sched: adaptive scheduler granularity

Instead of specifying the preemption granularity, specify the wanted
latency. By fixing the granlarity to a constany the wakeup latency
it a function of the number of running tasks on the rq.

Invert this relation.

sysctl_sched_granularity becomes a minimum for the dynamic granularity
computed from the new sysctl_sched_latency.

Then use this latency to do more intelligent granularity decisions: if
there are fewer tasks running then we can schedule coarser. This helps
performance while still always keeping the latency target.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2007-08-25 18:41:53 +02:00
committed by Ingo Molnar
parent 1fc84aaae3
commit 218050855e
4 changed files with 86 additions and 17 deletions

View File

@@ -1399,6 +1399,7 @@ static inline void idle_task_exit(void) {}
extern void sched_idle_next(void);
extern unsigned int sysctl_sched_latency;
extern unsigned int sysctl_sched_granularity;
extern unsigned int sysctl_sched_wakeup_granularity;
extern unsigned int sysctl_sched_batch_wakeup_granularity;