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Date: Fri, 21 Aug 2009 14:22:25 +0200
From: Sascha Hauer <s.hauer@pengutronix.de>
To: Magnus Lilja <lilja.magnus@gmail.com>
Subject: Re: MXC nand controller performance
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On Thu, Aug 20, 2009 at 10:10:27PM +0200, Magnus Lilja wrote:
> Hi Sascha,
> 
> 2009/8/20 Sascha Hauer <s.hauer@pengutronix.de>:
> > Hi,
> >
> > Hi recently found out that on my i.MX27 board the mxc nand controller
> > performance nearly doubles when I disable interrupts. Can anybody
> > confirm this behaviour, possibly on other i.MXs?
> > I'm trying to figure out what to do. We could disable interrupts
> > completely in which case the driver would become simpler. Maybe using
> > polling mode has other impacts on other workloads, so maybe we want to
> > add a flag to platform_data instead of disabling interrupts completely.
> 
> A flag sounds like a good idea.
> 
> > You can use the following patch to disable interrupts. It is not meant
> > for inclusion in this form of course.
> 
> I can give it a try on i.MX31, how do you measure the performance?

I did a 'time cat /dev/mtdblockx > /dev/null' and looked at the time
needed to mount an ubifs. I haven't done any write tests though.

Sascha


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