From owner-freebsd-current@FreeBSD.ORG Tue Apr 6 01:14:44 2004 Return-Path: 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 8FC2F16A4CE for ; Tue, 6 Apr 2004 01:14:44 -0700 (PDT) Received: from osiris.ipform.ru (osiris.itlegion.ru [212.248.52.90]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE3A343D2D for ; Tue, 6 Apr 2004 01:14:43 -0700 (PDT) (envelope-from matrix@itlegion.ru) Received: from artem (artem.office.ipform.ru [192.168.0.12]) by osiris.ipform.ru (8.12.6/8.12.6) with ESMTP id i368EXXg032780; Tue, 6 Apr 2004 12:14:34 +0400 (MSD) (envelope-from matrix@itlegion.ru) X-AntiVirus: Checked by Dr.Web (http://www.drweb.net) Message-ID: <004101c41bae$a9a419e0$0c00a8c0@artem> From: "Artem Koutchine" To: "Andy Farkas" , "Xin LI" References: <009401c41ba5$3b000f70$0c00a8c0@artem> <20040406071205.GA2819@frontfree.net> <20040406174155.S56300@hewey.af.speednet.com.au> Date: Tue, 6 Apr 2004 12:10:40 +0400 Organization: IT Legion MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 cc: freebsd-current@freebsd.org Subject: Re: Qustion about being "Giant-locked" X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 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: Tue, 06 Apr 2004 08:14:44 -0000 >From: "Andy Farkas" >Sent: Tuesday, April 06, 2004 11:56 AM > On Tue, 6 Apr 2004, Xin LI wrote: > > On Tue, Apr 06, 2004 at 11:03:13AM +0400, Artem Koutchine wrote: > > > While booting i see many drivers marked > > > as [Giant-locked]. > > > Is being Giant-locked good or bad what are the > > > implications? > > It's not good if you have a computer with multiple processors. > > I have a box with 4 ppro-200 cpus. It has 4 adaptec eisa scsi controllers, > each controlling 2 disks. All 8 disks are in the same vinum raid-5 volume. > I have a large (1.5gig) file on this volume. > > This is what happens when I run md5 on this file 4 times concurrently: > > > As you can see, only 8% of all cpus are being used to calculate the md5s. > At least 2 cpus are constantly idle. > > > ahc5: [GIANT-LOCKED] > atkbd0: [GIANT-LOCKED] I am trying to get your point and i really can't. I just don't see what your are trying to say. If you refer to 8% CPU usage then i see that it is only 8% because SCSI is the bottleneck. Disk just do not give data fast enough to load CPU high. Also, i don't think the do not give data fast enough only because of the Giant. I think it is mostly scsi and hdd speed problem in this case. Afterall md5 algorithm is not too havy on cpu anyway. Artem