From owner-freebsd-hackers@FreeBSD.ORG Sat Jul 1 15:31:03 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EFCE216A407 for ; Sat, 1 Jul 2006 15:31:03 +0000 (UTC) (envelope-from hselasky@c2i.net) Received: from swip.net (mailfe10.swip.net [212.247.155.33]) by mx1.FreeBSD.org (Postfix) with ESMTP id BA99344245 for ; Sat, 1 Jul 2006 15:07:12 +0000 (GMT) (envelope-from hselasky@c2i.net) X-T2-Posting-ID: gvlK0tOCzrqh9CPROFOFPw== X-Cloudmark-Score: 0.000000 [] Received: from mp-216-87-87.daxnet.no ([193.216.87.87] verified) by mailfe10.swip.net (CommuniGate Pro SMTP 5.0.8) with ESMTP id 56686289; Sat, 01 Jul 2006 17:07:10 +0200 From: Hans Petter Selasky To: thierry@herbelot.com Date: Sat, 1 Jul 2006 17:07:16 +0200 User-Agent: KMail/1.7 References: <200605271102.19799.hselasky@c2i.net> <200607011531.11061.hselasky@c2i.net> <200607011624.08249.thierry@herbelot.com> In-Reply-To: <200607011624.08249.thierry@herbelot.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200607011707.17055.hselasky@c2i.net> Cc: freebsd-hackers@freebsd.org Subject: Re: High-speed transfers X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 Jul 2006 15:31:04 -0000 On Saturday 01 July 2006 16:24, Thierry Herbelot wrote: > Le Saturday 1 July 2006 15:31, Hans Petter Selasky a =E9crit : > > Yes, but don't forget high-speed USB transfers. They require larger > > buffers. For example 1024 bytes for ULPT is too little. The interrupt > > rate will be so high, that it is unrealistic to transfer 20MB/s using > > 1024 byte interrupts. My rewritten ULPT now uses "2*(1<<17)" buffers. > > Hello, > > I wonder what kind of speed you are getting=20 It depends much on the equipment you are using. For example I have a Brothe= r=20 USB 2.0, Laser Printer, postscript compatible, and if I were to guess, it=20 eats something like 1MB/s. On the other hand I tested with an external USB= =20 2.0, 2.5" IDE adapter, and it transfers around 20MB/s. > : I would like to see improvements for reads (and writes) on=20 > standard endpoints, without having to resort to writing specific=20 > drivers (using ugen on the standard FreeBSD USB stack). > > One goal would be to achieve something like 25 to 30 Mbytes/s, sustained, > (finally getting to some interesting fraction of the peak USB2 data rate). I don't think that will be a problem, as long as you use large enough buffe= rs.=20 A buffer of 1/50 th of the transfer rate should suffice, from my experience. =2D-HPS