Messages in this thread |  | | Subject | Re: zero-copy TCP | From | Jes Sorensen <> | Date | 03 Sep 2000 03:20:13 +0200 |
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>>>>> "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.
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