| Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 2 | /* |
| Ingo Molnar | 51e0304 | 2009-09-16 08:54:45 +0200 | [diff] [blame] | 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 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 7 | SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 8 | |
| 9 | /* |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 10 | * Place new tasks ahead so that they do not starve already running |
| 11 | * tasks |
| 12 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 13 | SCHED_FEAT(START_DEBIT, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 14 | |
| 15 | /* |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 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 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 20 | SCHED_FEAT(NEXT_BUDDY, false) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 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 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 27 | SCHED_FEAT(LAST_BUDDY, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 28 | |
| 29 | /* |
| 30 | * Consider buddies to be cache hot, decreases the likelyness of a |
| 31 | * cache buddy being migrated away, increases cache locality. |
| 32 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 33 | SCHED_FEAT(CACHE_HOT_BUDDY, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 34 | |
| Peter Zijlstra | 8e6598a | 2009-09-03 13:20:03 +0200 | [diff] [blame] | 35 | /* |
| Ingo Molnar | 8ed92e5 | 2012-10-14 14:28:50 +0200 | [diff] [blame] | 36 | * Allow wakeup-time preemption of the current task: |
| 37 | */ |
| 38 | SCHED_FEAT(WAKEUP_PREEMPTION, true) |
| 39 | |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 40 | SCHED_FEAT(HRTICK, false) |
| 41 | SCHED_FEAT(DOUBLE_TICK, false) |
| Dietmar Eggemann | fdf5f315 | 2018-08-09 14:57:53 +0100 | [diff] [blame] | 42 | SCHED_FEAT(LB_BIAS, false) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 43 | |
| 44 | /* |
| Nicolas Pitre | 5d4dfdd | 2014-05-27 13:50:41 -0400 | [diff] [blame] | 45 | * Decrement CPU capacity based on time not spent running tasks |
| Venkatesh Pallipadi | aa48380 | 2010-10-04 17:03:22 -0700 | [diff] [blame] | 46 | */ |
| Nicolas Pitre | 5d4dfdd | 2014-05-27 13:50:41 -0400 | [diff] [blame] | 47 | SCHED_FEAT(NONTASK_CAPACITY, true) |
| Peter Zijlstra | 317f394 | 2011-04-05 17:23:58 +0200 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Queue remote wakeups on the target CPU and process them |
| 51 | * using the scheduler IPI. Reduces rq->lock contention/bounces. |
| 52 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 53 | SCHED_FEAT(TTWU_QUEUE, true) |
| Peter Zijlstra | e3589f6 | 2011-07-15 10:35:52 +0200 | [diff] [blame] | 54 | |
| Peter Zijlstra | 4c77b18 | 2017-03-01 11:24:35 +0100 | [diff] [blame] | 55 | /* |
| 56 | * When doing wakeups, attempt to limit superfluous scans of the LLC domain. |
| 57 | */ |
| 58 | SCHED_FEAT(SIS_AVG_CPU, false) |
| Peter Zijlstra | 1ad3aaf | 2017-05-17 12:53:50 +0200 | [diff] [blame] | 59 | SCHED_FEAT(SIS_PROP, true) |
| Peter Zijlstra | 4c77b18 | 2017-03-01 11:24:35 +0100 | [diff] [blame] | 60 | |
| Peter Zijlstra | 26ae58d | 2016-10-03 16:53:49 +0200 | [diff] [blame] | 61 | /* |
| 62 | * Issue a WARN when we do multiple update_rq_clock() calls |
| 63 | * in a single rq->lock section. Default disabled because the |
| 64 | * annotations are not complete. |
| 65 | */ |
| 66 | SCHED_FEAT(WARN_DOUBLE_CLOCK, false) |
| 67 | |
| Steven Rostedt | b6366f0 | 2015-03-18 14:49:46 -0400 | [diff] [blame] | 68 | #ifdef HAVE_RT_PUSH_IPI |
| 69 | /* |
| 70 | * In order to avoid a thundering herd attack of CPUs that are |
| 71 | * lowering their priorities at the same time, and there being |
| 72 | * a single CPU that has an RT task that can migrate and is waiting |
| 73 | * to run, where the other CPUs will try to take that CPUs |
| 74 | * rq lock and possibly create a large contention, sending an |
| 75 | * IPI to that CPU and let that CPU push the RT task to where |
| 76 | * it should go may be a better scenario. |
| 77 | */ |
| 78 | SCHED_FEAT(RT_PUSH_IPI, true) |
| 79 | #endif |
| 80 | |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 81 | SCHED_FEAT(RT_RUNTIME_SHARE, true) |
| Peter Zijlstra | eb95308 | 2012-04-17 13:38:40 +0200 | [diff] [blame] | 82 | SCHED_FEAT(LB_MIN, false) |
| Peter Zijlstra | a928051 | 2015-09-11 16:10:59 +0200 | [diff] [blame] | 83 | SCHED_FEAT(ATTACH_AGE_LOAD, true) |
| 84 | |
| Peter Zijlstra | d153b15 | 2017-09-27 11:35:30 +0200 | [diff] [blame] | 85 | SCHED_FEAT(WA_IDLE, true) |
| Peter Zijlstra | f2cdd9c | 2017-10-06 09:23:24 +0200 | [diff] [blame] | 86 | SCHED_FEAT(WA_WEIGHT, true) |
| 87 | SCHED_FEAT(WA_BIAS, true) |
| Patrick Bellasi | 7f65ea4 | 2018-03-09 09:52:42 +0000 | [diff] [blame] | 88 | |
| 89 | /* |
| 90 | * UtilEstimation. Use estimated CPU utilization. |
| 91 | */ |
| Patrick Bellasi | d519329 | 2018-03-09 09:52:45 +0000 | [diff] [blame] | 92 | SCHED_FEAT(UTIL_EST, true) |