From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1766696AbXDEQMB (ORCPT ); Thu, 5 Apr 2007 12:12:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1767131AbXDEQMB (ORCPT ); Thu, 5 Apr 2007 12:12:01 -0400 Received: from ottawa-hs-64-26-128-89.s-ip.magma.ca ([64.26.128.89]:3333 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1766696AbXDEQMA (ORCPT ); Thu, 5 Apr 2007 12:12:00 -0400 Message-ID: <46151FCD.6000700@rtr.ca> Date: Thu, 05 Apr 2007 12:11:57 -0400 From: Mark Lord User-Agent: Thunderbird 1.5.0.10 (X11/20070221) MIME-Version: 1.0 To: Phillip Susi Cc: Chris Snook , Paa Paa , linux-kernel@vger.kernel.org Subject: Re: Lower HD transfer rate with NCQ enabled? References: <46128175.2090506@redhat.com> <4612852C.2030801@rtr.ca> <4612A854.1070702@cfl.rr.com> <4613C612.5040600@rtr.ca> <4615160A.4090506@cfl.rr.com> In-Reply-To: <4615160A.4090506@cfl.rr.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Phillip Susi wrote: > Mark Lord wrote: >> This is mostly a problem with the WD Raptor drive, and some other WD >> drives. >> I have not yet encountered/noticed the problem with other brands. > > Sounds like this is a serious bug in the WD firmware. For personal systems, yes. For servers, probably not a bug. Disabling readahead means faster execution queued commands, since it doesn't have to "linger" and do unwanted read-ahead. So this bug is a "feature" for random access servers. And a big nuisance for everything else. Cheers