From owner-freebsd-stable@FreeBSD.ORG Fri Feb 8 17:37:09 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B678E16A421 for ; Fri, 8 Feb 2008 17:37:09 +0000 (UTC) (envelope-from pieter@degoeje.nl) Received: from smtp.utwente.nl (unknown [IPv6:2001:610:1908:1000:204:23ff:feb7:ef56]) by mx1.freebsd.org (Postfix) with ESMTP id 2F4F513C459 for ; Fri, 8 Feb 2008 17:37:09 +0000 (UTC) (envelope-from pieter@degoeje.nl) Received: from lux.student.utwente.nl (lux.student.utwente.nl [130.89.170.81]) by smtp.utwente.nl (8.12.10/SuSE Linux 0.7) with ESMTP id m18Hb1nr024180; Fri, 8 Feb 2008 18:37:02 +0100 From: Pieter de Goeje To: freebsd-stable@freebsd.org Date: Fri, 8 Feb 2008 18:37:01 +0100 User-Agent: KMail/1.9.7 References: <47A9F835.1060200@bsdforen.de> <47AC7FF6.1020801@bsdforen.de> <1202491071.2126.42.camel@localhost> In-Reply-To: <1202491071.2126.42.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200802081837.01676.pieter@degoeje.nl> X-UTwente-MailScanner-Information: Scanned by MailScanner. Contact servicedesk@icts.utwente.nl for more information. X-UTwente-MailScanner: Found to be clean X-UTwente-MailScanner-From: pieter@degoeje.nl X-Spam-Status: No Cc: Tom Evans , Dominic Fandrey , "Carlos A. M. dos Santos" Subject: Re: RELENG_7: interrupt eating whole cpu core X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 08 Feb 2008 17:37:09 -0000 On Friday 08 February 2008, Tom Evans wrote: > On Fri, 2008-02-08 at 17:14 +0100, Dominic Fandrey wrote: > > Tom Evans wrote: > > > If I try to turn on DMA, I just get WDMA2, which just doesn't cut it: > > > > I think any DMA mode is fast enough to handle a DVD drive. There's just > > no necessity for more. > > WDMA is not UDMA. Any UDMA variant would be enough. WDMA2 provides a > maximum of 16MiB/s, which will frequently lead to buffer underruns > viewing a DVD. UDMA2 provides a maximum of 33MiB/s, which IS plenty. DVD video is encoded at max. ~7Mbit/sec, which is way below 16MB/sec. You should have no problems viewing dvds. > > > >> # atacontrol mode acd0 udma5 > > > > > > current mode = WDMA2 > > > > Same as for me. I'm satisfied with the speed of the drive. > > I'm rarely satisfied - I'm quite often not bothered enough to pursue :) > > Tom -- Pieter de Goeje