From owner-freebsd-stable@FreeBSD.ORG  Sat Oct 20 19:30:17 2007
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 2D9EF16A475;
	Sat, 20 Oct 2007 19:30:17 +0000 (UTC)
	(envelope-from bright@elvis.mu.org)
Received: from elvis.mu.org (elvis.mu.org [192.203.228.196])
	by mx1.freebsd.org (Postfix) with ESMTP id 5749813C48A;
	Sat, 20 Oct 2007 19:27:23 +0000 (UTC)
	(envelope-from bright@elvis.mu.org)
Received: by elvis.mu.org (Postfix, from userid 1192)
	id 6CD381A4D91; Sat, 20 Oct 2007 12:27:17 -0700 (PDT)
Date: Sat, 20 Oct 2007 12:27:17 -0700
From: Alfred Perlstein <alfred@freebsd.org>
To: Robert Watson <rwatson@FreeBSD.org>
Message-ID: <20071020192717.GX31826@elvis.mu.org>
References: <20071019232846.GQ31826@elvis.mu.org>
	<4719B06F.3000103@FreeBSD.org>
	<20071020181811.W70919@fledge.watson.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20071020181811.W70919@fledge.watson.org>
User-Agent: Mutt/1.4.2.3i
Cc: Kris Kennaway <kris@FreeBSD.org>, stable@freebsd.org, jhb@freebsd.org
Subject: Re: LOCK_PROFILING in -stable
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, 20 Oct 2007 19:30:17 -0000

* Robert Watson <rwatson@FreeBSD.org> [071020 10:21] wrote:
> 
> On Sat, 20 Oct 2007, Kris Kennaway wrote:
> 
> >Alfred Perlstein wrote:
> >>Hey guys, I have LOCK_PROFILING done for a product based on FreeBSD-6, 
> >>this means I can relatively easily backport LOCK_PROFILING from FreeBSD-7 
> >>to FreeBSD-6.
> >>
> >>Do we want this?
> >>
> >>I'd like to do it if people want it.
> >
> >I think it should be done, performance is a lot better than the old 6.x 
> >version and it also adds another very useful performance metric (time 
> >spent waiting for the lock).  The only concern is that it doesn't break 
> >ABI support when not compiled in, but I'm pretty sure you've already told 
> >me this is OK. Thanks for looking at this.
> 
> This is my feeling also -- I would consider ABI breakage a show stopper for 
> 6.x, but feel otherwise that the new code is much more mature and capable 
> and would be quite beneficial to people building appliances and related 
> products on 6.x. You might check with Attilio about whether there are any 
> remaining outstanding issues that need to be resolved first, and make sure 
> to send a heads up out on stable@ and put a note in UPDATING that the 
> option and details have changed.

I still get confused as to the meaning of this...

It only breaks ABI when it's enabled.

I think that is OK, right?

-- 
- Alfred Perlstein