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Trim-Slice: Dual-Core ARM Tegra 2 Desktop

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  • #16
    Originally posted by gururise View Post
    Michael,

    Thank you for these recent great ARM reviews! Could you please include power consumption for these ARM systems in your tests? It can be as simple as measuring from the wall plug.

    Also, its very interesting that this Tegra 2 box beat out the Pandaboard with a "theoretically" better processor running at 20% higher speed with NEON extensions, and they managed this on an Ubuntu 11.04 distro with an older kernel.

    Trim-Slice must have backported some ARM optimizations from the newer kernels to achieve this. I'd really like to see a comparison of both the Pandaboard (omap) and Trim-Slice (tegra) running on the latest Linux 3.2 kernel. That would make for a very interesting comparison.
    There is an easy explanation.. in ubuntu 11.10 / 3.0 kernel, there isn't much power mgmt and 4460 is only running at a conservative ~700MHz (IIRC.. I don't have that kernel handy, but rule of thumb for cortex-a9 is that bogomips will be 2x clock speed). The boot loader just configures clocks with a conservative setting, and expects DVFS to take over once the kernel starts, but there is no DVFS enabled in that kernel.

    It does appear from benchmark results that none of the benchmarks are benefiting from NEON. That would give a significant advantage, even at lower clock speeds, for algorithms that can be vectorized. (I'm also not sure to what extent the x86 benchmarks benefit from MMX/SSE.. so I'm not quite sure if for an apples-to-apples comparison neon should be utilized)

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    • #17
      Originally posted by cynyr View Post
      Okay, I keep looking at these ARM boards off and on and keep asking myself what would I do with it.
      [*]File Server, no go not enough SATA ports or an expansion slot.
      Port multiplier may help. Even with a single port's bandwidth being split among multiple devices, you are still limited to the network speed.

      [*]HTPC, Not enough grunt to get 1080P or even 720P done.
      Virtually ALL ARM chips have dedicated video decoder hardware. These, in fact, would make ***EXCELLENT*** HTPCs for precisely this reason. You don't need a massive CPU for video decoding.

      No flash so not Hulu, or youtube. Running full linux, so no netflix.[*]Desktop for grandma/kids, no flash as it is arm + linux based, no way to play those cheep games from the bin at bestbuy.
      You don't have to use a "full linux".... Adobe has an Android/ARM version available, Google has a youtube application, netflix has an android version.

      Does the arm world have something like PCI-E or even PCI? How about a way to get more than 4 SATA ports and Dual GbE Lan that isn't via USB2.0?
      I don't think that there is any chance of this kind of device running up against server hardware any time soon. For now that will remain dominated by x86_64.

      Anyways, could someone explain to me what I would do with a Trim-Slice/Pandaboard ES? Looks fun to play with and maybe it would work nice for a kitchen/embeded computer, but I'm just not getting it.
      HTPC is probably the main use for now, as well as low power "light use" desktop systems.

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      • #18
        Originally posted by cynyr View Post
        Okay, I keep looking at these ARM boards off and on and keep asking myself what would I do with it.
        1. File Server, no go not enough SATA ports or an expansion slot.
        2. HTPC, Not enough grunt to get 1080P or even 720P done. No flash so not Hulu, or youtube. Running full linux, so no netflix.
        3. Desktop for grandma/kids, no flash as it is arm + linux based, no way to play those cheep games from the bin at bestbuy.

        Does the arm world have something like PCI-E or even PCI? How about a way to get more than 4 SATA ports and Dual GbE Lan that isn't via USB2.0?

        Anyways, could someone explain to me what I would do with a Trim-Slice/Pandaboard ES? Looks fun to play with and maybe it would work nice for a kitchen/embeded computer, but I'm just not getting it.
        one idea:
        http://rsalveti.wordpress.com/2012/0...ubuntu-linaro/

        or hopefully in near future:
        http://rsalveti.wordpress.com/2012/0...nd-next-steps/

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        • #19
          Originally posted by droidhacker View Post
          Port multiplier may help. Even with a single port's bandwidth being split among multiple devices, you are still limited to the network speed.
          This is true, right up until you want to rebuild a software raid array...


          Originally posted by droidhacker View Post
          Virtually ALL ARM chips have dedicated video decoder hardware. These, in fact, would make ***EXCELLENT*** HTPCs for precisely this reason. You don't need a massive CPU for video decoding.
          Very few of these seem to support high bit rate high profile high level h264 (think 25MB/sec 1080P high profile level 4.1 with 8.1 channel AAC audio or raw PCM), or anything else of equivalent quality. My Tegra based tablet doesn't really like my 480P high profile level 4.1, with 5.1 AAC DVD rips. Later this could become 4k2k 3D at even higher bitrates. Anyways, I'd like to not need to replace this for 5 years or so, so buying some extra power now would be a good idea.


          Originally posted by droidhacker View Post
          You don't have to use a "full linux".... Adobe has an Android/ARM version available, Google has a youtube application, netflix has an android version.
          Right, I could roll my own version of android, but that isn't really ideal for an HTPC as it would be hard to get a mythTV/XBMC/Boxee sort of experiance. It also would then leave out hulu for hulu plus.


          Originally posted by droidhacker View Post
          I don't think that there is any chance of this kind of device running up against server hardware any time soon. For now that will remain dominated by x86_64.


          HTPC is probably the main use for now, as well as low power "light use" desktop systems.
          I would love to get to an even lower power than the AMD E-350 server I'm building (~18W TDP for the board, we'll see if i can measure actual power consumption). It idles 95% of the day (seeding gentoo dvd isos mostly) and then gets used to send a video to my PS3, or desktop/laptop in the evenings. So it's not like it needs a pile of power.

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          • #20
            Originally posted by robclark View Post
            There is an easy explanation.. in ubuntu 11.10 / 3.0 kernel, there isn't much power mgmt and 4460 is only running at a conservative ~700MHz (IIRC.. I don't have that kernel handy, but rule of thumb for cortex-a9 is that bogomips will be 2x clock speed). The boot loader just configures clocks with a conservative setting, and expects DVFS to take over once the kernel starts, but there is no DVFS enabled in that kernel.
            Do release notes for ARM version of ubuntu 11.10 mention this fact in any way? This would clearly help to avoid a lot of confusion.

            It does appear from benchmark results that none of the benchmarks are benefiting from NEON. That would give a significant advantage, even at lower clock speeds, for algorithms that can be vectorized. (I'm also not sure to what extent the x86 benchmarks benefit from MMX/SSE.. so I'm not quite sure if for an apples-to-apples comparison neon should be utilized)
            I looked a bit at the internals of these benchmarks, trying to figure out why the results are so strange and unrealistic. And looks like a lot of fixes are badly needed. Some comments are in the Pandaboard ES thread: http://phoronix.com/forums/showthrea...096#post246096

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