1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 /* 4 * Only give sleepers 50% of their service deficit. This allows 5 * them to run sooner, but does not allow tons of sleepers to 6 * rip the spread apart. 7 */ 8 SCHED_FEAT(FAIR_SLEEPERS, false) 9 SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true) 10 11 /* 12 * Using the avg_vruntime, do the right thing and preserve lag across 13 * sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled. 14 */ 15 SCHED_FEAT(PLACE_LAG, true) 16 17 /* 18 * Prefer to schedule the task we woke last (assuming it failed 19 * wakeup-preemption), since its likely going to consume data we 20 * touched, increases cache locality. 21 */ 22 SCHED_FEAT(NEXT_BUDDY, false) 23 24 /* 25 * Prefer to schedule the task that ran last (when we did 26 * wake-preempt) as that likely will touch the same data, increases 27 * cache locality. 28 */ 29 SCHED_FEAT(LAST_BUDDY, true) 30 31 /* 32 * Consider buddies to be cache hot, decreases the likeliness of a 33 * cache buddy being migrated away, increases cache locality. 34 */ 35 SCHED_FEAT(CACHE_HOT_BUDDY, true) 36 37 /* 38 * Allow wakeup-time preemption of the current task: 39 */ 40 SCHED_FEAT(WAKEUP_PREEMPTION, true) 41 42 SCHED_FEAT(HRTICK, false) 43 SCHED_FEAT(HRTICK_DL, false) 44 SCHED_FEAT(DOUBLE_TICK, false) 45 46 /* 47 * Decrement CPU capacity based on time not spent running tasks 48 */ 49 SCHED_FEAT(NONTASK_CAPACITY, true) 50 51 #ifdef CONFIG_PREEMPT_RT 52 SCHED_FEAT(TTWU_QUEUE, false) 53 #else 54 55 /* 56 * Queue remote wakeups on the target CPU and process them 57 * using the scheduler IPI. Reduces rq->lock contention/bounces. 58 */ 59 SCHED_FEAT(TTWU_QUEUE, true) 60 #endif 61 62 /* 63 * When doing wakeups, attempt to limit superfluous scans of the LLC domain. 64 */ 65 SCHED_FEAT(SIS_PROP, false) 66 SCHED_FEAT(SIS_UTIL, true) 67 68 /* 69 * Issue a WARN when we do multiple update_rq_clock() calls 70 * in a single rq->lock section. Default disabled because the 71 * annotations are not complete. 72 */ 73 SCHED_FEAT(WARN_DOUBLE_CLOCK, false) 74 75 #ifdef HAVE_RT_PUSH_IPI 76 /* 77 * In order to avoid a thundering herd attack of CPUs that are 78 * lowering their priorities at the same time, and there being 79 * a single CPU that has an RT task that can migrate and is waiting 80 * to run, where the other CPUs will try to take that CPUs 81 * rq lock and possibly create a large contention, sending an 82 * IPI to that CPU and let that CPU push the RT task to where 83 * it should go may be a better scenario. 84 */ 85 SCHED_FEAT(RT_PUSH_IPI, true) 86 #endif 87 88 SCHED_FEAT(RT_RUNTIME_SHARE, false) 89 SCHED_FEAT(LB_MIN, false) 90 SCHED_FEAT(ATTACH_AGE_LOAD, true) 91 92 SCHED_FEAT(WA_IDLE, true) 93 SCHED_FEAT(WA_WEIGHT, true) 94 SCHED_FEAT(WA_BIAS, true) 95 96 /* 97 * UtilEstimation. Use estimated CPU utilization. 98 */ 99 SCHED_FEAT(UTIL_EST, true) 100 SCHED_FEAT(UTIL_EST_FASTUP, true) 101 102 SCHED_FEAT(LATENCY_WARN, false) 103 104 SCHED_FEAT(ALT_PERIOD, true) 105 SCHED_FEAT(BASE_SLICE, true) 106