From owner-freebsd-stable@FreeBSD.ORG  Sat Mar  6 16:00:12 2010
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id A2F4A106564A;
	Sat,  6 Mar 2010 16:00:12 +0000 (UTC)
	(envelope-from rwatson@FreeBSD.org)
Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42])
	by mx1.freebsd.org (Postfix) with ESMTP id 759BA8FC12;
	Sat,  6 Mar 2010 16:00:12 +0000 (UTC)
Received: from fledge.watson.org (fledge.watson.org [65.122.17.41])
	by cyrus.watson.org (Postfix) with ESMTPS id 20E8E46B4C;
	Sat,  6 Mar 2010 11:00:12 -0500 (EST)
Date: Sat, 6 Mar 2010 16:00:12 +0000 (GMT)
From: Robert Watson <rwatson@FreeBSD.org>
X-X-Sender: robert@fledge.watson.org
To: Alexander Leidinger <Alexander@Leidinger.net>
In-Reply-To: <20100306164451.00001999@unknown>
Message-ID: <alpine.BSF.2.00.1003061558520.59375@fledge.watson.org>
References: <E1Nnv0H-00020A-9M@kabab.cs.huji.ac.il>
	<alpine.BSF.2.00.1003061508020.16631@fledge.watson.org>
	<20100306164451.00001999@unknown>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: freebsd-stable@freebsd.org, jhb@FreeBSD.org
Subject: Re: is dtrace usable?
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 06 Mar 2010 16:00:12 -0000

On Sat, 6 Mar 2010, Alexander Leidinger wrote:

>> Take a look at the DTrace configuration information here:
>>
>>    http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/dtrace.html
>
> I've just reread it (despite the fact that I already used it). Some
> comments:
>
> Last time I tried, I didn't see any problems by adding
>  makeoptions     WITH_CTF=yes
> to the kernel config instead of doing
>  make WITH_CTF=1 kernel
>
> Did I miss something, and if not, shouldn't we tell about the
> makeoptions part instead (a kernel rebuild later will not cause
> trouble when someone forgets to do the WITH_CTF part as it is already
> in the kernel makefile)?

I'll leave John to answer this one, CC line broadended.

> What is DDB_CTF doing? Some additional dtrace access in ddb? I didn't had it 
> before but the dtrace probes I had in KLDs worked without problems when 
> running dtrace probes from userland.

This is a poorly named kernel option, and should probably be changed.  This 
has to do with the kernel loading CTF information for kernel modules.  My 
recollection is hazy, but it may well be required in order for fbt to be used 
with modules.

Robert N M Watson
Computer Laboratory
University of Cambridge