lkml.org 
[lkml]   [2004]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    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
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:04    [from the cache]
    ©2003-2014 Jasper Spaans. hosted at Digital Ocean