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    SubjectRe: Scheduler Cleanup
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    On Mon, 2001-11-26 at 15:49, Davide Libenzi wrote:
    > On Mon, 26 Nov 2001, Mike Kravetz wrote:
    >
    > > I'm happy to see the cleanup of scheduler code that went into
    > > 2.4.15/16. One small difference in behavior (I think) is that
    > > the currently running task is not given preference over other
    > > tasks on the runqueue with the same 'goodness' value. I would
    > > think giving the current task preference is a good thing
    > > (especially in light of recent discussions about too frequent
    > > moving/rescheduling of tasks). Can someone provide the rational
    > > for this change? Was it just the result of making the code
    > > cleaner? Is it believed that this won't really make a difference?
    >
    > Mike, I was actually surprised about the presence of that check inside the
    > previous code.
    > If you think about it, when a running task is scheduled ?
    >
    > 1) an IRQ wakeup some I/O bound task
    > 2) the quota is expired
    >
    > With 1) you've an incoming I/O bound task ( ie: ksoftirqd_* ) that is very
    > likely going to have a better dynamic priority ( if not reschedule_idle()
    > does not set need_resched ), while with 2) you've the task counter == 0.
    > In both cases not only the test is useless but is going to introduce 1)
    > the branch in the fast path 2) the cost of an extra goodness().

    doesn't schedule() also get called when a new task is put on the
    runqueue?

    when that happens, doesn't the check matter? or perhaps I'm just
    mistaken.

    thanks,

    shaya


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