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Commit 1b9508f6 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

sched: Rate-limit newidle 



Rate limit newidle to migration_cost. It's a win for all
stages of sysbench oltp tests.

Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a1f84a3a

kernel/sched.c

+21 −1
Original line number Diff line number Diff line
@@ -589,6 +589,8 @@ struct rq { 


	u64 rt_avg;

	u64 age_stamp;

	u64 idle_stamp;

	u64 avg_idle;

#endif



	/* calc_load related fields */
@@ -2353,6 +2355,17 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, 
	if (rq != orig_rq)

		update_rq_clock(rq);



	if (rq->idle_stamp) {

		u64 delta = rq->clock - rq->idle_stamp;

		u64 max = 2*sysctl_sched_migration_cost;



		if (delta > max)

			rq->avg_idle = max;

		else

			update_avg(&rq->avg_idle, delta);

		rq->idle_stamp = 0;

	}



	WARN_ON(p->state != TASK_WAKING);

	cpu = task_cpu(p);
@@ -4389,6 +4402,11 @@ static void idle_balance(int this_cpu, struct rq *this_rq) 
	int pulled_task = 0;

	unsigned long next_balance = jiffies + HZ;



	this_rq->idle_stamp = this_rq->clock;



	if (this_rq->avg_idle < sysctl_sched_migration_cost)

		return;



	for_each_domain(this_cpu, sd) {

		unsigned long interval;
@@ -4403,9 +4421,11 @@ static void idle_balance(int this_cpu, struct rq *this_rq) 
		interval = msecs_to_jiffies(sd->balance_interval);

		if (time_after(next_balance, sd->last_balance + interval))

			next_balance = sd->last_balance + interval;

		if (pulled_task)

		if (pulled_task) {

			this_rq->idle_stamp = 0;

			break;

		}

	}

	if (pulled_task || time_after(jiffies, this_rq->next_balance)) {

		/*

		 * We are going idle. next_balance may be set based on

kernel/sched_debug.c

+4 −0
Original line number Diff line number Diff line
@@ -285,12 +285,16 @@ static void print_cpu(struct seq_file *m, int cpu) 


#ifdef CONFIG_SCHEDSTATS

#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);

#define P64(n) SEQ_printf(m, "  .%-30s: %Ld\n", #n, rq->n);



	P(yld_count);



	P(sched_switch);

	P(sched_count);

	P(sched_goidle);

#ifdef CONFIG_SMP

	P64(avg_idle);

#endif



	P(ttwu_count);

	P(ttwu_local);