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    SubjectRe: [PATCH] V-3.0 Single Priority Array O(1) CPU Scheduler Evaluation
    William Lee Irwin III wrote:
    >> Aperiodic rotations defer movement until MAX_RT_PRIO's slot is evacuated.

    On Wed, Aug 04, 2004 at 11:36:59AM +1000, Peter Williams wrote:
    > Unfortunately, to ensure no starvation, promotion has to continue even
    > when there are tasks in MAX_RT_PRIO's slot.

    One may either demote to evict MAX_RT_PRIO immediately prior to
    rotation or rely on timeslice expiry to evict MAX_RT_PRIO. Forcibly
    evicting MAX_RT_PRIO undesirably accumulates tasks at the fencepost.

    William Lee Irwin III wrote:
    >> The primary concern was that ticklessness etc. may require it to occur
    >> during context switches.

    On Wed, Aug 04, 2004 at 11:36:59AM +1000, Peter Williams wrote:
    > On a tickless system, I'd consider using a timer to control when
    > do_promotions() gets called. I imagine something similar will be
    > necessary to manage time slices?

    This is an alternative to scheduler accounting in context switches.
    Periodicity often loses power conservation benefits.

    -- wli
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