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