OT: Increasing Ethernet receive buffer size on a wintel laptop - TCP-IP

This is a discussion on OT: Increasing Ethernet receive buffer size on a wintel laptop - TCP-IP ; I am sending as fast as I can over a 10 MbpS link data from my (DPS) system to a wintel notebook. It will not go much above 500 kbytes/sec., while when I receive things are OK. The wintel system ...

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Thread: OT: Increasing Ethernet receive buffer size on a wintel laptop

  1. OT: Increasing Ethernet receive buffer size on a wintel laptop

    I am sending as fast as I can over a 10 MbpS link data from
    my (DPS) system to a wintel notebook. It will not go much
    above 500 kbytes/sec., while when I receive things are OK.
    The wintel system is giving me a low tcp window size, something
    in the order of $4000 - and it does get full from time to time, which
    is
    the reason for the lower speed.
    I managed to locate how to change the windows tcp window size, and
    got it to $ffff. Well, it seems this was a "hard" ffff because the
    handshake stopped - segments begun to get lost and the speed
    degraded a lot (my retransmission is set pretty non-aggressively
    so I can spot things like that when they occur).
    The wintel network card "driver" can be set to have a receive
    ethernet
    buffer of up to 64k. Clearly it is too short - at the windows system
    latencies it would be more than naive to expect tcp to process it
    fast enough.
    Is there a solution to that - I mean someone who has wrestled this
    and would help? When it gets to windows I am just another TV-set user,
    don't know much except what I have had to deal with.
    The network adapter I can see is "Realtek RTL 8139 Family PCI
    Fast Ethenrnet NIC", the CPU is a 1.4GHz Intel.

    Thanks,

    Didi

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  2. Re: OT: Increasing Ethernet receive buffer size on a wintel laptop

    On 2008-05-16 09:25:05 -0400, Didi said:

    > The network adapter I can see is "Realtek RTL 8139 Family PCI
    > Fast Ethenrnet NIC", the CPU is a 1.4GHz Intel.


    I haven't had the world's greatest luck with Realtek NIC products, but
    I'm not here to product bash - just my own experience. The driver
    setting may not be what you're looking for, what you're probably
    wanting to do here is to tweak the TCP settings in the Windows registry
    to be more optimal for your connection type (LAN, DSL, T1, Other) to
    the Internet.

    A full discussion of all the parameters involved in this would be too
    long, and frankly, not productive in the newsgroup. You have the right
    idea, but the wrong set of settings you're trying to tweak.

    Try this link below as a starting point:

    > http://www.dslreports.com/drtcp


    While I'm not officially recommending this, you can probably find some
    lively discussions on Windows TCP/IP tweaking in the forums accessible
    there.

    Tweaking Windows Registry settings is not light stuff - always take a
    backup / perform a System Restore backup before changing things.
    Windows doesn't like being changed - it just likes wasting CPU on silly
    things. :P

    /dmfh

    --
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    \__,_|_|_|_|_| |_||_| dmfh(-2)dmfh.cx


  3. Re: OT: Increasing Ethernet receive buffer size on a wintel laptop

    Digital Mercenary For Honor -2- wrote:
    > ....
    >
    > Try this link below as a starting point:
    >
    > > http://www.dslreports.com/drtcp

    >


    It did exactly what I had done before - set the tcp size to $ffff
    (I put 65535 rather than 32768 in the box), modified the same
    "registry entry" which I had formerly discovered and manually
    created and deleted. Same effect of course - lost segments.
    Windows TCP happily reports all the time a window size of
    $ffff (I logged and checked that the first time, not now, but the
    behaviour and everything else was 100% the same) and does
    not manage to buffer all the incoming data.
    I would have expected a 1.4 GHz intel processor to be able
    to keep up with a saturated 10 MbpS channel, apparently not.
    I have no problems doing that at a fraction of the horsepowers
    I have on a 200 MHz PPC running DPS...
    But I am not so keen on solving this, what matters to me is
    that my part is OK, let MS worry about theirs, I can live
    as things are. It would be nice if I could double the speed
    towards that notebook but it is no life and death issue.

    Thanks,

    Didi

    ------------------------------------------------------
    Dimiter Popoff Transgalactic Instruments

    http://www.tgi-sci.com
    ------------------------------------------------------
    http://www.flickr.com/photos/didi_tg...7600228621276/

    Original message:http://groups.google.com/group/comp.protocols.tcp-ip/
    msg/4bfbe239013fd15f?dmode=source

  4. Re: OT: Increasing Ethernet receive buffer size on a wintel laptop

    On 2008-05-17 20:17:38 -0400, Didi said:

    > But I am not so keen on solving this, what matters to me is
    > that my part is OK, let MS worry about theirs, I can live
    > as things are. It would be nice if I could double the speed
    > towards that notebook but it is no life and death issue.



    Indeed. This is personal bane of my I'd love to see you solve, since
    only M$ products make it so difficult to change what are really basic
    TCP/IP parameters (*growls with geek rage*). There is a "professional"
    product called TweakMaster Pro that will allow you to get access to all
    the parameters necessary to fine tune your Windows TCP/IP stack. It's a
    number of parameters that need to be changed, not just one or two, and
    unfortunately, M$ moves them around to different Registry entries from
    time to time without documenting them.

    Good luck to you.

    /dmfh


    --
    _ __ _
    __| |_ __ / _| |_ 01100100 01101101
    / _` | ' \| _| ' \ 01100110 01101000
    \__,_|_|_|_|_| |_||_| dmfh(-2)dmfh.cx


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