From: Dan Aloni <da-x@monatomic.org>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: Some NCQ numbers...
Date: Wed, 4 Jul 2007 19:44:26 +0300 [thread overview]
Message-ID: <20070704164426.GA8061@localdomain> (raw)
In-Reply-To: <468BC81F.7090102@msgid.tls.msk.ru>
On Wed, Jul 04, 2007 at 08:17:35PM +0400, Michael Tokarev wrote:
> Dan Aloni wrote:
> > On Thu, Jun 28, 2007 at 02:51:58PM +0400, Michael Tokarev wrote:
> >> [..]
> >> Test machine was using MPTSAS driver for the following card:
> >> SCSI storage controller: LSI Logic / Symbios Logic SAS1064E PCI-Express Fusion-MPT SAS (rev 02)
> >>
> >> Pretty similar results were obtained on an AHCI controller:
> >> SATA controller: Intel Corporation 82801GR/GH (ICH7 Family) Serial ATA Storage Controller AHCI (rev 01)
> >> on another machines.
> >
> > Are you sure that NCQ was enabled between the controller and drive?
> > Did you verify this? I know about some versions that disable NCQ
> > support internally in their firmware (something to do with bugs in
> > error handling).
>
> The next obvious question is: how to check/verify this?
On the lowest level, it's possible using a protocol analyzer. If you
don't have one, you need to be familiar with the controller's driver
or its firmware. If the driver is based on libata, I think it's
possible to get this information easier. Otherwise, such as in the
case of mptsas, it can be completely hidden by the firmware.
--
Dan Aloni
XIV LTD, http://www.xivstorage.com
da-x (at) monatomic.org, dan (at) xiv.co.il
prev parent reply other threads:[~2007-07-04 16:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-28 10:51 Some NCQ numbers Michael Tokarev
2007-06-28 11:01 ` Michael Tokarev
2007-07-03 8:19 ` Tejun Heo
2007-07-03 20:29 ` Michael Tokarev
2007-07-04 1:19 ` Tejun Heo
2007-07-04 9:43 ` Michael Tokarev
2007-07-04 10:22 ` Justin Piszcz
2007-07-04 10:33 ` Justin Piszcz
2007-07-05 19:00 ` Bill Davidsen
2007-07-09 11:07 ` Justin Piszcz
2007-07-09 12:26 ` Jens Axboe
2007-07-05 19:22 ` Bill Davidsen
2007-07-04 14:40 ` James Bottomley
2007-07-09 12:26 ` Jens Axboe
2007-07-04 15:44 ` Dan Aloni
2007-07-04 16:17 ` Michael Tokarev
2007-07-04 16:44 ` Dan Aloni [this message]
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