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From: Robert Hancock <hancockr@shaw.ca>
To: Daniel Drake <dsd@gentoo.org>
Cc: linux-kernel@vger.kernel.org, davem@davemloft.net
Subject: Re: [RFC] Documentation about unaligned memory access
Date: Thu, 22 Nov 2007 19:24:12 -0600	[thread overview]
Message-ID: <47462BBC.2000206@shaw.ca> (raw)
In-Reply-To: <fa.U+CIv4JClOmn6KppLkEOSk7RW0Y@ifi.uio.no>

Daniel Drake wrote:
> Being spoilt by the luxuries of i386/x86_64 I've never really had a good
> grasp on unaligned memory access problems on other architectures and decided
> it was time to figure it out. As a result I've written this documentation
> which I plan to submit for inclusion as
> Documentation/unaligned_memory_access.txt
> 
> Before I do so, any comments on the following?

...

> You may be wondering why you have never seen these problems on your own
> architecture. Some architectures (such as i386 and x86_64) do not have this
> limitation, but nevertheless it is important for you to write portable code
> that works everywhere.

Also, x86 doesn't prohibit unaligned accesses, but I believe they have a 
significant performance cost and are best avoided where possible.

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/


       reply	other threads:[~2007-11-23  1:25 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.U+CIv4JClOmn6KppLkEOSk7RW0Y@ifi.uio.no>
2007-11-23  1:24 ` Robert Hancock [this message]
2007-11-23  2:07   ` [RFC] Documentation about unaligned memory access Andi Kleen
2007-11-23  0:15 Daniel Drake
2007-11-23  0:27 ` Avuton Olrich
2007-11-23  1:29 ` Alan Cox
2007-11-23  3:04   ` Kyle Moffett
2007-11-23  6:18   ` dean gaudet
2007-11-23  9:46     ` Arne Georg Gleditsch
2007-11-26 14:50       ` dean gaudet
2007-11-23  1:29 ` David Miller
2007-11-23 10:06 ` Jan Engelhardt
2007-11-23 11:43 ` Heikki Orsila
2007-11-25 11:16   ` Geert Uytterhoeven
2007-11-25 11:24     ` Heikki Orsila
2007-11-26  0:48       ` Alan Cox
2007-11-26 17:12   ` Ben Dooks
2007-11-27  7:51   ` Kumar Gala
2007-11-23 22:02 ` Vadim Lobanov
2007-11-23 22:52 ` Dmitri Vorobiev
2007-11-24 13:34 ` Pierre Ossman
2007-11-24 15:50   ` Luciano Rocha
2007-11-24 16:19     ` Pierre Ossman
2007-11-24 17:22       ` Luciano Rocha
2007-11-24 17:35         ` Pierre Ossman
2007-11-24 18:28           ` Luciano Rocha
2007-11-24 17:53         ` Haavard Skinnemoen
2007-11-25  8:27 ` Denys Vlasenko
2007-11-25 14:13 ` Olaf Titz
2007-11-26  9:14 ` DM
2007-11-26 14:47 ` Johannes Berg
2007-11-27  0:40   ` Arnaldo Carvalho de Melo
2007-11-26 14:51 ` Johannes Berg
2007-11-30  8:18 ` Jörn Engel

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