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kernel/sched_features.h 1.86 KB
e26af0e8b   Peter Zijlstra   sched: Add come c...
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  /*
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   * Only give sleepers 50% of their service deficit. This allows
   * them to run sooner, but does not allow tons of sleepers to
   * rip the spread apart.
   */
  SCHED_FEAT(GENTLE_FAIR_SLEEPERS, 1)
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  /*
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   * Place new tasks ahead so that they do not starve already running
   * tasks
   */
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  SCHED_FEAT(START_DEBIT, 1)
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  /*
   * Should wakeups try to preempt running tasks.
   */
  SCHED_FEAT(WAKEUP_PREEMPT, 1)
  
  /*
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   * Based on load and program behaviour, see if it makes sense to place
   * a newly woken task on the same cpu as the task that woke it --
   * improve cache locality. Typically used with SYNC wakeups as
   * generated by pipes and the like, see also SYNC_WAKEUPS.
   */
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  SCHED_FEAT(AFFINE_WAKEUPS, 1)
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  /*
   * Prefer to schedule the task we woke last (assuming it failed
   * wakeup-preemption), since its likely going to consume data we
   * touched, increases cache locality.
   */
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  SCHED_FEAT(NEXT_BUDDY, 0)
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  /*
   * Prefer to schedule the task that ran last (when we did
   * wake-preempt) as that likely will touch the same data, increases
   * cache locality.
   */
  SCHED_FEAT(LAST_BUDDY, 1)
  
  /*
   * Consider buddies to be cache hot, decreases the likelyness of a
   * cache buddy being migrated away, increases cache locality.
   */
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  SCHED_FEAT(CACHE_HOT_BUDDY, 1)
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  /*
   * Use arch dependent cpu power functions
   */
  SCHED_FEAT(ARCH_POWER, 0)
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  SCHED_FEAT(HRTICK, 0)
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  SCHED_FEAT(DOUBLE_TICK, 0)
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  SCHED_FEAT(LB_BIAS, 1)
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  /*
   * Spin-wait on mutex acquisition when the mutex owner is running on
   * another cpu -- assumes that when the owner is running, it will soon
   * release the lock. Decreases scheduling overhead.
   */
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  SCHED_FEAT(OWNER_SPIN, 1)
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  /*
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   * Decrement CPU power based on time not spent running tasks
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   */
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  SCHED_FEAT(NONTASK_POWER, 1)
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  /*
   * Queue remote wakeups on the target CPU and process them
   * using the scheduler IPI. Reduces rq->lock contention/bounces.
   */
  SCHED_FEAT(TTWU_QUEUE, 1)
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  SCHED_FEAT(FORCE_SD_OVERLAP, 0)