From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 6/8] libata: adjust speed down rules Date: Wed, 28 Nov 2007 08:07:10 +0900 Message-ID: <474CA31E.4000508@gmail.com> References: <11961593392491-git-send-email-htejun@gmail.com> <11961593403415-git-send-email-htejun@gmail.com> <474C9B10.4060500@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ag-out-0708.google.com ([72.14.246.249]:47720 "EHLO ag-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759543AbXK0XHS (ORCPT ); Tue, 27 Nov 2007 18:07:18 -0500 Received: by ag-out-0708.google.com with SMTP id 35so1533193aga for ; Tue, 27 Nov 2007 15:07:17 -0800 (PST) In-Reply-To: <474C9B10.4060500@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: jeff@garzik.org, linux-ide@vger.kernel.org, bzolnier@gmail.com Hello, Mark. Mark Lord wrote: > Tejun Heo wrote: >> Speed down rules were too conservative. Adjust them a bit. >> >> * More than 10 timeouts can't happen in 5 minutes as command timeout >> is 30secs. Lower the limit for rule #1 to 6. >> >> * 10 timeouts is too high for rule #3 too. Lower it to 6. >> >> * SATAPI can benefit from falling back to PIO too. Allow SATAPI >> devices to fall back to PIO. > .. > > Mmmm... I see two remaining problems with this: > > -- bad sectors (media errors) will cause inappropriate speed-downs. No. Media error is category 0 error which doesn't affect speed down at all. > -- deliberate (or otherwise) errors via SG_IO will cause inappropriate > speed-downs. No, only device errors issued via block layer are considered for speed down (ATA_QCFLAG_IO). SG_IO commands will never trigger speed down unless the error is HSM or timeout. Thanks. -- tejun