Hi Yuyang, On 12/13/2015 11:13 AM, Yuyang Du wrote: > Hi Steve, > > On Fri, Dec 11, 2015 at 06:01:45PM -0800, Steve Muckle wrote: >> In init_entity_runnable_average() the last_update_time is initialized to >> zero. The task is given max load and utilization as a pessimistic >> initial estimate. >> >> But if in wake_up_new_task() the task is placed on a CPU other than >> where it was created, __update_load_avg() will be called via >> set_task_cpu() -> migrate_task_rq_fair() -> remove_entity_load_avg(). >> >> Since last_update_time is zero the delta will be huge and the task's >> load will be entirely decayed away before it is enqueued at the >> destination CPU. > > Since the new task's last_update_time is equal to 0, it will not be decayed.
Can you point me to the code for that logic? I don't see anything that prevents the decay when a newly woken task is placed on a different CPU via the call chain I mentioned above. My testing also shows the load being decayed to zero. thanks Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
