On 02/09/2016 07:09 PM, Rafael J. Wysocki wrote: >>> >> I think additional hooks such as enqueue/dequeue would be needed in >>> >> RT/DL. The task tick callbacks will only run if a task in that class is >>> >> executing at the time of the tick. There could be intermittent RT/DL >>> >> task activity in a frequency domain (the only task activity there, no >>> >> CFS tasks) that doesn't happen to overlap the tick. Worst case the task >>> >> activity could be periodic in such a way that it never overlaps the tick >>> >> and the update is never made. >> > >> > So if I'm reading this correctly, it would be better to put the hooks >> > into update_curr_rt/dl()?
That should AFAICS be sufficient to avoid stalling. It may be more than is required as that covers more than just enqueue/dequeue but I'm not sure offhand. > > If done this way, I guess we may pass rq_clock_task(rq) as the time > arg to cpufreq_update_util() from there and then the cpu_lock() call > I've added to this prototype won't be necessary any more. Is it rq_clock_task() or rq_clock()? The former can omit irq time so may gradually fall behind wall clock time, delaying callbacks in cpufreq. thanks, Steve
