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From: Mark Lord <kernel@teksavvy.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	"Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]"
	<asamymuthupa@micron.com>,
	linux-ide@vger.kernel.org
Subject: Re: New driver mtipx2xx submission
Date: Tue, 03 May 2011 11:02:31 -0400	[thread overview]
Message-ID: <4DC01907.50009@teksavvy.com> (raw)
In-Reply-To: <x49oc3lndyu.fsf@segfault.boston.devel.redhat.com>

On 11-05-02 02:40 PM, Jeff Moyer wrote:
..
> Given the highly parallel nature of these parts, I wouldn't be surprised
> if the ahci queue depth of 31 is one of the main bottlenecks.  Can you
> think of a way to extend the ahci driver in this manner to accommodate
> devices like this one?
..

I imagine that another performance drain might be libata's lack of
support for host controller queues --> a hardware queuing layer that
exists between the host and the drive's own queuing mechanism.

Most modern ATA/SATA chipsets have something of that nature.
These are designed to eliminate the activity-gaps that happen between
when a drive finishes a command, and when the host interrupt -> BH -> whatever
gets around to submitting a new command.

With commands already batched up in a hardware host queue, the controller
takes care of that part, keeping the drive active more of the time,
increasing IOPS.

Cheers

  parent reply	other threads:[~2011-05-03 15:02 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-28 15:53 New driver mtipx2xx submission Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]
2011-04-28 22:06 ` Alan Cox
2011-05-02 12:40   ` Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]
2011-05-02 17:42     ` Alan Cox
2011-05-03 20:07       ` [PATCH 0/3] " Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]
2011-05-11 17:40       ` Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]
2011-05-11 19:20         ` Alan Cox
2011-05-21  2:26           ` Asai Thambi S P
2011-05-25 14:36             ` Jeff Moyer
     [not found]               ` <22A973199D2C2F46933448F6E7990A300239EA77@ntxboimbx31.micron.com>
2011-06-01 19:51                 ` Jeff Moyer
2011-06-01 20:21                   ` Alan Cox
2011-06-15  1:29                     ` Asai Thambi S P
2011-06-15 14:43                       ` Jeff Moyer
2011-06-27 23:38                         ` Asai Thambi Samymuthu Pattrayasamy (asamymuthupa) [CONTRACTOR]
2011-06-28 15:18                           ` Jeff Moyer
2011-06-28 15:31                             ` Alan Cox
2011-06-28 15:38                               ` Jeff Moyer
2011-07-06 21:43                                 ` Asai Thambi S P
2011-07-07  7:37                                   ` Alan Cox
2011-07-26 10:46                                   ` Alan Cox
2011-07-26 11:44                                     ` Christoph Hellwig
2011-07-26 11:49                                       ` Alan Cox
2011-07-26 18:50                                       ` Jeff Garzik
2011-07-29 18:13                                     ` Asai Thambi S P
2011-08-11 18:36                                     ` Asai Thambi S P
2011-07-06 21:39                             ` Asai Thambi S P
2011-06-02  1:21                   ` David Dillow
2011-06-15  1:33                     ` Asai Thambi S P
2011-06-15  3:12                       ` David Dillow
2011-05-02 18:40   ` Jeff Moyer
2011-05-02 18:52     ` Alan Cox
2011-05-03 15:04       ` Mark Lord
2011-05-03 15:07         ` Alan Cox
2011-05-03 15:08           ` Mark Lord
2011-05-03 15:02     ` Mark Lord [this message]
2011-05-12 14:39       ` Jeff Garzik
  -- strict thread matches above, loose matches on Subject: below --
2011-05-03 11:09 Jordan_Hargrave

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