOQbR (ORCPT ); Tue, 15 Apr 2008 12:31:17 -0400 Date: Tue, 15 Apr 2008 21:43:49 +0530 From: "K. Prasad" To: Alexey Dobriyan Cc: Mathieu Desnoyers , Peter Zijlstra , prasad@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu, Christoph Hellwig , "Frank Ch. Eigler" Subject: Re: [RFC PATCH 1/2] Marker probes in futex.c Message-ID: <20080415161349.GA7444@in.ibm.com> Reply-To: prasad@linux.vnet.ibm.com References: <20080415115058.GA6788@in.ibm.com> <20080415115314.GA6975@in.ibm.com> <1208260942.6395.6.camel@twins> <20080415123233.GA19797@Krystal> <20080415125009.GA5573@martell.zuzino.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080415125009.GA5573@martell.zuzino.mipt.ru> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 15, 2008 at 04:50:09PM +0400, Alexey Dobriyan wrote: > On Tue, Apr 15, 2008 at 08:32:34AM -0400, Mathieu Desnoyers wrote: > > * Peter Zijlstra (a.p.zijlstra@chello.nl) wrote: > > > On Tue, 2008-04-15 at 17:23 +0530, K. Prasad wrote: > > > > > > > + trace_mark(futex_wait_called, "uaddr:%p fshared:%p val:%u " > > > > + "abs_time:%p bitset:%d", > > > > + uaddr, fshared, val, abs_time, bitset); > > > > > > This is some seriuosly ugly looking gunk, why would we want stuff like > > > that scattered across the code? > > > > > > > I don't really see how it differs so much from printks, which kernel > > developers are already familiar with. > > They aren't in every -E codepath, nor they are at the start > and at the end of every important function (like system call). > > Such printks are usually inserted during debugging when you don't care > about ugliness and these patches will eventually make kernel looks like > being permanently debugged one. > Wondering how useful would printks be when debugging large systems (say analysing futex contention on a 32-way CPU system)....also to mention the inability to do a binary dump of the interested data structures. --K.Prasad