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>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 11d8e9a..3625fca 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -929,6 +929,9 @@
u64 vruntime;
u64 prev_sum_exec_runtime;
+ u64 last_wakeup;
+ u64 avg_overlap;
+
#ifdef CONFIG_SCHEDSTATS
u64 wait_start;
u64 wait_max;