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    SubjectZerocopy implementation issues
    Hi,

    Can someone please explain to me the rationale behind the zerocopy
    implementation that has appeared in 2.4.4 please?

    The reason I ask is that even on x86, it seems to me to be extremely
    silly to have the expense of doing unaligned checksumming for the gain
    of zerocopy.

    Just think - if you did checksumming on aligned word boundaries you
    could be far faster!

    (Yes, you guessed it, its broken on ARM, and is going to make the
    networking layer pig slow if we keep the current implementation as
    it stands due to the phenominal amount of exceptions it _will_
    generate - 1 exception per word in a packet).

    I'm still investigating the source of the networking corruptions I'm
    seeing, but its looking like the above is the reason (data is being
    corrupted on TCP send).

    --
    Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
    http://www.arm.linux.org.uk/personal/aboutme.html

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