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    SubjectRe: Kernel-bound applications?
    > Two things you might like to consider (they aren't necessarily
    > easy;-):
    > - direct copying from writing process to reading process. This would
    > require you to read the page tables of the reading process so you can
    > copy_from_user() to the physical pages of the reading process. You'll
    > need to pin down the reading process pages

    I was thinking about this method. For blocking reads and writes, it seems
    like it would work great. But since X uses non-blocking i/o, I didn't
    really look into it. Anyone want to comment further on the feasibility?
    Perhaps a test in unix_stream_sendmsg and unix_stream_recvmsg that checks
    to see if it is a blocking socket and if true, does the direct copy.

    > - when user buffers are page aligned and at least one page in size, do
    > page flipping.

    I think I'll let someone else try this method :)

    > Both these techniques require page table accesses, which will have
    > some overhead. You might also need to consider cache issues.
    > Do it and benchmark it :-)

    I think I'll try the direct copy mechanism this weekend, along with some
    other ideas.

    Kirk Petersen

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