| 1 | /* |
| 2 | * Disregards a certain amount of sleep time (sched_latency_ns) and |
| 3 | * considers the task to be running during that period. This gives it |
| 4 | * a service deficit on wakeup, allowing it to run sooner. |
| 5 | */ |
| 6 | SCHED_FEAT(NEW_FAIR_SLEEPERS, 0) |
| 7 | |
| 8 | /* |
| 9 | * By not normalizing the sleep time, heavy tasks get an effective |
| 10 | * longer period, and lighter task an effective shorter period they |
| 11 | * are considered running. |
| 12 | */ |
| 13 | SCHED_FEAT(NORMALIZED_SLEEPER, 0) |
| 14 | |
| 15 | /* |
| 16 | * Place new tasks ahead so that they do not starve already running |
| 17 | * tasks |
| 18 | */ |
| 19 | SCHED_FEAT(START_DEBIT, 1) |
| 20 | |
| 21 | /* |
| 22 | * Should wakeups try to preempt running tasks. |
| 23 | */ |
| 24 | SCHED_FEAT(WAKEUP_PREEMPT, 1) |
| 25 | |
| 26 | /* |
| 27 | * Compute wakeup_gran based on task behaviour, clipped to |
| 28 | * [0, sched_wakeup_gran_ns] |
| 29 | */ |
| 30 | SCHED_FEAT(ADAPTIVE_GRAN, 1) |
| 31 | |
| 32 | /* |
| 33 | * When converting the wakeup granularity to virtual time, do it such |
| 34 | * that heavier tasks preempting a lighter task have an edge. |
| 35 | */ |
| 36 | SCHED_FEAT(ASYM_GRAN, 1) |
| 37 | |
| 38 | /* |
| 39 | * Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS. |
| 40 | */ |
| 41 | SCHED_FEAT(WAKEUP_SYNC, 0) |
| 42 | |
| 43 | /* |
| 44 | * Wakeup preempt based on task behaviour. Tasks that do not overlap |
| 45 | * don't get preempted. |
| 46 | */ |
| 47 | SCHED_FEAT(WAKEUP_OVERLAP, 0) |
| 48 | |
| 49 | /* |
| 50 | * Use the SYNC wakeup hint, pipes and the likes use this to indicate |
| 51 | * the remote end is likely to consume the data we just wrote, and |
| 52 | * therefore has cache benefit from being placed on the same cpu, see |
| 53 | * also AFFINE_WAKEUPS. |
| 54 | */ |
| 55 | SCHED_FEAT(SYNC_WAKEUPS, 1) |
| 56 | |
| 57 | /* |
| 58 | * Based on load and program behaviour, see if it makes sense to place |
| 59 | * a newly woken task on the same cpu as the task that woke it -- |
| 60 | * improve cache locality. Typically used with SYNC wakeups as |
| 61 | * generated by pipes and the like, see also SYNC_WAKEUPS. |
| 62 | */ |
| 63 | SCHED_FEAT(AFFINE_WAKEUPS, 1) |
| 64 | |
| 65 | /* |
| 66 | * Prefer to schedule the task we woke last (assuming it failed |
| 67 | * wakeup-preemption), since its likely going to consume data we |
| 68 | * touched, increases cache locality. |
| 69 | */ |
| 70 | SCHED_FEAT(NEXT_BUDDY, 0) |
| 71 | |
| 72 | /* |
| 73 | * Prefer to schedule the task that ran last (when we did |
| 74 | * wake-preempt) as that likely will touch the same data, increases |
| 75 | * cache locality. |
| 76 | */ |
| 77 | SCHED_FEAT(LAST_BUDDY, 1) |
| 78 | |
| 79 | /* |
| 80 | * Consider buddies to be cache hot, decreases the likelyness of a |
| 81 | * cache buddy being migrated away, increases cache locality. |
| 82 | */ |
| 83 | SCHED_FEAT(CACHE_HOT_BUDDY, 1) |
| 84 | |
| 85 | SCHED_FEAT(HRTICK, 0) |
| 86 | SCHED_FEAT(DOUBLE_TICK, 0) |
| 87 | SCHED_FEAT(LB_BIAS, 1) |
| 88 | SCHED_FEAT(LB_WAKEUP_UPDATE, 1) |
| 89 | SCHED_FEAT(ASYM_EFF_LOAD, 1) |
| 90 | |
| 91 | /* |
| 92 | * Spin-wait on mutex acquisition when the mutex owner is running on |
| 93 | * another cpu -- assumes that when the owner is running, it will soon |
| 94 | * release the lock. Decreases scheduling overhead. |
| 95 | */ |
| 96 | SCHED_FEAT(OWNER_SPIN, 1) |