[net-next-2.6.git] / kernel / sched_features.h

/*
 * Disregards a certain amount of sleep time (sched_latency_ns) and
 * considers the task to be running during that period. This gives it
 * a service deficit on wakeup, allowing it to run sooner.
 */
SCHED_FEAT(NEW_FAIR_SLEEPERS, 0)

/*
 * By not normalizing the sleep time, heavy tasks get an effective
 * longer period, and lighter task an effective shorter period they
 * are considered running.
 */
SCHED_FEAT(NORMALIZED_SLEEPER, 0)

/*
 * Place new tasks ahead so that they do not starve already running
 * tasks
 */
SCHED_FEAT(START_DEBIT, 1)

/*
 * Should wakeups try to preempt running tasks.
 */
SCHED_FEAT(WAKEUP_PREEMPT, 1)

/*
 * Compute wakeup_gran based on task behaviour, clipped to
 *  [0, sched_wakeup_gran_ns]
 */
SCHED_FEAT(ADAPTIVE_GRAN, 1)

/*
 * When converting the wakeup granularity to virtual time, do it such
 * that heavier tasks preempting a lighter task have an edge.
 */
SCHED_FEAT(ASYM_GRAN, 1)

/*
 * Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
 */
SCHED_FEAT(WAKEUP_SYNC, 0)

/*
 * Wakeup preempt based on task behaviour. Tasks that do not overlap
 * don't get preempted.
 */
SCHED_FEAT(WAKEUP_OVERLAP, 0)

/*
 * Use the SYNC wakeup hint, pipes and the likes use this to indicate
 * the remote end is likely to consume the data we just wrote, and
 * therefore has cache benefit from being placed on the same cpu, see
 * also AFFINE_WAKEUPS.
 */
SCHED_FEAT(SYNC_WAKEUPS, 1)

/*
 * 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.
 */
SCHED_FEAT(AFFINE_WAKEUPS, 1)

/*
 * 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.
 */
SCHED_FEAT(NEXT_BUDDY, 0)

/*
 * 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.
 */
SCHED_FEAT(CACHE_HOT_BUDDY, 1)

SCHED_FEAT(HRTICK, 0)
SCHED_FEAT(DOUBLE_TICK, 0)
SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)

/*
 * 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.
 */
SCHED_FEAT(OWNER_SPIN, 1)
Commit	Line	Data
e26af0e8 PZ	1	/*
	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	*/
3f2aa307	6	SCHED_FEAT(NEW_FAIR_SLEEPERS, 0)
e26af0e8 PZ	7
	8	/*
	9	* By not normalizing the sleep time, heavy tasks get an effective
	10	* longer period, and lighter task an effective shorter period they
	11	* are considered running.
	12	*/
e52fb7c0	13	SCHED_FEAT(NORMALIZED_SLEEPER, 0)
e26af0e8 PZ	14
	15	/*
	16	* Place new tasks ahead so that they do not starve already running
	17	* tasks
	18	*/
f00b45c1	19	SCHED_FEAT(START_DEBIT, 1)
e26af0e8 PZ	20
	21	/*
	22	* Should wakeups try to preempt running tasks.
	23	*/
	24	SCHED_FEAT(WAKEUP_PREEMPT, 1)
	25
	26	/*
	27	* Compute wakeup_gran based on task behaviour, clipped to
	28	* [0, sched_wakeup_gran_ns]
	29	*/
	30	SCHED_FEAT(ADAPTIVE_GRAN, 1)
	31
	32	/*
	33	* When converting the wakeup granularity to virtual time, do it such
	34	* that heavier tasks preempting a lighter task have an edge.
	35	*/
	36	SCHED_FEAT(ASYM_GRAN, 1)
	37
	38	/*
	39	* Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
	40	*/
	41	SCHED_FEAT(WAKEUP_SYNC, 0)
	42
	43	/*
	44	* Wakeup preempt based on task behaviour. Tasks that do not overlap
	45	* don't get preempted.
	46	*/
	47	SCHED_FEAT(WAKEUP_OVERLAP, 0)
	48
	49	/*
	50	* Use the SYNC wakeup hint, pipes and the likes use this to indicate
	51	* the remote end is likely to consume the data we just wrote, and
	52	* therefore has cache benefit from being placed on the same cpu, see
	53	* also AFFINE_WAKEUPS.
	54	*/
	55	SCHED_FEAT(SYNC_WAKEUPS, 1)
	56
	57	/*
	58	* Based on load and program behaviour, see if it makes sense to place
	59	* a newly woken task on the same cpu as the task that woke it --
	60	* improve cache locality. Typically used with SYNC wakeups as
	61	* generated by pipes and the like, see also SYNC_WAKEUPS.
	62	*/
f00b45c1	63	SCHED_FEAT(AFFINE_WAKEUPS, 1)
e26af0e8 PZ	64
	65	/*
	66	* Prefer to schedule the task we woke last (assuming it failed
	67	* wakeup-preemption), since its likely going to consume data we
	68	* touched, increases cache locality.
	69	*/
0ec9fab3	70	SCHED_FEAT(NEXT_BUDDY, 0)
e26af0e8 PZ	71
	72	/*
	73	* Prefer to schedule the task that ran last (when we did
	74	* wake-preempt) as that likely will touch the same data, increases
	75	* cache locality.
	76	*/
	77	SCHED_FEAT(LAST_BUDDY, 1)
	78
	79	/*
	80	* Consider buddies to be cache hot, decreases the likelyness of a
	81	* cache buddy being migrated away, increases cache locality.
	82	*/
f00b45c1	83	SCHED_FEAT(CACHE_HOT_BUDDY, 1)
e26af0e8	84
0c4b83da	85	SCHED_FEAT(HRTICK, 0)
f00b45c1	86	SCHED_FEAT(DOUBLE_TICK, 0)
efc2dead	87	SCHED_FEAT(LB_BIAS, 1)
2398f2c6	88	SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
f5bfb7d9	89	SCHED_FEAT(ASYM_EFF_LOAD, 1)
e26af0e8 PZ	90
	91	/*
	92	* Spin-wait on mutex acquisition when the mutex owner is running on
	93	* another cpu -- assumes that when the owner is running, it will soon
	94	* release the lock. Decreases scheduling overhead.
	95	*/
0d66bf6d	96	SCHED_FEAT(OWNER_SPIN, 1)