Re: zero-copy TCP

From: Jeff V. Merkey (jmerkey@timpanogas.com)
Date: Sat Sep 02 2000 - 22:07:36 EDT

  • Next message: Jeff V. Merkey: "Re: zero-copy TCP"

    There's been a few cards around since about 1995, but I don't remember
    all of them. I do remember having to debug SMP code on them though --
    yechhhh!!!!

    Jeff

    Jes Sorensen wrote:
    >
    > >>>>> "Jeff" == Jeff V Merkey <jmerkey@timpanogas.com> writes:
    >
    > Jeff> Jes Sorensen wrote:
    > >> You just told us earlier in the thread that NetWare does direct
    > >> zero copy DMA but thats only half the story obviously. Up until the
    > >> era of Gigabit Ethernet cards there were almost no PCI cards
    > >> available that would do scatter/gather so obviously netware wasn't
    > >> doing zero copy either.
    >
    > Jeff> I guess this is a correct statement, but Linux and everyone else
    > Jeff> has the same limittion. Here, I'll refrase. Zero copies
    > Jeff> irregardless of the driver model. Intel had an ethernet card
    > Jeff> that did years back. So Alan's statements are also wrong since
    > Jeff> he says "one DMA" not applicable to cards with a shared memory
    > Jeff> window.
    >
    > I know cards exist that can do the job, however it has first become
    > widely available with the Gigabit cards. I only know of a few 100baseT
    > cards that can do it such as the Adaptec Starfire and the 3C905B
    > (though I am not sure what it provides is sufficient). As for the
    > Intel EEPro100 series than it's probably true they can do it, but we
    > were never allowed to get information on the magic to enable it.
    >
    > We are working on zero copy and it makes sense for some stuff, but
    > it's not as simple an issue as a lot of people make it out to be.
    >
    > Jes
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