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76cae9dbe1
Removes the FAIR_SLEEPERS code in favour of the new LAG based placement. Specifically, the whole FAIR_SLEEPER thing was a very crude approximation to make up for the lack of lag based placement, specifically the 'service owed' part. This is important for things like 'starve' and 'hackbench'. One side effect of FAIR_SLEEPER is that it caused 'small' unfairness, specifically, by always ignoring up-to 'thresh' sleeptime it would have a 50%/50% time distribution for a 50% sleeper vs a 100% runner, while strictly speaking this should (of course) result in a 33%/67% split (as CFS will also do if the sleep period exceeds 'thresh'). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230531124604.000198861@infradead.org
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Using the avg_vruntime, do the right thing and preserve lag across
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* sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled.
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*/
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SCHED_FEAT(PLACE_LAG, true)
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SCHED_FEAT(PLACE_DEADLINE_INITIAL, 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 likeliness 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(HRTICK_DL, false)
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SCHED_FEAT(DOUBLE_TICK, false)
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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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#ifdef CONFIG_PREEMPT_RT
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SCHED_FEAT(TTWU_QUEUE, false)
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#else
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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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#endif
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/*
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* When doing wakeups, attempt to limit superfluous scans of the LLC domain.
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*/
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SCHED_FEAT(SIS_PROP, false)
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SCHED_FEAT(SIS_UTIL, true)
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/*
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* Issue a WARN when we do multiple update_rq_clock() calls
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* in a single rq->lock section. Default disabled because the
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* annotations are not complete.
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*/
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SCHED_FEAT(WARN_DOUBLE_CLOCK, false)
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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(RT_RUNTIME_SHARE, false)
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SCHED_FEAT(LB_MIN, false)
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SCHED_FEAT(ATTACH_AGE_LOAD, true)
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SCHED_FEAT(WA_IDLE, true)
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SCHED_FEAT(WA_WEIGHT, true)
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SCHED_FEAT(WA_BIAS, true)
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/*
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* UtilEstimation. Use estimated CPU utilization.
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*/
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SCHED_FEAT(UTIL_EST, true)
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SCHED_FEAT(UTIL_EST_FASTUP, true)
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SCHED_FEAT(LATENCY_WARN, false)
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SCHED_FEAT(ALT_PERIOD, true)
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SCHED_FEAT(BASE_SLICE, true)
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SCHED_FEAT(EEVDF, true)
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