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sched: Feature to disable APERF/MPERF cpu_power

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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: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-09-03 13:20:03 +02:00 • committed by Ingo Molnar
parent 47fe38fcff
commit 8e6598af3f
2 changed files with 15 additions and 2 deletions
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12
kernel/sched.c
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@ -3602,11 +3602,19 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
unsigned long power = SCHED_LOAD_SCALE; unsigned long power = SCHED_LOAD_SCALE;
struct sched_group *sdg = sd->groups; struct sched_group *sdg = sd->groups;
power *= arch_scale_freq_power(sd, cpu); if (sched_feat(ARCH_POWER))
power *= arch_scale_freq_power(sd, cpu);
else
power *= default_scale_freq_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT; power >>= SCHED_LOAD_SHIFT;
if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
power *= arch_scale_smt_power(sd, cpu); if (sched_feat(ARCH_POWER))
power *= arch_scale_smt_power(sd, cpu);
else
power *= default_scale_smt_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT; power >>= SCHED_LOAD_SHIFT;
} }

5
kernel/sched_features.h
View file

@ -82,6 +82,11 @@ SCHED_FEAT(LAST_BUDDY, 1)
*/ */
SCHED_FEAT(CACHE_HOT_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(HRTICK, 0)
SCHED_FEAT(DOUBLE_TICK, 0) SCHED_FEAT(DOUBLE_TICK, 0)
SCHED_FEAT(LB_BIAS, 1) SCHED_FEAT(LB_BIAS, 1)