diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2007-09-05 14:32:49 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-09-05 14:32:49 +0200 |
| commit | 1169783085adb9ac969d21103a6885e8435f7ed3 (patch) | |
| tree | 8d5313ef18ba821436aa838cb6f03f065049ef21 /kernel | |
| parent | 4a55b45036a677fac43fe81ddf7fdcd007aaaee7 (diff) | |
sched: fix ideal_runtime calculations for reniced tasks
fix ideal_runtime:
- do not scale it using niced_granularity()
it is against sum_exec_delta, so its wall-time, not fair-time.
- move the whole check into __check_preempt_curr_fair()
so that wakeup preemption can also benefit from the new logic.
this also results in code size reduction:
text data bss dec hex filename
13391 228 1204 14823 39e7 sched.o.before
13369 228 1204 14801 39d1 sched.o.after
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched_fair.c | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 2d01bbc2d04..892616bf2c7 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -678,11 +678,31 @@ __check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, struct sched_entity *curr, unsigned long granularity) { s64 __delta = curr->fair_key - se->fair_key; + unsigned long ideal_runtime, delta_exec; + + /* + * ideal_runtime is compared against sum_exec_runtime, which is + * walltime, hence do not scale. + */ + ideal_runtime = max(sysctl_sched_latency / cfs_rq->nr_running, + (unsigned long)sysctl_sched_min_granularity); + + /* + * If we executed more than what the latency constraint suggests, + * reduce the rescheduling granularity. This way the total latency + * of how much a task is not scheduled converges to + * sysctl_sched_latency: + */ + delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; + if (delta_exec > ideal_runtime) + granularity = 0; /* * Take scheduling granularity into account - do not * preempt the current task unless the best task has * a larger than sched_granularity fairness advantage: + * + * scale granularity as key space is in fair_clock. */ if (__delta > niced_granularity(curr, granularity)) resched_task(rq_of(cfs_rq)->curr); @@ -731,7 +751,6 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) { - unsigned long gran, ideal_runtime, delta_exec; struct sched_entity *next; /* @@ -748,21 +767,8 @@ static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) if (next == curr) return; - gran = sched_granularity(cfs_rq); - ideal_runtime = niced_granularity(curr, - max(sysctl_sched_latency / cfs_rq->nr_running, - (unsigned long)sysctl_sched_min_granularity)); - /* - * If we executed more than what the latency constraint suggests, - * reduce the rescheduling granularity. This way the total latency - * of how much a task is not scheduled converges to - * sysctl_sched_latency: - */ - delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; - if (delta_exec > ideal_runtime) - gran = 0; - - __check_preempt_curr_fair(cfs_rq, next, curr, gran); + __check_preempt_curr_fair(cfs_rq, next, curr, + sched_granularity(cfs_rq)); } /************************************************** |