Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758118AbYHOJY5 (ORCPT ); Fri, 15 Aug 2008 05:24:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753684AbYHOJYs (ORCPT ); Fri, 15 Aug 2008 05:24:48 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:56634 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483AbYHOJYr (ORCPT ); Fri, 15 Aug 2008 05:24:47 -0400 Date: Fri, 15 Aug 2008 11:24:12 +0200 From: Ingo Molnar To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Andrew Morton , Linus Torvalds , David Miller , Mathieu Desnoyers , Roland McGrath , Ulrich Drepper , Rusty Russell , Jeremy Fitzhardinge , Gregory Haskins , Arnaldo Carvalho de Melo , "Luis Claudio R. Goncalves" , Clark Williams , Bruce Duncan , Marcin Slusarz , Steven Rostedt Subject: Re: [PATCH v2 0/6] ftrace: to kill a daemon (small updates) Message-ID: <20080815092412.GC22209@elte.hu> References: <20080814194506.233473381@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080814194506.233473381@goodmis.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1941 Lines: 51 * Steven Rostedt wrote: > [ > Changes since v1: > > regex fix in x86_64 recordmcount.pl. Now it can handle all > mcount+0x... mcount-0x... and mcount, where as the original > only handled mcount+0x... > > Made mcount on start-up to simply return. The current mcount > is set up to be replaced with a call to ftrace_record_ip. > This is no longer necessary. > > Note: This patch series is focusing on how calls to mcount in > the kernel are converted to nops. It does not address what > kind of nop is used. That is a different topic, and should > be in a different patch series. > > Note 2: I have found that the changes here are more stable than > the current daemon method, and these patches should be used. > It also solves the resume from suspend to ram bug that was > reported: > > http://lkml.org/lkml/2008/8/12/234 > and > http://lkml.org/lkml/2008/8/12/451 > > Note 3: I have already ported this to PowerPC64, but I am waiting > for this to be accepted first before submitting those changes. > ] > > One of the things that bothered me about the latest ftrace code was > this annoying daemon that would wake up once a second to see if it had > work to do. If it did not, it would go to sleep, otherwise it would do > its work and then go to sleep. i like this concept alot - i've applied the whole lot to tip/tracing/ftrace. Eventually gcc should be extended to provide a separate section for instrumentation patch sites, instead of us having to disassemble the object code. That would also make the ftrace build faster. Any gcc folks interested in that? 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/