From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [patch 6/7] ps3: ROM Storage Driver
Date: Tue, 29 May 2007 21:31:59 +1000
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To: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: Christoph Hellwig <hch@lst.de>, linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org

On Tue, 2007-05-29 at 13:11 +0200, Geert Uytterhoeven wrote:
> > This looks very inefficient.  Just set sg_tablesize of your driver
> > to 1 to avoid getting mutiple segments.
> 
> The disadvantage of setting sg_tablesize = 1 is that the driver will
> get small
> requests (PAGE_SIZE) most of the time, which is very bad for
> performance.

And the joke is that not only the HW can do scatter & gather but you
also have an iommu ...

Ben.