Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759731AbYHICDz (ORCPT ); Fri, 8 Aug 2008 22:03:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753330AbYHICDq (ORCPT ); Fri, 8 Aug 2008 22:03:46 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:53019 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753032AbYHICDp (ORCPT ); Fri, 8 Aug 2008 22:03:45 -0400 Date: Fri, 8 Aug 2008 22:03:42 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Andi Kleen cc: Mathieu Desnoyers , LKML , Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Andrew Morton , Linus Torvalds , David Miller , Roland McGrath , Ulrich Drepper , Rusty Russell , Jeremy Fitzhardinge , Gregory Haskins , Arnaldo Carvalho de Melo , "Luis Claudio R. Goncalves" , Clark Williams Subject: Re: [PATCH 0/5] ftrace: to kill a daemon In-Reply-To: <20080809015539.GG9038@one.firstfloor.org> Message-ID: References: <20080808174607.GG8244@Krystal> <20080808182104.GA11376@Krystal> <20080808190506.GD11376@Krystal> <87tzdv2g05.fsf@basil.nowhere.org> <20080809011955.GE9038@one.firstfloor.org> <20080809015539.GG9038@one.firstfloor.org> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 996 Lines: 29 On Sat, 9 Aug 2008, Andi Kleen wrote: > > Funny, CONFIG_FTRACE happens to select that. Now the question is, would > > mcount work without it? > > Not without fixing gcc first. It would work if gcc always called > mcount the first thing before setting up the stack frame. Not > sure why it doesn't do that. I could take out the frame pointer option and pass in zero for the parent in such that case. But the parent is quite useful. But if it helps with performance, it may be worth doing this. -- Steve > > Still do a benchmark of frame pointer vs no frame pointer kernel > and you'll see, especially on a older CPUs without special hardware > to avoid stack stalls (e.g. not Core2) I'll see what it does with just a kernel build. -- Steve -- 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/