From mboxrd@z Thu Jan 1 00:00:00 1970 From: "kyle" Subject: Re: ahci slow transfer rate with kernel 2.6.23-2.6.25 Date: Mon, 28 Apr 2008 22:45:20 +0800 Message-ID: <003901c8a93e$7b4e88b0$0a01a8c0@kylecea1512a3f> References: <9359bbd70804280211ta587f87sff83dba5f7974796@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: "Sergey A. Sukiyazov" , kyle List-Id: linux-raid.ids Ok, I'll try set queue_depth to 1 to see if there's any improvement. btw, the same disk connected to sil3132 controller has no problem at all with queue_depth = 31, I got over 100MB/s for hdparm, dd, etc test with ST3500320AS + sil3132. So I assume the problem would be ahci. Thanks a lot. ----- Original Message ----- From: Sergey A. Sukiyazov To: kylewong@southa.com Sent: Monday, April 28, 2008 5:11 PM Subject: Re: ahci slow transfer rate with kernel 2.6.23-2.6.25 Hi I have some problem. Try set queue_depth in "1" for disks, it disables NCQ and the transfer rate has returned to 100MB/S. It's ST3500320AS problem with NCQ implementation (I think :-)) for i in sda sdb sdd sdf ; do echo "1" > /sys/block/${i}/device/queue_depth done See also: http://bugzilla.kernel.org/show_bug.cgi?id=8327 -- Best regards Sergey A. Sukiyazov http://corwin.rostovlinux.ru/