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From: Mark Lord <liml@rtr.ca>
To: Gwendal Grignou <gwendal@google.com>
Cc: Jeff Garzik <jeff@garzik.org>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Grant Grundler <grundler@google.com>,
	Jens Axboe <jens.axboe@oracle.com>,
	linux-ide@vger.kernel.org, htejun@gmail.com
Subject: Re: [PATCH 1/2] libata: switch to using block layer tagging support
Date: Thu, 21 May 2009 09:44:05 -0400	[thread overview]
Message-ID: <4A155AA5.3080704@rtr.ca> (raw)
In-Reply-To: <e7510f760905201242s3cb84154m6e9a5795fd2357c5@mail.gmail.com>

Gwendal Grignou wrote:
> Jeff, you're right, I made some mistakes:
> - Reading SiI3132 doc again, it only supports 32 command per port, so
> the tags must be share among all the drives behind the same port.
> But other chipset does support up to 128 commands per port.
> - Jens' patch is working when all disks support NCQ. Only when we have
> a mix of drives with or without NCQ we have a problem.
..

Along those lines, the newer Marvell chipsets support up to 128 commands
per host port.

I seem to recall that the Pacific Digital Qstor chip
can manage an insane number of commands -- something like
32 per device per PM port [eg. (15 * 32) in total per host port].

Seems to be a widespread kind of thing for non-legacy chipsets.
Someday we really ought to beef up libata to allow host-chipset queuing
of non-NCQ commands, too.

Cheers 

  parent reply	other threads:[~2009-05-21 13:44 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-20  6:59 [PATCH 0/2] libata: switch to block layer tagging Jens Axboe
2009-05-20  7:00 ` [PATCH 1/2] libata: switch to using block layer tagging support Jens Axboe
2009-05-20 11:53   ` Tejun Heo
2009-05-20 17:10   ` Grant Grundler
2009-05-20 18:08     ` Gwendal Grignou
2009-05-20 18:50       ` James Bottomley
2009-05-20 18:58         ` Jeff Garzik
2009-05-20 19:04           ` Jeff Garzik
2009-05-20 19:42             ` Gwendal Grignou
2009-05-20 19:47               ` Jeff Garzik
2009-05-21 13:44               ` Mark Lord [this message]
2009-05-21 17:27                 ` Jeff Garzik
2009-05-20 18:51       ` Jeff Garzik
2009-05-20 19:09     ` Jeff Garzik
2009-06-10 15:11   ` Jeff Garzik
2009-06-11  2:10     ` Tejun Heo
2009-05-20  7:01 ` [PATCH 2/2] block: add function for waiting for a specific free tag Jens Axboe
2009-05-20 11:55   ` Tejun Heo
2009-05-20 19:34     ` old-EH and SAS (was Re: [PATCH 2/2] block: add function for waiting for a specific free tag) Jeff Garzik
2009-05-21 16:34       ` Brian King
2009-05-20 17:28   ` [PATCH 2/2] block: add function for waiting for a specific free tag Grant Grundler
2009-05-20  7:53 ` [PATCH 0/2] libata: switch to block layer tagging Jeff Garzik
2009-05-20  7:57   ` Jens Axboe

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