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sched: de-SCHED_OTHER-ize the RT path

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The current wake-up code path tries to determine if it can optimize the
wake-up to "this_cpu" by computing load calculations.  The problem is that
these calculations are only relevant to SCHED_OTHER tasks where load is king.
For RT tasks, priority is king.  So the load calculation is completely wasted
bandwidth.

Therefore, we create a new sched_class interface to help with
pre-wakeup routing decisions and move the load calculation as a function
of CFS task's class.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Gregory Haskins
2008-01-25 21:08:09 +01:00
committed by Ingo Molnar
parent 697f0a487f
commit e7693a362e
5 changed files with 195 additions and 140 deletions
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10
kernel/sched_rt.c
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@@ -150,6 +150,13 @@ yield_task_rt(struct rq *rq)
requeue_task_rt(rq, rq->curr);
}
#ifdef CONFIG_SMP
static int select_task_rq_rt(struct task_struct *p, int sync)
{
return task_cpu(p);
}
#endif /* CONFIG_SMP */
/*
* Preempt the current task with a newly woken task if needed:
*/
@@ -667,6 +674,9 @@ const struct sched_class rt_sched_class = {
.enqueue_task = enqueue_task_rt,
.dequeue_task = dequeue_task_rt,
.yield_task = yield_task_rt,
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_rt,
#endif /* CONFIG_SMP */
.check_preempt_curr = check_preempt_curr_rt,