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    SubjectRe: A scrub daemon (prezeroing)
    Rik van Riel writes:

    > I'm not convinced. Zeroing a page takes 2000-4000 CPU
    > cycles, while faulting the page from RAM into cache takes
    > 200-400 CPU cycles per cache line, or 6000-12000 CPU
    > cycles.

    On my G5 it takes ~200 cycles to zero a whole page. In other words it
    takes about the same time to zero a page as to bring in a single cache
    line from memory. (PPC has an instruction to establish a whole cache
    line of zeroes in modified state without reading anything from

    Thus I can't see how prezeroing can ever be a win on ppc64.

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