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    SubjectRe: [patch] new scheduler
    On Mon, 10 May 1999, Rogier Wolff wrote:
    > Rik van Riel wrote:
    > >
    > > No. Interactive processes that don't use up their time slice
    > > before jiffies reaches p->defer will get their time slice
    > > fully reinstated in wake_up_process().
    >
    > Ah, but this is bad.
    >
    > The constant would be tuned to fill about 80 or 90% of a timer tick.
    > The program would run for 2.5 times as much real-time compared to when
    > the "usleep" wasn't there, but it would get accounted for less than
    > 10% of the original CPU time!

    It seems like I wasn't clear in my explanation...

    In wake_up_process():
    + if (time_after(jiffies, p->defer)) {
    + p->defer = jiffies;
    + p->counter = p->priority;
    + }

    If a process _does_ use up it's time slice, defer
    will be set so far away that this code will only
    be triggered if the task uses less than 33% of the
    CPU with a system load of 2...

    There might be some brain farts left, but I don't
    think I fell for that trap :)

    Rik -- Open Source: you deserve to be in control of your data.
    +-------------------------------------------------------------------+
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    | Linux Memory Management site: http://humbolt.geo.uu.nl/Linux-MM/ |
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    +-------------------------------------------------------------------+


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