On 31 May 2016 at 14:39, Peter Zijlstra <pet...@infradead.org> wrote: > On Tue, May 31, 2016 at 02:33:45PM +0200, Vincent Guittot wrote: > >> The sched_avg of a task is not used anymore in copy_process with >> yuyang's patchset. To be fully correct, we still have a >> p->se.avg.last_update_time = 0 in cpu_cgroup_fork but this is just the >> side effect of factoring cpu_group_fork and cpu_group_move in >> sched_move_task and it will be overwritten by >> init_entity_runnable_average before being used. > > Yeah, but why? Why does init_entity_runnable_average() live in > wake_up_new_task()? That doesn't seem to make sense.
I don't really know. I would say that it can make sense now that the init of sched_avg is split it in 2 parts: post_init_entity_util_avg has to be done after set_task_cpu in wake_up_new_task > > Also note that vruntime_normalized() (ab)uses !se->sum_exec_runtime to > detect the new task state. > >> Now, cpu_cgroup_fork() only sets task group and cfs_rq of the forked task >> >> copy_process >> sched_fork >> ... >> cgroup_post_fork >> ss->fork() := cpu_cgroup_fork() which only set task group and >> cfs_rq of the sched_entity of the task >> >> wake_up_new_task >> init_entity_runnable_average >> activate_task >> enqueue_task >> attach_task > >
