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    SubjectRe: Stolen and degraded time and schedulers
    Daniel Walker wrote:
    >> I suppose you could, but that seems more complex. I think you could
    >> encode the same information in the measurement of how much work a cpu
    >> actually got done while a process was scheduled on it.
    >>
    >
    > I know it's more complex, but that seems more like the "right" thing to
    > do.

    Why's that?

    I'm proposing that rather than using "time spent scheduled" as an
    approximation of how much progress a process made on a particular CPU
    during its timeslice, we should measure it directly. It seems to me that
    this usefully encapsulates both the problems of variable-speed cpus and
    hypervisors stealing time from guests.

    The actual length of the timeslices is an orthogonal issue. It may be
    that you want to give processes more cpu time by making their quanta
    longer to compensate for lost cpu time, but that would affect their
    real-time characteristics. Or you could keep the quanta small, and give
    those processes more of them.

    But all this is getting deep into scheduler design, which is not what I
    want to get into; I'm just proposing a better metric for a scheduler to
    use in whatever way it wants.

    J
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