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    SubjectRe: A quick fio test (was Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3)
    Ingo Molnar wrote:
    > * Avi Kivity <avi@argo.co.il> wrote:
    >
    >
    >> But what about cpu usage? At these low levels, the cpu is probably
    >> underutilized. It would be interesting to measure cpu time per I/O
    >> request (or, alternatively, use an I/O subsystem that can saturate the
    >> processors).
    >>
    >
    > yeah - that's what testing on ramdisk (Jens') or on a loopback block
    > device (mine) approximates to a certain degree.
    >
    >

    Ramdisks or fully cached loopback return immediately, so cache thrashing
    effects don't show up.

    Maybe a device mapper delay target or nbd + O_DIRECT can insert delays
    to make the workload more disk-like.




    --
    error compiling committee.c: too many arguments to function

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