From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: remove ixp2000 platform
Date: Wed, 7 Mar 2012 09:14:09 +0000 [thread overview]
Message-ID: <20120307091409.GL17370@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <CACRpkdYQpnSMVWUizEYHTjx_AK5Ai7dos0SBd208Wf5ZJLdrCw@mail.gmail.com>
On Wed, Mar 07, 2012 at 09:40:31AM +0100, Linus Walleij wrote:
> Network equipment seems to like using BE.
>
> I have some vague idea that this is beacuse IP packets are big
> endian, and thus you can process them quickly by just casting fields
> to e.g. u32 pointers and read them.
>
> I don't know if this is true, but seems to much of a correlation to
> be pure coincidence. Thus a pretty interesting subject in
> embedded ARM not used for tablets/mobile/generic computing
> kind of stuff.
ISTR Nicolas explained this to me as being an established thing in the
comms sector. They expect BE and only understand BE.
I did point out that you end up with many more endian conversions by
going to BE, mainly because PCI is LE and all your PCI accesses have
to be endian-swapped. So in terms of bandwidth, I'd expect an ARM
PCI platform running in BE mode to have worse throughput than a LE
PCI platform.
But... if BE allows the comms people to keep their warm fuzzy feeling
who are we to argue.
next prev parent reply other threads:[~2012-03-07 9:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1330450426-14639-1-git-send-email-robherring2@gmail.com>
2012-02-28 19:45 ` [PATCH] ARM: remove ixp2000 platform Arnd Bergmann
2012-03-06 1:41 ` Nicolas Pitre
2012-03-06 2:44 ` Rob Herring
2012-03-06 9:16 ` Russell King - ARM Linux
2012-03-06 14:11 ` Arnd Bergmann
2012-03-06 16:51 ` Nicolas Pitre
2012-03-06 17:10 ` Arnd Bergmann
2012-03-06 17:38 ` Richard Cochran
2012-03-07 8:40 ` Linus Walleij
2012-03-07 9:14 ` Russell King - ARM Linux [this message]
2012-03-07 11:54 ` Greg Ungerer
2012-03-11 12:31 ` Krzysztof Halasa
2012-03-11 23:48 ` Greg Ungerer
2012-03-13 21:15 ` Krzysztof Halasa
2012-03-07 17:09 ` Imre Kaloz
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