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Commit 8e6598af authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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sched: Feature to disable APERF/MPERF cpu_power 



I suspect a feed-back loop between cpuidle and the aperf/mperf
cpu_power bits, where when we have idle C-states lower the ratio,
which leads to lower cpu_power and then less load, which generates
more idle time, etc..

Put in a knob to disable it.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 47fe38fc

kernel/sched.c

+10 −2
Original line number Diff line number Diff line
@@ -3602,11 +3602,19 @@ static void update_cpu_power(struct sched_domain *sd, int cpu) 
	unsigned long power = SCHED_LOAD_SCALE;

	struct sched_group *sdg = sd->groups;



	if (sched_feat(ARCH_POWER))

		power *= arch_scale_freq_power(sd, cpu);

	else

		power *= default_scale_freq_power(sd, cpu);



	power >>= SCHED_LOAD_SHIFT;



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

		if (sched_feat(ARCH_POWER))

			power *= arch_scale_smt_power(sd, cpu);

		else

			power *= default_scale_smt_power(sd, cpu);



		power >>= SCHED_LOAD_SHIFT;

	}

kernel/sched_features.h

+5 −0
Original line number Diff line number Diff line
@@ -82,6 +82,11 @@ SCHED_FEAT(LAST_BUDDY, 1) 
 */

SCHED_FEAT(CACHE_HOT_BUDDY, 1)



/*

 * Use arch dependent cpu power functions

 */

SCHED_FEAT(ARCH_POWER, 0)



SCHED_FEAT(HRTICK, 0)

SCHED_FEAT(DOUBLE_TICK, 0)

SCHED_FEAT(LB_BIAS, 1)