5ca9880c6f
Our preemption model relies too heavily on sleeper fairness to disable it without dire consequences. Remove the feature, and save a branch or two. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301520.6785.40.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/*
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* Only give sleepers 50% of their service deficit. This allows
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* them to run sooner, but does not allow tons of sleepers to
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* rip the spread apart.
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*/
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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
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* tasks
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*/
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SCHED_FEAT(START_DEBIT, 1)
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/*
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* Should wakeups try to preempt running tasks.
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*/
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SCHED_FEAT(WAKEUP_PREEMPT, 1)
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/*
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* When converting the wakeup granularity to virtual time, do it such
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* that heavier tasks preempting a lighter task have an edge.
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*/
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SCHED_FEAT(ASYM_GRAN, 1)
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/*
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* Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
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*/
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SCHED_FEAT(WAKEUP_SYNC, 0)
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/*
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* Use the SYNC wakeup hint, pipes and the likes use this to indicate
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* the remote end is likely to consume the data we just wrote, and
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* therefore has cache benefit from being placed on the same cpu, see
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* also AFFINE_WAKEUPS.
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*/
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SCHED_FEAT(SYNC_WAKEUPS, 1)
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/*
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* Based on load and program behaviour, see if it makes sense to place
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* a newly woken task on the same cpu as the task that woke it --
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* improve cache locality. Typically used with SYNC wakeups as
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* generated by pipes and the like, see also SYNC_WAKEUPS.
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*/
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SCHED_FEAT(AFFINE_WAKEUPS, 1)
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/*
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* Prefer to schedule the task we woke last (assuming it failed
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* wakeup-preemption), since its likely going to consume data we
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* touched, increases cache locality.
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*/
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SCHED_FEAT(NEXT_BUDDY, 0)
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/*
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* Prefer to schedule the task that ran last (when we did
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* wake-preempt) as that likely will touch the same data, increases
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* cache locality.
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*/
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SCHED_FEAT(LAST_BUDDY, 1)
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/*
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* Consider buddies to be cache hot, decreases the likelyness of a
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* cache buddy being migrated away, increases cache locality.
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*/
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SCHED_FEAT(CACHE_HOT_BUDDY, 1)
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/*
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* Use arch dependent cpu power functions
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*/
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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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SCHED_FEAT(LB_SHARES_UPDATE, 1)
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SCHED_FEAT(ASYM_EFF_LOAD, 1)
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/*
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* Spin-wait on mutex acquisition when the mutex owner is running on
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* another cpu -- assumes that when the owner is running, it will soon
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* release the lock. Decreases scheduling overhead.
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*/
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SCHED_FEAT(OWNER_SPIN, 1)
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