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    SubjectRE: [PATCH 04/18] csum_and_copy_..._user(): pass 0xffffffff instead of 0 as initial sum
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    From: Al Viro
    > Sent: 23 July 2020 16:21
    ...
    > The point is, your "~4.5 cycles per vector" is pretty much noise and the
    > difference between the 3-argument and 4-argument variants could easily be
    > in the same range. It might be a valid microoptimization, it might be not.
    > 3-argument variant is simpler and IMO in absence of strong data we ought
    > to go with that.

    There is definitely more to be gained by rewriting the x86-86 asm.

    David

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