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From: msalter@redhat.com (Mark Salter)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP
Date: Wed, 31 Aug 2011 09:43:33 -0400	[thread overview]
Message-ID: <1314798215.2344.76.camel@deneb.redhat.com> (raw)
In-Reply-To: <20110831084922.GA8777@e102144-lin.cambridge.arm.com>

On Wed, 2011-08-31 at 09:49 +0100, Will Deacon wrote:
> On Wed, Aug 31, 2011 at 01:23:47AM +0100, Chen Peter-B29397 wrote:
> > One question: why this write buffer issue did not happen at UP ARM V7 platform, whose dma buffer
> > also uncache, but bufferable?
> 
> Which CPU was on this platform?

Using a 3.1.0-rc4+ kernel on a Pandaboard, and running 'hdparm -t' on a
usb disk drive, I see ~5.8MB/s read speed. Same kernel, but passing
nosmp on the commandline, I see 20.3MB/s.

Can someone explain why nosmp would make such a difference?

--Mark

  parent reply	other threads:[~2011-08-31 13:43 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-30 16:03 [PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP ming.lei at canonical.com
2011-08-30 16:15 ` Alan Stern
2011-08-30 16:38 ` Mark Salter
2011-08-30 17:15   ` Alan Stern
2011-08-30 18:45     ` Mark Salter
2011-08-30 17:26   ` Will Deacon
2011-08-30 17:48     ` Greg KH
2011-08-30 17:54       ` Will Deacon
2011-08-31  0:23         ` Chen Peter-B29397
2011-08-31  8:49           ` Will Deacon
2011-08-31 12:33             ` Chen Peter-B29397
2011-08-31 13:43             ` Mark Salter [this message]
2011-08-31 15:21               ` Will Deacon
2011-08-31 15:27                 ` Mark Salter
2011-08-31 16:12                   ` Marc Zyngier
2011-08-31 16:55                     ` Marc Dietrich
2011-09-01 10:34                       ` Marc Zyngier
2011-09-01 11:13                         ` Marc Dietich
2011-09-01 19:08                           ` Stephen Warren
2011-09-02  9:50                             ` Marc Zyngier
2011-09-02 17:07                               ` Stephen Warren
2011-09-02 11:13                             ` Marc Dietich
2011-08-31 17:46                 ` Nicolas Pitre
2011-08-31 17:51                   ` Will Deacon
2011-08-31 18:19                     ` Rob Herring
2011-08-31 18:35                       ` Mark Salter
2011-08-31 18:49                         ` Rob Herring
2011-08-31 18:58                           ` Mark Salter
2011-08-31 19:35                       ` Will Deacon
2011-09-08 22:41                         ` Mark Salter
2011-10-31  6:49                           ` Pandita, Vikram
2011-08-31  0:56         ` Ming Lei

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