From owner-cvs-src@FreeBSD.ORG Tue Apr 8 07:16:21 2003 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 55A8737B401; Tue, 8 Apr 2003 07:16:21 -0700 (PDT) Received: from mailout07.sul.t-online.com (mailout07.sul.t-online.com [194.25.134.83]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1C7DA43F93; Tue, 8 Apr 2003 07:16:20 -0700 (PDT) (envelope-from Alexander@Leidinger.net) Received: from fwd10.sul.t-online.de by mailout07.sul.t-online.com with smtp id 192ttO-0002iK-0E; Tue, 08 Apr 2003 16:16:06 +0200 Received: from Andro-Beta.Leidinger.net (520065502893-0001@[80.131.125.201]) by fmrl10.sul.t-online.com with esmtp id 192tsw-1yjrSiC; Tue, 8 Apr 2003 16:15:38 +0200 Received: from Magelan.Leidinger.net (Magelan [192.168.1.1]) h38EFeBR002209; Tue, 8 Apr 2003 16:15:41 +0200 (CEST) (envelope-from Alexander@Leidinger.net) Received: from Magelan.Leidinger.net (netchild@localhost [127.0.0.1]) by Magelan.Leidinger.net (8.12.9/8.12.9) with SMTP id h38EFlpr005308; Tue, 8 Apr 2003 16:15:47 +0200 (CEST) (envelope-from Alexander@Leidinger.net) Date: Tue, 8 Apr 2003 16:15:47 +0200 From: Alexander Leidinger To: Dag-Erling Smorgrav Message-Id: <20030408161547.1963e23a.Alexander@Leidinger.net> In-Reply-To: References: <20030408152227.60c38ce3.Alexander@Leidinger.net> <200304081327.h38DR9XC025406@spider.deepcore.dk> <20030408153259.2a4b03ac.Alexander@Leidinger.net> X-Mailer: Sylpheed version 0.8.9claws (GTK+ 1.2.10; i386-portbld-freebsd5.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Sender: 520065502893-0001@t-dialin.net cc: cvs-src@freebsd.org cc: src-committers@freebsd.org cc: sos@spider.deepcore.dk cc: cvs-all@freebsd.org cc: sos@freebsd.org Subject: Re: cvs commit: src/sys/dev/ata ata-all.c ata-all.h ata-chipset.cata-dma.c ata-pci.c ata-pci.h X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Apr 2003 14:16:21 -0000 On Tue, 08 Apr 2003 15:54:43 +0200 Dag-Erling Smorgrav wrote: > Alexander Leidinger writes: > > Does this mean we can't use ATA-TQ in situations where we would use TQ > > without WC on a SCSI system (read: does it affect softupdates)? > > Tagged queueing doesn't make sense without a write cache. Think about > it for a minute. It doesn't make sense without some kind of a buffer, I know. With SCSI disks you can observe a small difference between TQ with WC enabled and TQ with WC disabled. Based upon this I concluded, that SCSI disks seems to have a buffer for the WC (with all it's ill side effects in the softupdates case) and another buffer for TQ. SCSI != ATA, but why design another WC/TQ combination, if I can borrow it from the SCSI disks... Feel free to correct misunderstandings on my side. Bye, Alexander. -- "One world, one web, one program" -- Microsoft promotional ad "Ein Volk, ein Reich, ein Fuehrer" -- Adolf Hitler http://www.Leidinger.net Alexander @ Leidinger.net GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7