b043eb7320
This patch introduces the ENERGY_AWARE sched feature, which is implemented using jump labels when SCHED_DEBUG is defined. It is statically set false when SCHED_DEBUG is not defined. Hence this doesn't allow energy awareness to be enabled without SCHED_DEBUG. This sched_feature knob will be replaced later with a more appropriate control knob when things have matured a bit. ENERGY_AWARE is based on per-entity load-tracking hence FAIR_GROUP_SCHED must be enable. This dependency isn't checked at compile time yet. cc: Ingo Molnar <mingo@redhat.com> cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
76 lines
2.1 KiB
C
76 lines
2.1 KiB
C
/*
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* Only give sleepers 50% of their service deficit. This allows
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* them to run sooner, but does not allow tons of sleepers to
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* rip the spread apart.
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*/
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SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
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/*
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* Place new tasks ahead so that they do not starve already running
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* tasks
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*/
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SCHED_FEAT(START_DEBIT, true)
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/*
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* Prefer to schedule the task we woke last (assuming it failed
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* wakeup-preemption), since its likely going to consume data we
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* touched, increases cache locality.
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*/
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SCHED_FEAT(NEXT_BUDDY, false)
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/*
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* Prefer to schedule the task that ran last (when we did
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* wake-preempt) as that likely will touch the same data, increases
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* cache locality.
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*/
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SCHED_FEAT(LAST_BUDDY, true)
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/*
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* Consider buddies to be cache hot, decreases the likelyness of a
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* cache buddy being migrated away, increases cache locality.
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*/
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SCHED_FEAT(CACHE_HOT_BUDDY, true)
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/*
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* Allow wakeup-time preemption of the current task:
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*/
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SCHED_FEAT(WAKEUP_PREEMPTION, true)
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SCHED_FEAT(HRTICK, false)
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SCHED_FEAT(DOUBLE_TICK, false)
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SCHED_FEAT(LB_BIAS, true)
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/*
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* Decrement CPU capacity based on time not spent running tasks
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*/
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SCHED_FEAT(NONTASK_CAPACITY, true)
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/*
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* Queue remote wakeups on the target CPU and process them
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* using the scheduler IPI. Reduces rq->lock contention/bounces.
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*/
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SCHED_FEAT(TTWU_QUEUE, true)
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#ifdef HAVE_RT_PUSH_IPI
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/*
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* In order to avoid a thundering herd attack of CPUs that are
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* lowering their priorities at the same time, and there being
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* a single CPU that has an RT task that can migrate and is waiting
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* to run, where the other CPUs will try to take that CPUs
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* rq lock and possibly create a large contention, sending an
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* IPI to that CPU and let that CPU push the RT task to where
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* it should go may be a better scenario.
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*/
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SCHED_FEAT(RT_PUSH_IPI, true)
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#endif
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SCHED_FEAT(FORCE_SD_OVERLAP, false)
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SCHED_FEAT(RT_RUNTIME_SHARE, true)
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SCHED_FEAT(LB_MIN, false)
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SCHED_FEAT(ATTACH_AGE_LOAD, true)
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/*
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* Energy aware scheduling. Use platform energy model to guide scheduling
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* decisions optimizing for energy efficiency.
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*/
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SCHED_FEAT(ENERGY_AWARE, false)
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