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Commit 3b3d190e authored by Paul Turner's avatar Paul Turner Committed by Ingo Molnar
Browse files

sched: Implement demand based update_cfs_load() 



When the system is busy, dilation of rq->next_balance makes lb->update_shares()
insufficiently frequent for threads which don't sleep (no dequeue/enqueue
updates).  Adjust for this by making demand based updates based on the
accumulation of execution time sufficient to wrap our averaging window.

Signed-off-by: default avatarPaul Turner <pjt@google.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101115234938.291159744@google.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c66eaf61

kernel/sched.c

+8 −1
Original line number Diff line number Diff line
@@ -353,9 +353,16 @@ struct cfs_rq { 
	 */

	unsigned long h_load;



	/*

	 * Maintaining per-cpu shares distribution for group scheduling

	 *

	 * load_stamp is the last time we updated the load average

	 * load_last is the last time we updated the load average and saw load

	 * load_unacc_exec_time is currently unaccounted execution time

	 */

	u64 load_avg;

	u64 load_period;

	u64 load_stamp, load_last;

	u64 load_stamp, load_last, load_unacc_exec_time;



	unsigned long load_contribution;

#endif

kernel/sched_fair.c

+12 −0
Original line number Diff line number Diff line
@@ -539,6 +539,9 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) 
	return calc_delta_fair(sched_slice(cfs_rq, se), se);

}



static void update_cfs_load(struct cfs_rq *cfs_rq);

static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta);



/*

 * Update the current task's runtime statistics. Skip current tasks that

 * are not in our scheduling class.
@@ -558,6 +561,14 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, 


	curr->vruntime += delta_exec_weighted;

	update_min_vruntime(cfs_rq);



#ifdef CONFIG_FAIR_GROUP_SCHED

	cfs_rq->load_unacc_exec_time += delta_exec;

	if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {

		update_cfs_load(cfs_rq);

		update_cfs_shares(cfs_rq, 0);

	}

#endif

}



static void update_curr(struct cfs_rq *cfs_rq)
@@ -713,6 +724,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq) 
	}



	cfs_rq->load_stamp = now;

	cfs_rq->load_unacc_exec_time = 0;

	cfs_rq->load_period += delta;

	if (load) {

		cfs_rq->load_last = now;