From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jay Strauss Subject: Re: Raid 1 install revealed poor HD performance (I think) Date: Thu, 19 May 2005 13:40:22 -0500 Message-ID: <428CDD96.2070006@heyjay.com> References: <428A09A3.9000802@heyjay.com> <428A81FB.1070201@home.se> <428CB19B.8010402@heyjay.com> <428CBB4A.8080900@h3c.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <428CBB4A.8080900@h3c.com> Sender: linux-raid-owner@vger.kernel.org To: Mike Hardy Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Mike Hardy wrote: > That's more like what we were expecting! > > I can't tell you why its like that or how, but this *is* the typical > problem with IDE. Most likely the chipset is being detected incorrectly, > or its being detected correctly but there is some errata that's > disabling dma, or maybe dma is experimental for the card. > > Places to look for information are in the dmesg for the sis chipset's > detection diagnostics, then on the internet as a google for your sis > chipset number then "linux dma" maybe. You may end up with some ide > things on your kernel command line (via grub or lilo) > > I'll reiterate something I said previously though, other than > write-caching (which is potentially dangerous) none of the other hdparm > or IDE settings are really going to give you that much of a boost unless > your workload is specifically tunable. They're all just little minor > twiddles you can do - nothing even close to the difference between > having DMA or not. So I'd just focus on enabling DMA. The other stuff is > all uninteresting compared to it. > > -Mike > Thanks for the reply Mike. After some Googling and looking at my kernel config file, it seems that SIS support is a module, like so: CONFIG_BLK_DEV_SIS5513=m I found this link but can't find any of the files that it references http://kerneltrap.org/comment/reply/4925/129324 I'm not sure if having CONFIG_BLK_DEV_SIS5513 as a module has anything to do with this. I can't get to my box right now, because out of curiosity I did hdparm -D 0 /dev/hda and ran the dd test, I think it crashed the box. The box is in my basement at home, so I'll have to wait until tonight. Jay