From owner-freebsd-stable@FreeBSD.ORG Wed Oct 24 21:45:09 2007 Return-Path: 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 CAD1416A418; Wed, 24 Oct 2007 21:45:09 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from speedfactory.net (mail6.speedfactory.net [66.23.216.219]) by mx1.freebsd.org (Postfix) with ESMTP id 35DE413C4A6; Wed, 24 Oct 2007 21:45:08 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (unverified [66.23.211.162]) by speedfactory.net (SurgeMail 3.8p) with ESMTP id 215936903-1834499 for multiple; Wed, 24 Oct 2007 17:47:11 -0400 Received: from localhost.corp.yahoo.com (john@localhost [127.0.0.1]) (authenticated bits=0) by server.baldwin.cx (8.13.8/8.13.8) with ESMTP id l9OLiUD4097452; Wed, 24 Oct 2007 17:44:30 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: Kris Kennaway Date: Wed, 24 Oct 2007 16:08:08 -0400 User-Agent: KMail/1.9.6 References: <20071019232846.GQ31826@elvis.mu.org> <200710241310.22969.jhb@freebsd.org> <471FA0B4.1000904@FreeBSD.org> In-Reply-To: <471FA0B4.1000904@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710241608.09298.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [127.0.0.1]); Wed, 24 Oct 2007 17:44:30 -0400 (EDT) X-Virus-Scanned: ClamAV 0.88.3/4590/Wed Oct 24 11:20:13 2007 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on server.baldwin.cx Cc: stable@freebsd.org, Alfred Perlstein , Robert Watson 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 21:45:09 -0000 On Wednesday 24 October 2007 03:44:52 pm Kris Kennaway wrote: > John Baldwin wrote: > > On Sunday 21 October 2007 04:56:30 am Kris Kennaway wrote: > >> Alfred Perlstein wrote: > >>> * Robert Watson [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? > >>> > >> Yes, that is fine. Other existing debugging options also break ABI when > >> enabled, so it's OK. > > > > Well, MUTEX_PROFILING does and LOCK_PROFILING is the same thing. This option > > is a known "special case" that breaks the ABI and people using it should > > already be aware of that. Other debugging options (INVARIANTS, WITNESS, > > etc.) do not affect the ABI. > > > > DEBUG_VFS_LOCKS and/or DEBUG_LOCKS also break the ABI. True, but those are the exception rather than the rule. -- John Baldwin