From owner-freebsd-stable@FreeBSD.ORG Tue Feb 12 09:53:42 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 4D42616A469 for ; Tue, 12 Feb 2008 09:53:42 +0000 (UTC) (envelope-from kamikaze@bsdforen.de) Received: from mail.bsdforen.de (bsdforen.de [212.204.60.79]) by mx1.freebsd.org (Postfix) with ESMTP id EF91213C4F0 for ; Tue, 12 Feb 2008 09:53:41 +0000 (UTC) (envelope-from kamikaze@bsdforen.de) Received: from mobileKamikaze.norad (nat-wh-1.rz.uni-karlsruhe.de [129.13.72.169]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.bsdforen.de (Postfix) with ESMTP id 462F6405B16; Tue, 12 Feb 2008 10:53:40 +0100 (CET) Message-ID: <47B16CA3.5070700@bsdforen.de> Date: Tue, 12 Feb 2008 10:53:39 +0100 From: Dominic Fandrey User-Agent: Thunderbird 2.0.0.9 (X11/20080205) MIME-Version: 1.0 To: Tom Evans References: <47A9F835.1060200@bsdforen.de> <47AA0696.5020109@bsdforen.de> <7872AB6E-21DA-4E2D-93C0-D07CFA3A7E47@mac.com> <47AA0E3E.4020304@bsdforen.de> <47ABF66E.4040807@bsdforen.de> <1202485501.2126.34.camel@localhost> <47AC7FF6.1020801@bsdforen.de> <1202491071.2126.42.camel@localhost> <47ACA0E4.2030905@bsdforen.de> <1202808057.2126.45.camel@localhost> In-Reply-To: <1202808057.2126.45.camel@localhost> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "Carlos A. M. dos Santos" , freebsd-stable@freebsd.org 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: Tue, 12 Feb 2008 09:53:42 -0000 Tom Evans wrote: > On Fri, 2008-02-08 at 19:35 +0100, Dominic Fandrey wrote: >> 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. >> 16MB/s is exactly what is needed for 12x DVD access. I think this is the usual >> speed for a Notebook drive nowadays and it suffices for me. >> >>>>>> # 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 :) >> Well, if 12x speed is not enough for you, you have to use an external drive. >> This is not a driver issue. It's just what your drive supports. > > The chipset supports UDMA6, the drive supports UDMA6, I should be happy > with WDMA2 because 'thats what works'? Thanks for your 'help'. I'll > continue on here from myself. I don't know which drive you are using, but mine even only supports 8xDVD-reading so the highest transfer rate is 9.9606 MB/s. There's no way a faster mode would improve anything.