linux/kernel/sched/features.h
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   1/*
   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 */
   6SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
   7
   8/*
   9 * Place new tasks ahead so that they do not starve already running
  10 * tasks
  11 */
  12SCHED_FEAT(START_DEBIT, true)
  13
  14/*
  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 */
  20SCHED_FEAT(AFFINE_WAKEUPS, true)
  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 */
  27SCHED_FEAT(NEXT_BUDDY, false)
  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 */
  34SCHED_FEAT(LAST_BUDDY, true)
  35
  36/*
  37 * Consider buddies to be cache hot, decreases the likelyness of a
  38 * cache buddy being migrated away, increases cache locality.
  39 */
  40SCHED_FEAT(CACHE_HOT_BUDDY, true)
  41
  42/*
  43 * Use arch dependent cpu power functions
  44 */
  45SCHED_FEAT(ARCH_POWER, false)
  46
  47SCHED_FEAT(HRTICK, false)
  48SCHED_FEAT(DOUBLE_TICK, false)
  49SCHED_FEAT(LB_BIAS, true)
  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 */
  56SCHED_FEAT(OWNER_SPIN, true)
  57
  58/*
  59 * Decrement CPU power based on time not spent running tasks
  60 */
  61SCHED_FEAT(NONTASK_POWER, true)
  62
  63/*
  64 * Queue remote wakeups on the target CPU and process them
  65 * using the scheduler IPI. Reduces rq->lock contention/bounces.
  66 */
  67SCHED_FEAT(TTWU_QUEUE, true)
  68
  69SCHED_FEAT(FORCE_SD_OVERLAP, false)
  70SCHED_FEAT(RT_RUNTIME_SHARE, true)
  71SCHED_FEAT(LB_MIN, false)
  72
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