From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: ahci problems with sata disk. Date: Mon, 15 Jan 2007 22:50:56 +0900 Message-ID: <45AB86C0.2020507@gmail.com> References: <1168785128.7865.13.camel@duo> <45AB45B2.2080602@gmail.com> <1168859112.6980.8.camel@duo> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from an-out-0708.google.com ([209.85.132.242]:54212 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932317AbXAONvJ (ORCPT ); Mon, 15 Jan 2007 08:51:09 -0500 Received: by an-out-0708.google.com with SMTP id b33so793780ana for ; Mon, 15 Jan 2007 05:51:09 -0800 (PST) In-Reply-To: <1168859112.6980.8.camel@duo> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: kenneth johansson Cc: linux-ide@vger.kernel.org kenneth johansson wrote: > On Mon, 2007-01-15 at 18:13 +0900, Tejun Heo wrote: >> kenneth johansson wrote: >>> I changed my bios setting for SATA from IDE to AHCI. >>> >>> This resulted in some "interesting" read throughput. >>> >>> plots can be found at http://kenjo.org/~ken/sata/ >>> The plots was done on a live disk so some noise is expected but in the >>> ahci mode the throughput get stuck at 17 MB way to much. >> It's probably not an ahci problem but more of NCQ implementation problem >> in the drive firmware. Please report the result of 'hdparm -I /dev/sdX' >> and try adjust queue depth and see what happens. >> >> http://linux-ata.org/faq.html >> > > It was, when I turn of NCQ with "echo 1 >> /sys/block/sda/device/queue_depth" I get the same performance as when > the BIOS is set to IDE. Can you play with queue depth a bit? e.g. Benchmark queue depth of 4, 8 and 16. > I though that NCQ was intended to increase performance ?? Supposedly. > also the disk is a Westen Digital raptor and it's probably the most > benchmarked drive one could get so I was not expecting a problem with > the drive. Most benchmarked doesn't make the firmware any better, it seems. The raptor Alan talked about, reportedly, locks up after hours of NCQ load too. -- tejun