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    SubjectRe: [patch] CFS scheduler, -v15
    On Wed, Jun 06, 2007 at 01:19:01PM +0200, Dmitry Adamushko wrote:
    > >Yes this is the approach I prefer, because we burden the fast/normal
    > >path less that way (RT->NORMAL transition is not common).
    > I don't think that rt_sched_class :: dequeue_task_rt() is in any of
    > such "fast pathes" that we should really care about an additional
    > math. operation.
    > If this approach is ok, logically-wise (no side effects from a short
    > 'delta_exec', esp. on RT -> NORMAL).. I think it's better as it keeps
    > the 'sched_class' interface simpler.

    I can see your point, given that we just update exec_start in
    dequeue_task_rt(). However the situation is slightly more complex in my
    patch stack, as I need to update other things during group change. Perhaps
    we can postpone this discussion until I post that patch stack.

    > >That's why I
    > >was considering a set_curr_task() method in fair_sched_class which will
    > >be invoked in __setscheduler() if the new policy of currently running
    > >task happens to be SCHED_NORMAL/BATCH. Alternately if the new policy of
    > >currently running task happens to be SCHED_FIFO (and its old policy was
    > >SCHED_NORMAL) we need to invoke put_prev_task() method (so that
    > >fair_clock etc is updated based on outgoing task's execution time in
    > >SCHED_NORMAL class).
    > rt_sched_class :: put_prev_task() from __setscheduler() ?

    No, fair_sched_class :: put_prev_task() if we are transitioning from
    NORMAL->RT. That will update the fair_clock based on execution time
    of current task in fair_sched class?

    > But it's not
    > supposed to be called from here, logically-wise. You just rely on its
    > current behavior (which is only about updating 'exec_start' and
    > 'exec_sum') -- that's just bad. Maybe I misunderatood your intention
    > though..

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      Last update: 2007-06-06 13:31    [W:0.023 / U:2.060 seconds]
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