blob: 1b3c8189b28656d2644a714ff60ceab7d015d97b [file] [log] [blame]
Peter Zijlstrae26af0e2009-09-11 12:31:23 +02001/*
Ingo Molnar51e03042009-09-16 08:54:45 +02002 * Only give sleepers 50% of their service deficit. This allows
3 * them to run sooner, but does not allow tons of sleepers to
4 * rip the spread apart.
5 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +02006SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +02007
8/*
Peter Zijlstrae26af0e2009-09-11 12:31:23 +02009 * Place new tasks ahead so that they do not starve already running
10 * tasks
11 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020012SCHED_FEAT(START_DEBIT, true)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020013
14/*
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020015 * Prefer to schedule the task we woke last (assuming it failed
16 * wakeup-preemption), since its likely going to consume data we
17 * touched, increases cache locality.
18 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020019SCHED_FEAT(NEXT_BUDDY, false)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020020
21/*
22 * Prefer to schedule the task that ran last (when we did
23 * wake-preempt) as that likely will touch the same data, increases
24 * cache locality.
25 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020026SCHED_FEAT(LAST_BUDDY, true)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020027
28/*
29 * Consider buddies to be cache hot, decreases the likelyness of a
30 * cache buddy being migrated away, increases cache locality.
31 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020032SCHED_FEAT(CACHE_HOT_BUDDY, true)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020033
Peter Zijlstra8e6598a2009-09-03 13:20:03 +020034/*
Ingo Molnar8ed92e52012-10-14 14:28:50 +020035 * Allow wakeup-time preemption of the current task:
36 */
37SCHED_FEAT(WAKEUP_PREEMPTION, true)
38
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020039SCHED_FEAT(HRTICK, false)
40SCHED_FEAT(DOUBLE_TICK, false)
41SCHED_FEAT(LB_BIAS, true)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020042
43/*
Nicolas Pitre5d4dfdd2014-05-27 13:50:41 -040044 * Decrement CPU capacity based on time not spent running tasks
Venkatesh Pallipadiaa483802010-10-04 17:03:22 -070045 */
Nicolas Pitre5d4dfdd2014-05-27 13:50:41 -040046SCHED_FEAT(NONTASK_CAPACITY, true)
Peter Zijlstra317f3942011-04-05 17:23:58 +020047
48/*
49 * Queue remote wakeups on the target CPU and process them
50 * using the scheduler IPI. Reduces rq->lock contention/bounces.
51 */
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020052SCHED_FEAT(TTWU_QUEUE, true)
Peter Zijlstrae3589f62011-07-15 10:35:52 +020053
Peter Zijlstra4e4a9eb2017-03-01 11:24:35 +010054/*
55 * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
56 */
57SCHED_FEAT(SIS_AVG_CPU, false)
58
Steven Rostedtb6366f02015-03-18 14:49:46 -040059#ifdef HAVE_RT_PUSH_IPI
60/*
61 * In order to avoid a thundering herd attack of CPUs that are
62 * lowering their priorities at the same time, and there being
63 * a single CPU that has an RT task that can migrate and is waiting
64 * to run, where the other CPUs will try to take that CPUs
65 * rq lock and possibly create a large contention, sending an
66 * IPI to that CPU and let that CPU push the RT task to where
67 * it should go may be a better scenario.
68 */
69SCHED_FEAT(RT_PUSH_IPI, true)
70#endif
71
Peter Zijlstraf8b6d1c2011-07-06 14:20:14 +020072SCHED_FEAT(FORCE_SD_OVERLAP, false)
73SCHED_FEAT(RT_RUNTIME_SHARE, true)
Peter Zijlstraeb953082012-04-17 13:38:40 +020074SCHED_FEAT(LB_MIN, false)
Peter Zijlstraa9280512015-09-11 16:10:59 +020075SCHED_FEAT(ATTACH_AGE_LOAD, true)
76