tree c7517529ec199d3d9936b4049880a820534d2703
parent 6f3d09291b4982991680b61763b2541e53e2a95f
author Ingo Molnar <mingo@elte.hu> 1205887320 +0100
committer Ingo Molnar <mingo@elte.hu> 1205897273 +0100

sched: improve affine wakeups

improve affine wakeups. Maintain the 'overlap' metric based on CFS's
sum_exec_runtime - which means the amount of time a task executes
after it wakes up some other task.

Use the 'overlap' for the wakeup decisions: if the 'overlap' is short,
it means there's strong workload coupling between this task and the
woken up task. If the 'overlap' is large then the workload is decoupled
and the scheduler will move them to separate CPUs more easily.

( Also slightly move the preempt_check within try_to_wake_up() - this has
  no effect on functionality but allows 'early wakeups' (for still-on-rq
  tasks) to be correctly accounted as well.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>