From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752475AbZHIPQq (ORCPT ); Sun, 9 Aug 2009 11:16:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751305AbZHIPQp (ORCPT ); Sun, 9 Aug 2009 11:16:45 -0400 Received: from relay7.uol.com.br ([187.17.116.5]:52307 "EHLO relay7.uol.com.br" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827AbZHIPQp (ORCPT ); Sun, 9 Aug 2009 11:16:45 -0400 Date: Sun, 9 Aug 2009 12:14:58 -0300 From: =?utf-8?Q?Rog=C3=A9rio?= Brito To: linux-kernel@vger.kernel.org Subject: Confusing help regarding single-depth WCHAN output Message-ID: <20090809151458.GA32444@ime.usp.br> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.5.20 (2009-06-14) X-SIG5: 5ba9331d6c67fa58d75a351bcde8bdea Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. I noticed this some releases ago, but only now I was perusing the kernel with a little more attention and got very curious. When doing a "make menuconfig" on an amd64 system, I get the following message: ,---- | Single-depth WCHAN output | CONFIG_SCHED_OMIT_FRAME_POINTER: | | Calculate simpler /proc//wchan values. If this option | is disabled then wchan values will recurse back to the | caller function. This provides more accurate wchan values, | at the expense of slightly more scheduling overhead. | | If in doubt, say "Y". | | Symbol: SCHED_OMIT_FRAME_POINTER [=y] | Prompt: Single-depth WCHAN output | Defined at arch/x86/Kconfig:441 | Depends on: X86 | Location: | -> Processor type and features `---- Is the WCHAN option related to omitting a frame pointer? If yes, how could this be written in a more detailed way? Thanks for any comments, Rogério Brito. -- Rogério Brito : rbrito@{mackenzie,ime.usp}.br : GPG key 1024D/7C2CAEB8 http://www.ime.usp.br/~rbrito : http://meusite.mackenzie.com.br/rbrito Projects: algorithms.berlios.de : lame.sf.net : vrms.alioth.debian.org