sched: introduce SCHED_FEAT_SYNC_WAKEUPS, turn it off

turn off sync wakeups by default. They are not needed anymore - the
buddy logic should be smart enough to keep the system from
overscheduling.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-03-16 20:03:22 +01:00
parent 0bbd3336ee
commit b85d066726

View file

@ -627,6 +627,7 @@ enum {
SCHED_FEAT_START_DEBIT = 4,
SCHED_FEAT_HRTICK = 8,
SCHED_FEAT_DOUBLE_TICK = 16,
SCHED_FEAT_SYNC_WAKEUPS = 32,
};
const_debug unsigned int sysctl_sched_features =
@ -634,7 +635,8 @@ const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_WAKEUP_PREEMPT * 1 |
SCHED_FEAT_START_DEBIT * 1 |
SCHED_FEAT_HRTICK * 1 |
SCHED_FEAT_DOUBLE_TICK * 0;
SCHED_FEAT_DOUBLE_TICK * 0 |
SCHED_FEAT_SYNC_WAKEUPS * 0;
#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
@ -1916,6 +1918,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
long old_state;
struct rq *rq;
if (!sched_feat(SYNC_WAKEUPS))
sync = 0;
smp_wmb();
rq = task_rq_lock(p, &flags);
old_state = p->state;