2009-09-11 12:31:23 +02:00
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/*
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* Disregards a certain amount of sleep time (sched_latency_ns) and
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* considers the task to be running during that period. This gives it
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* a service deficit on wakeup, allowing it to run sooner.
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*/
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2009-09-16 08:54:45 +02:00
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SCHED_FEAT(FAIR_SLEEPERS, 1)
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/*
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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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2009-09-11 12:31:23 +02:00
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/*
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* By not normalizing the sleep time, heavy tasks get an effective
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* longer period, and lighter task an effective shorter period they
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* are considered running.
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*/
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2009-01-14 12:39:19 +01:00
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SCHED_FEAT(NORMALIZED_SLEEPER, 0)
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2009-09-11 12:31:23 +02:00
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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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2008-04-19 19:45:00 +02:00
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SCHED_FEAT(START_DEBIT, 1)
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2009-09-11 12:31:23 +02:00
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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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* Compute wakeup_gran based on task behaviour, clipped to
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* [0, sched_wakeup_gran_ns]
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*/
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SCHED_FEAT(ADAPTIVE_GRAN, 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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* Wakeup preempt based on task behaviour. Tasks that do not overlap
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* don't get preempted.
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*/
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SCHED_FEAT(WAKEUP_OVERLAP, 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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2008-04-19 19:45:00 +02:00
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SCHED_FEAT(AFFINE_WAKEUPS, 1)
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2009-09-11 12:31:23 +02:00
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2009-09-15 19:38:52 +02:00
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/*
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* Weaken SYNC hint based on overlap
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*/
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SCHED_FEAT(SYNC_LESS, 1)
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/*
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* Add SYNC hint based on overlap
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*/
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SCHED_FEAT(SYNC_MORE, 0)
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2009-09-11 12:31:23 +02:00
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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: Improve latencies and throughput
Make the idle balancer more agressive, to improve a
x264 encoding workload provided by Jason Garrett-Glaser:
NEXT_BUDDY NO_LB_BIAS
encoded 600 frames, 252.82 fps, 22096.60 kb/s
encoded 600 frames, 250.69 fps, 22096.60 kb/s
encoded 600 frames, 245.76 fps, 22096.60 kb/s
NO_NEXT_BUDDY LB_BIAS
encoded 600 frames, 344.44 fps, 22096.60 kb/s
encoded 600 frames, 346.66 fps, 22096.60 kb/s
encoded 600 frames, 352.59 fps, 22096.60 kb/s
NO_NEXT_BUDDY NO_LB_BIAS
encoded 600 frames, 425.75 fps, 22096.60 kb/s
encoded 600 frames, 425.45 fps, 22096.60 kb/s
encoded 600 frames, 422.49 fps, 22096.60 kb/s
Peter pointed out that this is better done via newidle_idx,
not via LB_BIAS, newidle balancing should look for where
there is load _now_, not where there was load 2 ticks ago.
Worst-case latencies are improved as well as no buddies
means less vruntime spread. (as per prior lkml discussions)
This change improves kbuild-peak parallelism as well.
Reported-by: Jason Garrett-Glaser <darkshikari@gmail.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1253011667.9128.16.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15 15:07:03 +02:00
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SCHED_FEAT(NEXT_BUDDY, 0)
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2009-09-11 12:31:23 +02:00
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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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*/
|
2008-04-19 19:45:00 +02:00
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SCHED_FEAT(CACHE_HOT_BUDDY, 1)
|
2009-09-11 12:31:23 +02:00
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|
2009-09-03 13:20:03 +02:00
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|
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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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|
2008-10-20 14:27:43 +02:00
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SCHED_FEAT(HRTICK, 0)
|
2008-04-19 19:45:00 +02:00
|
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SCHED_FEAT(DOUBLE_TICK, 0)
|
2008-08-20 12:44:55 +02:00
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SCHED_FEAT(LB_BIAS, 1)
|
2008-06-27 13:41:35 +02:00
|
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SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
|
2008-06-27 13:41:39 +02:00
|
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SCHED_FEAT(ASYM_EFF_LOAD, 1)
|
2009-09-11 12:31:23 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* 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.
|
|
|
|
*/
|
2009-01-12 14:01:47 +01:00
|
|
|
SCHED_FEAT(OWNER_SPIN, 1)
|