From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26916 invoked by alias); 30 Jun 2008 20:49:14 -0000 Received: (qmail 26906 invoked by uid 22791); 30 Jun 2008 20:49:13 -0000 X-Spam-Status: No, hits=-2.2 required=5.0 tests=AWL,BAYES_00,RDNS_DYNAMIC X-Spam-Check-By: sourceware.org Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net (HELO sunset.davemloft.net) (74.93.104.97) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 30 Jun 2008 20:48:46 +0000 Received: from localhost (localhost [127.0.0.1]) by sunset.davemloft.net (Postfix) with ESMTP id 1B147C8D0A6; Mon, 30 Jun 2008 13:48:45 -0700 (PDT) Date: Mon, 30 Jun 2008 23:02:00 -0000 Message-Id: <20080630.134844.34119775.davem@davemloft.net> To: acme@redhat.com Cc: tytso@mit.edu, fche@redhat.com, ksummit-2008-discuss@lists.linux-foundation.org, systemtap@sources.redhat.com Subject: Re: [Ksummit-2008-discuss] DTrace From: David Miller In-Reply-To: <20080630202233.GC15832@ghostprotocols.net> References: <20080630192533.GE21660@redhat.com> <20080630201031.GF7988@mit.edu> <20080630202233.GC15832@ghostprotocols.net> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2008-q2/txt/msg00819.txt.bz2 From: Arnaldo Carvalho de Melo Date: Mon, 30 Jun 2008 17:22:33 -0300 > Em Mon, Jun 30, 2008 at 04:10:31PM -0400, Theodore Tso escreveu: > > On Mon, Jun 30, 2008 at 03:25:33PM -0400, Frank Ch. Eigler wrote: > > Stupid question --- has anyone thought about writing tools to strip > > out specific debug information not needed by Systemtap? For example, > > I assume systemtap doesn't need the line number information, since you > > can't set probes on arbitrary line numbers (and even if you could, > > such tapsets would be so brittle that it wouldn't be funny); so would > > the debuginfo files be smaller if that information were stripped out? > > I understand that this would make the files less useful for > > kdump/crash, but for systemtap only users, it might be quite useful. > > What about stripping out the text segment of the object files, so you > > aren't storing the information twice on disk, or compressing the > > debuginfo files so they take up less room on disk? > > Yes, its called CTF, Compressed C Type Format, in DTrace land: > > http://opensolaris.org/os/project/ppc-dev/task_map/ctf/ > > DaveM wrote a CTF loader that I included in my dwarves package, so that > we can pretty-print and use all the other features in pahole on files > with CTF sections, such as the Open Solaris kernel and the userland > binaries, that all ship with CTF embedded, dispensing the usage of > -debuginfo packages, all AFAIK. One thing you lose with CTF is the stack unwind tables, and I don't know if systemtap needs that or not. If someone can state what the absolute minimum requirement is for systemtap to be able to analyze a binary properly, we can figure out if CTF provides it.