From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758491AbYELLn4 (ORCPT ); Mon, 12 May 2008 07:43:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751685AbYELLno (ORCPT ); Mon, 12 May 2008 07:43:44 -0400 Received: from relay1.sgi.com ([192.48.171.29]:59176 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751460AbYELLnn (ORCPT ); Mon, 12 May 2008 07:43:43 -0400 Date: Mon, 12 May 2008 21:43:25 +1000 From: David Chinner To: Jeremy Higdon Cc: Andrew Morton , David Chinner , lkml , linux-scsi@vger.kernel.org, Jens Axboe , jes@sgi.com Subject: Re: [PATCH] drivers/scsi/qla1280.c; was Re: Buffered I/O to block device very slow and other SCSI issues... Message-ID: <20080512114325.GI155679365@sgi.com> References: <20080319231654.GA103321673@sgi.com> <20080320010807.GA27620@sgi.com> <20080320032010.e640c52a.akpm@linux-foundation.org> <20080512061703.GC41683@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080512061703.GC41683@sgi.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 11, 2008 at 11:17:03PM -0700, Jeremy Higdon wrote: > On Thu, Mar 20, 2008 at 03:20:10AM -0700, Andrew Morton wrote: > > > > I also suspect that CTQ has not been set up correctly on this > > > > kernel, because: > > > > > > > > $ cat /sys/block/sdb/device/queue_depth > > > > 3 > > > > $ ls -l /sys/block/sdb/device/queue_depth > > > > -r--r--r-- 1 root root 0 Mar 20 09:59 /sys/block/sdb/device/queue_depth > > > > $ > > > > > > > > It appears to be hard coded to 3 and can't be changed.... > > > > > > That's a bug in the qla1280 driver. I thought that had gotten fixed. > > > It's looking at the wrong mailbox register after setting device parameters. > > > > Was there a patch anywhere? > > Promised patch... .... > After the fix, I found that my disks were getting a queue depth of > 255, which is far too many. Most SCSI disks are limited to 32 or > 64. In any case, there's no point, queueing up a bunch of commands > to the adapter that will just result in queue full or starve other > targets from being issued commands due to running out of internal > memory. So I dropped default queue depth to 32 (from which 1 is > subtracted elsewhere, giving net of 31). > > I tested with a Seagate ST336753LC, and results look good, so > I'm satisfied with this patch. > > Signed-off-by: Jeremy Higdon Works fine here. Tested-by: Dave Chinner Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group