| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | |
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| 3 | /* |
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| 4 | * Using the avg_vruntime, do the right thing and preserve lag across |
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| 5 | * sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled. |
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| 6 | */ |
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| 7 | SCHED_FEAT(PLACE_LAG, true) |
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| 8 | /* |
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| 9 | * Give new tasks half a slice to ease into the competition. |
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| 10 | */ |
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| 11 | SCHED_FEAT(PLACE_DEADLINE_INITIAL, true) |
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| 12 | /* |
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| 13 | * Preserve relative virtual deadline on 'migration'. |
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| 14 | */ |
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| 15 | SCHED_FEAT(PLACE_REL_DEADLINE, true) |
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| 16 | /* |
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| 17 | * Inhibit (wakeup) preemption until the current task has either matched the |
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| 18 | * 0-lag point or until is has exhausted it's slice. |
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| 19 | */ |
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| 20 | SCHED_FEAT(RUN_TO_PARITY, true) |
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| 21 | /* |
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| 22 | * Allow wakeup of tasks with a shorter slice to cancel RUN_TO_PARITY for |
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| 23 | * current. |
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| 24 | */ |
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| 25 | SCHED_FEAT(PREEMPT_SHORT, true) |
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| 26 | |
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| 27 | /* |
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| 28 | * Prefer to schedule the task we woke last (assuming it failed |
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| 29 | * wakeup-preemption), since its likely going to consume data we |
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| 30 | * touched, increases cache locality. |
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| 31 | */ |
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| 32 | SCHED_FEAT(NEXT_BUDDY, false) |
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| 33 | |
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| 34 | /* |
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| 35 | * Allow completely ignoring cfs_rq->next; which can be set from various |
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| 36 | * places: |
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| 37 | * - NEXT_BUDDY (wakeup preemption) |
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| 38 | * - yield_to_task() |
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| 39 | * - cgroup dequeue / pick |
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| 40 | */ |
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| 41 | SCHED_FEAT(PICK_BUDDY, true) |
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| 42 | |
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| 43 | /* |
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| 44 | * Consider buddies to be cache hot, decreases the likeliness of a |
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| 45 | * cache buddy being migrated away, increases cache locality. |
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| 46 | */ |
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| 47 | SCHED_FEAT(CACHE_HOT_BUDDY, true) |
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| 48 | |
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| 49 | /* |
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| 50 | * Delay dequeueing tasks until they get selected or woken. |
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| 51 | * |
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| 52 | * By delaying the dequeue for non-eligible tasks, they remain in the |
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| 53 | * competition and can burn off their negative lag. When they get selected |
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| 54 | * they'll have positive lag by definition. |
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| 55 | * |
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| 56 | * DELAY_ZERO clips the lag on dequeue (or wakeup) to 0. |
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| 57 | */ |
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| 58 | SCHED_FEAT(DELAY_DEQUEUE, true) |
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| 59 | SCHED_FEAT(DELAY_ZERO, true) |
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| 60 | |
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| 61 | /* |
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| 62 | * Allow wakeup-time preemption of the current task: |
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| 63 | */ |
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| 64 | SCHED_FEAT(WAKEUP_PREEMPTION, true) |
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| 65 | |
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| 66 | SCHED_FEAT(HRTICK, false) |
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| 67 | SCHED_FEAT(HRTICK_DL, false) |
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| 68 | |
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| 69 | /* |
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| 70 | * Decrement CPU capacity based on time not spent running tasks |
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| 71 | */ |
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| 72 | SCHED_FEAT(NONTASK_CAPACITY, true) |
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| 73 | |
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| 74 | #ifdef CONFIG_PREEMPT_RT |
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| 75 | SCHED_FEAT(TTWU_QUEUE, false) |
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| 76 | #else |
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| 77 | |
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| 78 | /* |
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| 79 | * Queue remote wakeups on the target CPU and process them |
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| 80 | * using the scheduler IPI. Reduces rq->lock contention/bounces. |
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| 81 | */ |
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| 82 | SCHED_FEAT(TTWU_QUEUE, true) |
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| 83 | #endif |
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| 84 | |
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| 85 | /* |
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| 86 | * When doing wakeups, attempt to limit superfluous scans of the LLC domain. |
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| 87 | */ |
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| 88 | SCHED_FEAT(SIS_UTIL, true) |
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| 89 | |
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| 90 | /* |
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| 91 | * Issue a WARN when we do multiple update_rq_clock() calls |
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| 92 | * in a single rq->lock section. Default disabled because the |
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| 93 | * annotations are not complete. |
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| 94 | */ |
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| 95 | SCHED_FEAT(WARN_DOUBLE_CLOCK, false) |
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| 96 | |
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| 97 | #ifdef HAVE_RT_PUSH_IPI |
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| 98 | /* |
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| 99 | * In order to avoid a thundering herd attack of CPUs that are |
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| 100 | * lowering their priorities at the same time, and there being |
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| 101 | * a single CPU that has an RT task that can migrate and is waiting |
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| 102 | * to run, where the other CPUs will try to take that CPUs |
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| 103 | * rq lock and possibly create a large contention, sending an |
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| 104 | * IPI to that CPU and let that CPU push the RT task to where |
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| 105 | * it should go may be a better scenario. |
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| 106 | */ |
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| 107 | SCHED_FEAT(RT_PUSH_IPI, true) |
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| 108 | #endif |
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| 109 | |
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| 110 | SCHED_FEAT(RT_RUNTIME_SHARE, false) |
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| 111 | SCHED_FEAT(LB_MIN, false) |
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| 112 | SCHED_FEAT(ATTACH_AGE_LOAD, true) |
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| 113 | |
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| 114 | SCHED_FEAT(WA_IDLE, true) |
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| 115 | SCHED_FEAT(WA_WEIGHT, true) |
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| 116 | SCHED_FEAT(WA_BIAS, true) |
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| 117 | |
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| 118 | /* |
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| 119 | * UtilEstimation. Use estimated CPU utilization. |
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| 120 | */ |
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| 121 | SCHED_FEAT(UTIL_EST, true) |
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| 122 | |
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| 123 | SCHED_FEAT(LATENCY_WARN, false) |
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| 124 | |
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