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