From owner-freebsd-current@FreeBSD.ORG Wed Jun 14 14:25:54 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B225C16A41A for ; Wed, 14 Jun 2006 14:25:54 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by mx1.FreeBSD.org (Postfix) with ESMTP id 063DD43D45 for ; Wed, 14 Jun 2006 14:25:53 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from zion.baldwin.cx (zion.baldwin.cx [192.168.0.7]) (authenticated bits=0) by server.baldwin.cx (8.13.4/8.13.4) with ESMTP id k5EEPoiK033749; Wed, 14 Jun 2006 10:25:52 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: freebsd-current@freebsd.org Date: Wed, 14 Jun 2006 10:20:21 -0400 User-Agent: KMail/1.9.1 References: <20060613021543.GA71283@what-creek.com> <20060613213617.GA78337@what-creek.com> In-Reply-To: <20060613213617.GA78337@what-creek.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200606141020.22182.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [192.168.0.1]); Wed, 14 Jun 2006 10:25:53 -0400 (EDT) X-Virus-Scanned: ClamAV 0.87.1/1538/Tue Jun 13 16:17:56 2006 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on server.baldwin.cx Cc: John Birrell Subject: Re: DTrace for FreeBSD - fbt output X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Jun 2006 14:25:54 -0000 On Tuesday 13 June 2006 17:36, John Birrell wrote: > On Tue, Jun 13, 2006 at 02:15:43AM +0000, John Birrell wrote: > > With the development as it stands at the moment, take care using the FBT > > provider because you can easily cause the system to go kaboom. I'm still > > trying to track down the problems there. It's not in FBT itself -- just > > the fact that the DTrace probe context isn't allowed to call anything t= hat > > FBT can instrument. If that happens you will either get a reboot or a > > double fault will leave you in kdb. I recommend only enabling a few FBT > > probes at a time just so you know which ones could cause a fault. There= is > > no point telling me that you enabled fbt::: and the system went kaboom! >=20 > With the FBT provider as it now stands and using this script: >=20 > fbt:::entry > { > @[probefunc] =3D count(); > } >=20 > the output after a buildworld is listed below. Check out the number of > calls to critical_enter and critical_exit (which are listed at the bottom= )! > And for comparison, check the hardclock() count which relects 1000 Hz. Those functions are called a lot as every spinlock ends up calling them (including sched_lock, turnstile chain locks, sleepqueue locks, etc.) One thing I found odd is: > cpu_set_fork_handler 608 > kthread_create 608 > kthread_exit 608 We created and destroyed 608 kernel threads during a buildworld?? This doesn't seem right. Were you doing the buildworld over NFS? =2D-=20 John Baldwin =A0<>< =A0http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" =A0=3D =A0http://www.FreeBSD.org