LXR linux/kernel/sched

   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, 1)
   7
   8/*
   9 * Place new tasks ahead so that they do not starve already running
  10 * tasks
  11 */
  12SCHED_FEAT(START_DEBIT, 1)
  13
  14/*
  15 * Should wakeups try to preempt running tasks.
  16 */
  17SCHED_FEAT(WAKEUP_PREEMPT, 1)
  18
  19/*
  20 * Based on load and program behaviour, see if it makes sense to place
  21 * a newly woken task on the same cpu as the task that woke it --
  22 * improve cache locality. Typically used with SYNC wakeups as
  23 * generated by pipes and the like, see also SYNC_WAKEUPS.
  24 */
  25SCHED_FEAT(AFFINE_WAKEUPS, 1)
  26
  27/*
  28 * Prefer to schedule the task we woke last (assuming it failed
  29 * wakeup-preemption), since its likely going to consume data we
  30 * touched, increases cache locality.
  31 */
  32SCHED_FEAT(NEXT_BUDDY, 0)
  33
  34/*
  35 * Prefer to schedule the task that ran last (when we did
  36 * wake-preempt) as that likely will touch the same data, increases
  37 * cache locality.
  38 */
  39SCHED_FEAT(LAST_BUDDY, 1)
  40
  41/*
  42 * Consider buddies to be cache hot, decreases the likelyness of a
  43 * cache buddy being migrated away, increases cache locality.
  44 */
  45SCHED_FEAT(CACHE_HOT_BUDDY, 1)
  46
  47/*
  48 * Use arch dependent cpu power functions
  49 */
  50SCHED_FEAT(ARCH_POWER, 0)
  51
  52SCHED_FEAT(HRTICK, 0)
  53SCHED_FEAT(DOUBLE_TICK, 0)
  54SCHED_FEAT(LB_BIAS, 1)
  55
  56/*
  57 * Spin-wait on mutex acquisition when the mutex owner is running on
  58 * another cpu -- assumes that when the owner is running, it will soon
  59 * release the lock. Decreases scheduling overhead.
  60 */
  61SCHED_FEAT(OWNER_SPIN, 1)
  62
  63/*
  64 * Decrement CPU power based on irq activity
  65 */
  66SCHED_FEAT(NONIRQ_POWER, 1)
  67