ARMv7

Hi,

(Please note that the following comments are just thoughts and i may be wrong. You’re free to correct me)

-So whats this ARMv7 i keep talking about?
-Well, its just the latest version of the ARM processor.
-What’s so important about it?
-It contains some CPU instructions that the previous ARM CPUs don’t have. Those instructions provide a really good performance and more power efficiency on which the previous CPUs(ARMv5,v6) can’t provide.
-What are ARMv7 processors going to be used for?
-Mainly smartbooks and nettops.

Almost all the bigger distros have ARM support for a long time ago. Debian was probably the first distribution to offer support for it, back in 2001 or 2002. Gentoo started on 2003-2004. Ubuntu, for example, started working on its ARM support since last year.

There’s a problem with binary distros, though. For example, Debian and Ubuntu support i386. For doing that, they have to build everything to work for i386, meaning that all the performance improvement you could get using i686-exclusive CPU instructions is lost. I’m no expert and I’m not proving anything, i’m just using an example. As I said before, ARMv7 provides some cpu instructions that with Debian or Ubuntu won’t be used, since they build to the lower of the CPUs available. In the case of ARM EABI, that is armv4t(i think on Ubuntu the minimum was armv5te). I won’t say whether thats going to matter on the performance or not, as i can’t test it, but I’ve been told it does due to the following thing I’m going to explain:

The first release of Ubuntu “supporting” ARM was Jaunty. I wrote “supporting” because they only offered installation and support for a development board called “babbage”, which is a Freescale i.MX51-based Pegatron-built development board. Which at the time of the Jaunty release, it *wasn’t* available for purchase(it was a prototype), at least it wasn’t on its webpage.
Fortunately, all the users that had an ARMv5te processor could run Ubuntu on their boards, yet obviously with their own kernel, with no installer, and with no support from Ubuntu.

The next release of Ubuntu “supported” another prototype-not-public board, this time from Marvell, with the name “Dove”. And as of now, thats the boards they are supporting. Also, this release let the armv5te users with no upgrade, as Karmic(the release i’m talking about), is built with armv6+vfp as minimum requirement. That left out users of the Sheevaplug, which funnily enough, comes with Ubuntu. The next Ubuntu release will be Lucid, will only support armv7. So if anyone with a Nokia N800 was running Ubuntu on it, on the next release they’ll be alone in the dark as well.
By the way, Ubuntu doesn’t support the Beagleboard…I have no clue why.

Since we’re a source-based distribution, and we don’t depend on the minimum CPU, thats why we would like to have armv7 hardware capable of doing the kinds of build(like ubuntu are) we require. Unfortunately neither Marvell nor Freescale contacted us regarding ARMv7. Needless to say we also contacted them…
We’re also happy with just SSH access and non-networked storage of around 8GB.

This makes you kinda sad, as on Gentoo we don’t do this for profit, we only do it for our users, or at least thats what I do.

If anyone can or want to help us, you’re free to contact us at arm -at- gentoo.org.

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9 Responses to “ARMv7”

  1. Vittorio Says:

    that’s so sorry to hear 😦
    i hope that some donators step in

    btw aren’t debian and ubuntu targeted for i586?

    • armin762 Says:

      Nope, i486 to be correct, and thats because glibc-2.5(maybe? can’t remember exact version) dropped i386 support.

      Here:
      http://www.debian.org/releases/stable/i386/ch02s01.html.en

      It says:
      However, Debian GNU/Linux lenny will not run on 386 or earlier processors. Despite the architecture name “i386”, support for actual 80386 processors (and their clones) was dropped with the Sarge (r3.1) release of Debian[2]. (No version of Linux has ever supported the 286 or earlier chips in the series.) All i486 and later processors are still supported[3].

  2. Twinsen Says:

    Hi,
    Unfortunately I’m not able to donate a beagleboard, or any other armv7 based device, but I have one, and I run gentoo linux on it. It’s pretty cool, really! 🙂
    There are a few other guys who hack gentoo on these devices, check http://www.neuvoo.org.
    If I can help with any armv7 development (toolchain options, package testing, etc.) please let me know.

  3. Gentoo: Genesi Efika MX unboxing and first impressions. | Jeremy's Weblog Says:

    […] Gentoo Linux on it and help armin76 document the installation […]

  4. Matt Sealey Says:

    Hi Raul,

    Jeremy and yourself should have received your Efika MX sometime now.. so you have ARMv7 hardware 🙂

    Since Gentoo is source-based I do wonder if you can compile it with the hard float ABI. Maybe this gives some performance improvements (the difference between soft float ABI and hard float ABI is when floats or doubles are passed they are passed as pointers, stack or in integer registers for soft float ABI then reloaded into the FPU. In hard float ABI they’re passed in the FPU registers ready for use.. just like PowerPC). This allows the VFP unit to be used more efficiently.

    Granted, Gentoo for armv7 packages would not run – even if no armv7 instructions are used – on any other hardware since the ABI changes in a subtle way that breaks everything. The entire system would need to be bootstrapped from the ground up using the hard float ABI. However it is guaranteed to give the very best performance 🙂

    • armin762 Says:

      Hi Matt,

      Jeremy has it but I don’t yet, ETA is 10th of december :/

      Now that we have the hardware we are going to play with performance enhacements, that’s for sure. The problem until now is that almost all the ARMv5TE hardware had software FP, so it was a loss of time, but now its not.

      Thanks for everything

  5. ARMv7 stages available « Armin76's Blog Says:

    […] Related post: https://armin762.wordpress.com/2009/11/25/armv7/ […]

  6. ARM status @ Gentoo « Armin76's Blog Says:

    […] I commented in other blogpost, we we’re looking for ARMv7 hardware(and we still are, i’m not the only one on the ARM team), to allow us building of stages and […]

  7. ARMv7 SoCs: Freescale i.MX51 Babbage, TI OMAP3, Marvell Dove/Armada, Qualcomm Snapdragon… « Armin76's Blog Says:

    […] ARMv7 SoCs: Freescale i.MX51 Babbage, TI OMAP3, Marvell Dove/Armada, Qualcomm Snapdragon… By armin762 This is a continuation of the ARMv7 post i wrote last year. […]

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