blob: d5059fd761d9bf49aca78e830a4fe9330bd464c9 [file] [log] [blame]
Peter Zijlstrae26af0e2009-09-11 12:31:23 +02001/*
2 * Disregards a certain amount of sleep time (sched_latency_ns) and
3 * considers the task to be running during that period. This gives it
4 * a service deficit on wakeup, allowing it to run sooner.
5 */
Ingo Molnar51e03042009-09-16 08:54:45 +02006SCHED_FEAT(FAIR_SLEEPERS, 1)
7
8/*
9 * Only give sleepers 50% of their service deficit. This allows
10 * them to run sooner, but does not allow tons of sleepers to
11 * rip the spread apart.
12 */
13SCHED_FEAT(GENTLE_FAIR_SLEEPERS, 1)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020014
15/*
16 * By not normalizing the sleep time, heavy tasks get an effective
17 * longer period, and lighter task an effective shorter period they
18 * are considered running.
19 */
Peter Zijlstrae52fb7c2009-01-14 12:39:19 +010020SCHED_FEAT(NORMALIZED_SLEEPER, 0)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020021
22/*
23 * Place new tasks ahead so that they do not starve already running
24 * tasks
25 */
Peter Zijlstraf00b45c2008-04-19 19:45:00 +020026SCHED_FEAT(START_DEBIT, 1)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020027
28/*
29 * Should wakeups try to preempt running tasks.
30 */
31SCHED_FEAT(WAKEUP_PREEMPT, 1)
32
33/*
34 * Compute wakeup_gran based on task behaviour, clipped to
35 * [0, sched_wakeup_gran_ns]
36 */
37SCHED_FEAT(ADAPTIVE_GRAN, 1)
38
39/*
40 * When converting the wakeup granularity to virtual time, do it such
41 * that heavier tasks preempting a lighter task have an edge.
42 */
43SCHED_FEAT(ASYM_GRAN, 1)
44
45/*
46 * Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
47 */
48SCHED_FEAT(WAKEUP_SYNC, 0)
49
50/*
51 * Wakeup preempt based on task behaviour. Tasks that do not overlap
52 * don't get preempted.
53 */
54SCHED_FEAT(WAKEUP_OVERLAP, 0)
55
56/*
57 * Use the SYNC wakeup hint, pipes and the likes use this to indicate
58 * the remote end is likely to consume the data we just wrote, and
59 * therefore has cache benefit from being placed on the same cpu, see
60 * also AFFINE_WAKEUPS.
61 */
Peter Zijlstraf00b45c2008-04-19 19:45:00 +020062SCHED_FEAT(SYNC_WAKEUPS, 1)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020063
64/*
65 * Based on load and program behaviour, see if it makes sense to place
66 * a newly woken task on the same cpu as the task that woke it --
67 * improve cache locality. Typically used with SYNC wakeups as
68 * generated by pipes and the like, see also SYNC_WAKEUPS.
69 */
70SCHED_FEAT(AFFINE_WAKEUPS, 1)
71
72/*
Peter Zijlstrae69b0f12009-09-15 19:38:52 +020073 * Weaken SYNC hint based on overlap
74 */
75SCHED_FEAT(SYNC_LESS, 1)
76
77/*
78 * Add SYNC hint based on overlap
79 */
80SCHED_FEAT(SYNC_MORE, 0)
81
82/*
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020083 * Prefer to schedule the task we woke last (assuming it failed
84 * wakeup-preemption), since its likely going to consume data we
85 * touched, increases cache locality.
86 */
Mike Galbraith0ec9fab2009-09-15 15:07:03 +020087SCHED_FEAT(NEXT_BUDDY, 0)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +020088
89/*
90 * Prefer to schedule the task that ran last (when we did
91 * wake-preempt) as that likely will touch the same data, increases
92 * cache locality.
93 */
94SCHED_FEAT(LAST_BUDDY, 1)
95
96/*
97 * Consider buddies to be cache hot, decreases the likelyness of a
98 * cache buddy being migrated away, increases cache locality.
99 */
100SCHED_FEAT(CACHE_HOT_BUDDY, 1)
101
Peter Zijlstra8e6598af2009-09-03 13:20:03 +0200102/*
103 * Use arch dependent cpu power functions
104 */
105SCHED_FEAT(ARCH_POWER, 0)
106
Ingo Molnar0c4b83d2008-10-20 14:27:43 +0200107SCHED_FEAT(HRTICK, 0)
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200108SCHED_FEAT(DOUBLE_TICK, 0)
Peter Zijlstraefc2dea2008-08-20 12:44:55 +0200109SCHED_FEAT(LB_BIAS, 1)
Peter Zijlstra3b640892009-09-16 13:44:33 +0200110SCHED_FEAT(LB_SHARES_UPDATE, 1)
Peter Zijlstraf5bfb7d2008-06-27 13:41:39 +0200111SCHED_FEAT(ASYM_EFF_LOAD, 1)
Peter Zijlstrae26af0e2009-09-11 12:31:23 +0200112
113/*
114 * Spin-wait on mutex acquisition when the mutex owner is running on
115 * another cpu -- assumes that when the owner is running, it will soon
116 * release the lock. Decreases scheduling overhead.
117 */
Peter Zijlstra0d66bf62009-01-12 14:01:47 +0100118SCHED_FEAT(OWNER_SPIN, 1)