| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 1 | /* |
| Ingo Molnar | 51e0304 | 2009-09-16 08:54:45 +0200 | [diff] [blame] | 2 | * 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 Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 6 | SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 7 | |
| 8 | /* |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 9 | * Place new tasks ahead so that they do not starve already running |
| 10 | * tasks |
| 11 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 12 | SCHED_FEAT(START_DEBIT, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 13 | |
| 14 | /* |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 15 | * Based on load and program behaviour, see if it makes sense to place |
| 16 | * a newly woken task on the same cpu as the task that woke it -- |
| 17 | * improve cache locality. Typically used with SYNC wakeups as |
| 18 | * generated by pipes and the like, see also SYNC_WAKEUPS. |
| 19 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 20 | SCHED_FEAT(AFFINE_WAKEUPS, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 21 | |
| 22 | /* |
| 23 | * Prefer to schedule the task we woke last (assuming it failed |
| 24 | * wakeup-preemption), since its likely going to consume data we |
| 25 | * touched, increases cache locality. |
| 26 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 27 | SCHED_FEAT(NEXT_BUDDY, false) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 28 | |
| 29 | /* |
| 30 | * Prefer to schedule the task that ran last (when we did |
| 31 | * wake-preempt) as that likely will touch the same data, increases |
| 32 | * cache locality. |
| 33 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 34 | SCHED_FEAT(LAST_BUDDY, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * Consider buddies to be cache hot, decreases the likelyness of a |
| 38 | * cache buddy being migrated away, increases cache locality. |
| 39 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 40 | SCHED_FEAT(CACHE_HOT_BUDDY, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 41 | |
| Peter Zijlstra | 8e6598a | 2009-09-03 13:20:03 +0200 | [diff] [blame] | 42 | /* |
| 43 | * Use arch dependent cpu power functions |
| 44 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 45 | SCHED_FEAT(ARCH_POWER, false) |
| Peter Zijlstra | 8e6598a | 2009-09-03 13:20:03 +0200 | [diff] [blame] | 46 | |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 47 | SCHED_FEAT(HRTICK, false) |
| 48 | SCHED_FEAT(DOUBLE_TICK, false) |
| 49 | SCHED_FEAT(LB_BIAS, true) |
| Peter Zijlstra | e26af0e | 2009-09-11 12:31:23 +0200 | [diff] [blame] | 50 | |
| 51 | /* |
| 52 | * Spin-wait on mutex acquisition when the mutex owner is running on |
| 53 | * another cpu -- assumes that when the owner is running, it will soon |
| 54 | * release the lock. Decreases scheduling overhead. |
| 55 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 56 | SCHED_FEAT(OWNER_SPIN, true) |
| Venkatesh Pallipadi | aa48380 | 2010-10-04 17:03:22 -0700 | [diff] [blame] | 57 | |
| 58 | /* |
| Glauber Costa | 095c0aa | 2011-07-11 15:28:18 -0400 | [diff] [blame] | 59 | * Decrement CPU power based on time not spent running tasks |
| Venkatesh Pallipadi | aa48380 | 2010-10-04 17:03:22 -0700 | [diff] [blame] | 60 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 61 | SCHED_FEAT(NONTASK_POWER, true) |
| Peter Zijlstra | 317f394 | 2011-04-05 17:23:58 +0200 | [diff] [blame] | 62 | |
| 63 | /* |
| 64 | * Queue remote wakeups on the target CPU and process them |
| 65 | * using the scheduler IPI. Reduces rq->lock contention/bounces. |
| 66 | */ |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 67 | SCHED_FEAT(TTWU_QUEUE, true) |
| Peter Zijlstra | e3589f6 | 2011-07-15 10:35:52 +0200 | [diff] [blame] | 68 | |
| Peter Zijlstra | f8b6d1c | 2011-07-06 14:20:14 +0200 | [diff] [blame] | 69 | SCHED_FEAT(FORCE_SD_OVERLAP, false) |
| 70 | SCHED_FEAT(RT_RUNTIME_SHARE, true) |