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Re: [nslu2-linux] Re: Big endian vs Little endian and Network performance

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  • Yann E. MORIN
    David, All, ... I guess that 1TB (Terra Byte, 1024GiB) would be _expensive_, unless the B stands for bit , in which case 128GiB would _still_ be
    Message 1 of 45 , Jul 3, 2006
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      David,
      All,

      On Monday 03 July 2006 114, David Given wrote:
      > Yann E. MORIN wrote:
      > > Hmm, donuts!... :-) Anyway i would not entrust flash-based hard-drive, wether
      > One of these, then?
      > http://atomchip.com/_wsn/page3.html

      I guess that 1TB (Terra Byte, 1024GiB) would be _expensive_, unless the 'B'
      stands for 'bit', in which case 128GiB would _still_ be expensive...
      But yes, for those who don't want to touch the hardware in the slug...
      But if one has enough money to put in one of those, certainly he/she's not
      using a slug... :-)

      > Yeah, but he said he was using smbclient, which AFAIK does not cache ---
      > it lives entirely in user space and is the SMB equivalent of ftp.

      smbclient no, but the kernel? Let me think about it a minute... ... ... No,
      I can't come with an answer... You must be right there, I was wrong (and I
      don't often have to admit it, which I don't like ever :-]]] )

      > Are you using the internal ethernet, or a USB widget?

      Build-in. I know by experience that the ixp400_eth.ko module is very badly
      written, that the underlying AccessLibrary (the CSR) is equally badly written,
      and that only having proper code would certainly gain in favor of speed. But
      that's a loooong way... :-(

      > I know that USB mass storage is quite expensive in CPU terms, but I
      > don't know whether that applies to networking. It would be interesting
      > to compare the two interfaces, though.

      Good question. Would we gain speed by using an USB-to-ethernet adapter,
      and not using the build-in ethernet port? Or even using trunking? Worth a try,
      but I have no such device at hand... :-/

      Note that in my experiments, I was not touching USB at all.

      > One thing I need to try doing is to swapping USB drive enclosures over
      > between my cheap-and-nasty Iomega (currently in use on the NSLU2) and my
      > older but more expensive Maxtor One-Touch. My NSLU2 is always rather
      > busy --- it's currently got a load of 6.4/5.6/3.7 --- and any
      > improvement would help...

      I'm not sure adding a better (which means 'faster') USB2IDE adapter would
      lower your load. On the contrary, accelearting USB transfert might simply
      increase it, as usb-storage would then eat more of your CPU. :-/

      Regards,
      Yann E. MORIN.

      --
      .-----------------.--------------------.------------------.--------------------.
      | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
      | +0/33 662376056 | Software Designer | \ / CAMPAIGN | ^ |
      | --==< °_° >==-- °---.----------------: X AGAINST | /e\ There is no |
      | web: ymorin.free.fr | SETI@home 3808 | / \ HTML MAIL | """ conspiracy. |
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    • Yann E. MORIN
      Brian, All, ... Looks like it s OK. :-) ... [--SNIP--] ... So hand-adding swap only when you need it for sure (compilation, install of packages, etc..) Yes,
      Message 45 of 45 , Jul 3, 2006
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        Brian,
        All,

        On Monday 03 July 2006 002, Brian Wood wrote:
        > [Don't know if changing the subject will preserve the threading or not]

        Looks like it's OK. :-)

        > On Jul 2, 2006, at 3:37 PM, Yann E. MORIN wrote:
        > >> Something like this:
        > >> http://www.geeks.com/details.asp?invtid=77P1636&cat=HDD
        > > Hmm, donuts!... :-) Anyway i would not entrust flash-based hard-
        > > drive, wether
        [--SNIP--]
        > I'll grant all of that, but once I get the thing going I hardly touch
        > swap at all, and that thing does seem *fast*, but I suspect the
        > limiting factor is the IDE-USB transition, so it might not be any
        > faster than a normal 4200 rpm drive.

        So hand-adding swap only when you need it for sure (compilation, install
        of packages, etc..) Yes, why not. Then that's not that bad. But still I'm
        amazed at the figures they show. Seems pretty fast for flash.

        > If the cycle number is correct on that, and they are "spreading the
        > load", I could live with having to replace the drive every year, if
        > it actually gave me a speed boost.

        Surely they are doing wear-leveling on [dr]ecent flash memories.

        > I suppose the only way to know for sure is to buy one and play with
        > it, $99 for a 2GB, oh well, it's only money.

        Be my guest. Tell us about your conclusions! :-)

        > > Maximum load when receiving: 0.94. That's really, really _big_.
        > > So what does that _mean_? It looks like we _are_ CPU-bound on the
        > > slug, and thus
        > > it can not even sustain receiving more than around 48Mibps. That is
        > > _receiving_.
        > I guess I'm not surprised, for <$100 :-)

        Yes, I can't imagine with a 133Mhz slug... :-/ Anyway, that's a good buy,
        and you get what you pay for: a good little hardware really easy to play with,
        a NAS that will fulfill most of your desires reagarding file access (except if
        you are dumb enough to have your /home on it (I am!)) and a little box that is
        quite good-looking after all.

        > > Looking at the WiKi, there is a section on using the DMA
        > > accelerations from the
        > > NPEs. That could help, but yet... :-/
        > So it looks like 48Mibps is about it, and the most helpful
        > improvement would probably be from a better network driver.

        Such as an USB-to-ethernet adapter, as David suggests. But again, we might
        see a bottleneck between usb-storage and usb-ethernet... :-/

        Anyway, if anyone can conduct the same tests with such a device, please tell
        us.

        > Much thanks for the information.

        You're welcome. I was enlighten as well by this very instructive experiment.
        At last I know how I can entrust my slug regarding file-serving speeds.

        Regards,
        Yann E. MORIN.

        --
        .-----------------.--------------------.------------------.--------------------.
        | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
        | +0/33 662376056 | Software Designer | \ / CAMPAIGN | ^ |
        | --==< °_° >==-- °---.----------------: X AGAINST | /e\ There is no |
        | web: ymorin.free.fr | SETI@home 3808 | / \ HTML MAIL | """ conspiracy. |
        °---------------------°----------------°------------------°--------------------°
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