Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761507AbYBZI4a (ORCPT ); Tue, 26 Feb 2008 03:56:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759089AbYBZI4I (ORCPT ); Tue, 26 Feb 2008 03:56:08 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58930 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756659AbYBZI4G (ORCPT ); Tue, 26 Feb 2008 03:56:06 -0500 Date: Tue, 26 Feb 2008 09:55:41 +0100 From: Ingo Molnar To: Pekka Enberg Cc: Nicholas Miell , Andrew Morton , Arjan van de Ven , linux-kernel@vger.kernel.org, sandmann@redhat.com, tglx@tglx.de, hpa@zytor.com, levon@movementarian.org Subject: Re: [PATCH] x86: add the debugfs interface for the sysprof tool Message-ID: <20080226085541.GE9857@elte.hu> References: <20080219123756.6261c13c@laptopd505.fenrus.org> <20080223001130.d8922136.akpm@linux-foundation.org> <84144f020802230351o24b11282vbb1cecf518d91825@mail.gmail.com> <20080223104611.a3430285.akpm@linux-foundation.org> <47C0DB2E.5000404@cs.helsinki.fi> <1203822747.2439.1.camel@entropy> <84144f020802252227t729e8b0bif9c3c65e17304fd1@mail.gmail.com> <84144f020802252248g7aa7c8dbx9ddf389f3962f836@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <84144f020802252248g7aa7c8dbx9ddf389f3962f836@mail.gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) 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: 1198 Lines: 29 * Pekka Enberg wrote: > Hi, > > On Tue, Feb 26, 2008 at 8:27 AM, Pekka Enberg wrote: > > > You could try passing the --callgraph option to opcontrol. > > > > Hmm, perhaps I am missing something but I don't think that does what > > sysprof does. At least I can't find where in the oprofile kernel code > > does it save the full stack trace for user-space. John? > > Ok, so as pointed out by Nicholas/Andrew, oprofile does indeed do > exactly what sysprof does (see > arch/x86/oprofile/backtrace.c::backtrace_address, for example). So, > Soeren, any other reason we can't use the oprofile kernel module for > sysprof? as i pointed it out earlier in the thread, the oprofile implementation seems buggy because when an event comes from NMI context __copy_from_user_inatomic() can fault and re-enable NMIs - causing possible stack recursion/corruption. Does not look like an easy fix. 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/