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>
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4a55b45036
Коммит
1169783085
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@ -678,11 +678,31 @@ __check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
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struct sched_entity *curr, unsigned long granularity)
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struct sched_entity *curr, unsigned long granularity)
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{
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{
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s64 __delta = curr->fair_key - se->fair_key;
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s64 __delta = curr->fair_key - se->fair_key;
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unsigned long ideal_runtime, delta_exec;
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/*
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* ideal_runtime is compared against sum_exec_runtime, which is
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* walltime, hence do not scale.
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*/
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ideal_runtime = max(sysctl_sched_latency / cfs_rq->nr_running,
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(unsigned long)sysctl_sched_min_granularity);
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/*
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* If we executed more than what the latency constraint suggests,
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* reduce the rescheduling granularity. This way the total latency
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* of how much a task is not scheduled converges to
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* sysctl_sched_latency:
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*/
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delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
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if (delta_exec > ideal_runtime)
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granularity = 0;
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/*
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/*
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* Take scheduling granularity into account - do not
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* Take scheduling granularity into account - do not
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* preempt the current task unless the best task has
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* preempt the current task unless the best task has
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* a larger than sched_granularity fairness advantage:
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* a larger than sched_granularity fairness advantage:
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*
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* scale granularity as key space is in fair_clock.
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*/
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*/
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if (__delta > niced_granularity(curr, granularity))
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if (__delta > niced_granularity(curr, granularity))
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resched_task(rq_of(cfs_rq)->curr);
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resched_task(rq_of(cfs_rq)->curr);
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@ -731,7 +751,6 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
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static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
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static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
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{
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{
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unsigned long gran, ideal_runtime, delta_exec;
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struct sched_entity *next;
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struct sched_entity *next;
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/*
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/*
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@ -748,21 +767,8 @@ static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
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if (next == curr)
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if (next == curr)
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return;
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return;
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gran = sched_granularity(cfs_rq);
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__check_preempt_curr_fair(cfs_rq, next, curr,
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ideal_runtime = niced_granularity(curr,
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sched_granularity(cfs_rq));
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max(sysctl_sched_latency / cfs_rq->nr_running,
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(unsigned long)sysctl_sched_min_granularity));
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/*
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* If we executed more than what the latency constraint suggests,
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* reduce the rescheduling granularity. This way the total latency
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* of how much a task is not scheduled converges to
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* sysctl_sched_latency:
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*/
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delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
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if (delta_exec > ideal_runtime)
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gran = 0;
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__check_preempt_curr_fair(cfs_rq, next, curr, gran);
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}
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}
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/**************************************************
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/**************************************************
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