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Commit ab29230e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Implement dynamic cpu_power 



Recompute the cpu_power for each cpu during load-balance.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: default avatarAndreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: default avatarAndreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: default avatarGautham R Shenoy <ego@in.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
LKML-Reference: <20090901083826.162033479@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a52bfd73

kernel/sched.c

+35 −3
Original line number Diff line number Diff line
@@ -3699,14 +3699,46 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, 
}

#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */



static void update_sched_power(struct sched_domain *sd)

unsigned long __weak arch_smt_gain(struct sched_domain *sd, int cpu)

{

	unsigned long weight = cpumask_weight(sched_domain_span(sd));

	unsigned long smt_gain = sd->smt_gain;



	smt_gain /= weight;



	return smt_gain;

}



static void update_cpu_power(struct sched_domain *sd, int cpu)

{

	unsigned long weight = cpumask_weight(sched_domain_span(sd));

	unsigned long power = SCHED_LOAD_SCALE;

	struct sched_group *sdg = sd->groups;

	unsigned long old = sdg->__cpu_power;



	/* here we could scale based on cpufreq */



	if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {

		power *= arch_smt_gain(sd, cpu);

		power >>= SCHED_LOAD_SHIFT;

	}



	/* here we could scale based on RT time */



	if (power != old) {

		sdg->__cpu_power = power;

		sdg->reciprocal_cpu_power = reciprocal_value(power);

	}

}



static void update_group_power(struct sched_domain *sd, int cpu)

{

	struct sched_domain *child = sd->child;

	struct sched_group *group, *sdg = sd->groups;

	unsigned long power = sdg->__cpu_power;



	if (!child) {

		/* compute cpu power for this cpu */

		update_cpu_power(sd, cpu);

		return;

	}
@@ -3749,7 +3781,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, 
	if (local_group) {

		balance_cpu = group_first_cpu(group);

		if (balance_cpu == this_cpu)

			update_sched_power(sd);

			update_group_power(sd, this_cpu);

	}



	/* Tally up the load of all CPUs in the group */