From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16594 invoked by alias); 24 Jul 2005 20:57:04 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 16585 invoked by uid 22791); 24 Jul 2005 20:57:00 -0000 Received: from pop06.mail.atl.earthlink.net (HELO pop06.mail.atl.earthlink.net) (207.69.200.40) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Sun, 24 Jul 2005 20:57:00 +0000 Received: from h-68-164-109-9.dnvtco56.dynamic.covad.net ([68.164.109.9]) by pop06.mail.atl.earthlink.net with esmtp (Exim 3.36 #10) id 1DwnWs-000322-00; Sun, 24 Jul 2005 16:56:59 -0400 Subject: gprof & Linux interaction oddity From: Tres Melton To: gdb-patches@sources.redhat.com Cc: John Mylchreest Content-Type: text/plain Date: Sun, 24 Jul 2005 20:57:00 -0000 Message-Id: <1122238617.10644.44.camel@thor.tres.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-SW-Source: 2005-07/txt/msg00172.txt.bz2 Gentlemen, There is an issue with gprof and getting the current OS' Hz from the elf header in Linux via sysconf(). That value is always set to 100 Hz and it is playing games with profiling code. I have been in contact with a number of the kernel developers and we are preparing to take this issue to the LKML. There is a bug on RedHat's bugzilla regarding this issue and a more detailed report in Gentoo's bugzilla: http://bugs.gentoo.org/show_bug.cgi?id=90090 https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=151763 Most of the developers that I have spoken with, including Andrew Morton and John Mylchreest, are in favor of correcting this issue but Linus has previously ruled against it. We are hoping that he will reconsider since the merging of the configurable user hz patch in 2.6.13-rc3. One of the developers, Robert Love, has responded: "Explain why gprof needs to know the _actual_ timing tick." I was hoping that you could help me with that. Thanks for your help, -- Tres