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Commit 13814d42 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

sched: Remove ASYM_GRAN feature 



This features has been enabled for quite a while, after testing showed that
easing preemption for light tasks was harmful to high priority threads.

Remove the feature flag.

Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301675.6785.44.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c6ee36c4

kernel/sched_fair.c

+11 −17
Original line number Diff line number Diff line
@@ -1583,9 +1583,7 @@ wakeup_gran(struct sched_entity *curr, struct sched_entity *se) 
	/*

	 * Since its curr running now, convert the gran from real-time

	 * to virtual-time in his units.

	 */

	if (sched_feat(ASYM_GRAN)) {

		/*

	 *

	 * By using 'se' instead of 'curr' we penalize light tasks, so

	 * they get preempted easier. That is, if 'se' < 'curr' then

	 * the resulting gran will be larger, therefore penalizing the
@@ -1597,10 +1595,6 @@ wakeup_gran(struct sched_entity *curr, struct sched_entity *se) 
	 */

	if (unlikely(se->load.weight != NICE_0_LOAD))

		gran = calc_delta_fair(gran, se);

	} else {

		if (unlikely(curr->load.weight != NICE_0_LOAD))

			gran = calc_delta_fair(gran, curr);

	}



	return gran;

}

kernel/sched_features.h

+0 −6
Original line number Diff line number Diff line
@@ -16,12 +16,6 @@ SCHED_FEAT(START_DEBIT, 1) 
 */

SCHED_FEAT(WAKEUP_PREEMPT, 1)



/*

 * When converting the wakeup granularity to virtual time, do it such

 * that heavier tasks preempting a lighter task have an edge.

 */

SCHED_FEAT(ASYM_GRAN, 1)



/*

 * Based on load and program behaviour, see if it makes sense to place

 * a newly woken task on the same cpu as the task that woke it --