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For example, the try_to_wake_up(), update_rq_avg_idle() is >> called by >> >> the other CPUs. So enqueue_task() is a good place. > But put_prev_task_idle() is called by local CPU whenever it leaves > idle so instead of trying to catch all places that could make the CPU > leave idle it's better to use this single place. > And as you mentioned, put_prev_task_idle is only called by local CPU > whereas enqueue_task can be called by all CPUs creating useless > pressure in the variable. The rq->idle_stamp is set at sched_balance_newidle().  then we call update_rq_avg_idle() in put_prev_task_idle() right now. How can we update the rq->avg_idle? Thanks Huang Shijie >>