From owner-freebsd-stable@FreeBSD.ORG Thu Sep 25 09:20:27 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 18BC516A4B3 for ; Thu, 25 Sep 2003 09:20:27 -0700 (PDT) Received: from carver.gumbysoft.com (carver.gumbysoft.com [66.220.23.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id BC7E244003 for ; Thu, 25 Sep 2003 09:20:23 -0700 (PDT) (envelope-from dwhite@gumbysoft.com) Received: by carver.gumbysoft.com (Postfix, from userid 1000) id A6BC672DA3; Thu, 25 Sep 2003 09:20:23 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by carver.gumbysoft.com (Postfix) with ESMTP id A3E1F72DA2; Thu, 25 Sep 2003 09:20:23 -0700 (PDT) Date: Thu, 25 Sep 2003 09:20:23 -0700 (PDT) From: Doug White To: Brian Behlendorf In-Reply-To: <20030923102845.I10424@fez.hyperreal.org> Message-ID: <20030925091757.N8717@carver.gumbysoft.com> References: <20030922120422.W8800@fez.hyperreal.org> <20030923091649.F86981@carver.gumbysoft.com> <20030923102845.I10424@fez.hyperreal.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: stable@freebsd.org Subject: Re: tuning parameters for parallel access to umass devices? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Sep 2003 16:20:27 -0000 On Tue, 23 Sep 2003, Brian Behlendorf wrote: > > On the volume being copied to, or another volume? > > On the volume being copied to (or from) - that is, while moving a big file > to/from such a device, doing an 'ls' or other operations on that device > are delayed. Well with the copy, its consuming all the available b/w to the device. Not much we can do about that without hurting I/O performance. > > > da2: 650KB/s transfers > > > > Don't forget that this isn't much faster than a floppy disk, and flash I/O > > is pretty slow anyway. > > Granted. This is do a hard drive that can definitely handle it - mounting > the same drive (Maxtor 5000XT) over firewire works brilliantly - the > full 50MB/s transfer speed, and parallel operations are fine. I just > don't have fw everywhere. Well duh ... firewire is 400Mbit, USB is 10Mbit :-) Not likely that thi sis an easy fix. It'd involve redoing the way I/O is scheduled to a device (*_strategy). -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org