From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: libata sata_via unusual behaviour Date: Thu, 1 May 2008 19:58:23 +0100 Message-ID: <20080501195823.79786815@core> References: <3bbeafe90805011018o28f46794h369242ccb02b7ced@mail.gmail.com> <3bbeafe90805011158n5b45283awd43a7a534ba11456@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:50507 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1764345AbYEATGu (ORCPT ); Thu, 1 May 2008 15:06:50 -0400 In-Reply-To: <3bbeafe90805011158n5b45283awd43a7a534ba11456@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Paolo Cc: jgarzik@pobox.com, linux-ide@vger.kernel.org On Thu, 1 May 2008 20:58:37 +0200 Paolo wrote: > Hello! > > It seems that me and many others are experiencing poor sata performances > in the last months, probably with 2.6.20+ kernels. > > an example of these problems is here: > > http://ubuntuforums.org/showthread.php?p=4845777 > > unfortunately it seems that sata subsystem on linux is little to none > tweakable It doesn't normally need tweaking, and the hdparm numbers show that it is working correctly in the example you give. There may be problems higher up the stack but the ATA layer appears to be doing just fine. Perhaps the Ubuntu engineers could be persuaded to profile their problem systems and identify what is causing the slow down - LVM certain has been problematic for some setups if LVM is in use. Alan