Messages in this thread | | | Subject | Re: [PATCH v4 08/10] sched/fair: Steal work from an overloaded CPU when CPU goes idle | From | Valentin Schneider <> | Date | Fri, 7 Dec 2018 20:21:28 +0000 |
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Hi Steve,
On 06/12/2018 21:28, Steve Sistare wrote: [...] > @@ -6778,20 +6791,22 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ > update_misfit_status(NULL, rq); > > /* > - * We must set idle_stamp _before_ calling idle_balance(), such that we > - * measure the duration of idle_balance() as idle time. > + * We must set idle_stamp _before_ calling try_steal() or > + * idle_balance(), such that we measure the duration as idle time. > */ > rq_idle_stamp_update(rq); >
idle_balance() has a
/* * Do not pull tasks towards !active CPUs... */ if (!cpu_active(this_cpu)) return 0;
check which we probably want for stealing too, so we could hoist it up here to cover both idle_balance() and try_steal().
> new_tasks = idle_balance(rq, rf); > + if (new_tasks == 0) > + new_tasks = try_steal(rq, rf); > > if (new_tasks) > rq_idle_stamp_clear(rq); > > /* > - * Because idle_balance() releases (and re-acquires) rq->lock, it is > - * possible for any higher priority task to appear. In that case we > - * must re-start the pick_next_entity() loop. > + * Because try_steal() and idle_balance() release (and re-acquire) > + * rq->lock, it is possible for any higher priority task to appear. > + * In that case we must re-start the pick_next_entity() loop. > */ > if (new_tasks < 0) > return RETRY_TASK; [...]
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