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    SubjectRe: [PATCH] Prefaulting

    > >From a quick peek it seems that the patch makes negligible difference for a
    > kernel compilation when prefaulting 1-2 pages and slows the workload down
    > quite a lot when prefaulting up to 16 pages.

    well the last time I saw prefaulting experiments (Ingo was involved
    iirc) the problem was that the hitrate for the prefaults was such that
    the costs for tearing down the extra redundant rmap chains was more
    expensive than taking the "extra" faults. It seems linux has pretty
    cheap faulting logic invalidating some of traditional OS assumptions...

    (fwiw one of the worst tests I remember was doing a lot of very short
    shell script executions; the case where bash lives briefly so that you
    get maximum cost for the extra teardowns while not a lot of bash gets
    run so prefaulting doesn't make a lot of difference)

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      Last update: 2005-03-22 14:11    [W:0.027 / U:7.220 seconds]
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