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Subject[PATCH 8/8] use avg_vruntime for task placement
Allow to use the avg_vruntime for task placement.

The pro: its the 'fair' place to insert tasks.
The con: its an extra division.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/sched.c | 9 +++++++--
kernel/sched_fair.c | 7 ++++++-
kernel/sched_features.h | 1 +
3 files changed, 14 insertions(+), 3 deletions(-)

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -1847,8 +1847,13 @@ void set_task_cpu(struct task_struct *p,
schedstat_inc(p, se.nr_forced2_migrations);
}
#endif
- p->se.vruntime -= old_cfsrq->min_vruntime -
- new_cfsrq->min_vruntime;
+ if (sched_feat(AVG_VRUNTIME)) {
+ p->se.vruntime -=
+ avg_vruntime(old_cfsrq) - avg_vruntime(new_cfsrq);
+ } else {
+ p->se.vruntime -=
+ old_cfsrq->min_vruntime - new_cfsrq->min_vruntime;
+ }

__set_task_cpu(p, new_cpu);
}
Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -719,7 +719,12 @@ static void check_spread(struct cfs_rq *
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
{
- u64 vruntime = cfs_rq->min_vruntime;
+ u64 vruntime;
+
+ if (sched_feat(AVG_VRUNTIME))
+ vruntime = avg_vruntime(cfs_rq);
+ else
+ vruntime = cfs_rq->min_vruntime;

/*
* The 'current' period is already promised to the current tasks,
Index: linux-2.6/kernel/sched_features.h
===================================================================
--- linux-2.6.orig/kernel/sched_features.h
+++ linux-2.6/kernel/sched_features.h
@@ -11,4 +11,5 @@ SCHED_FEAT(ASYM_GRAN, 1)
SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)
+SCHED_FEAT(AVG_VRUNTIME, 0)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
--



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