On 14/08/2020 01:55, benbjiang(蒋彪) wrote: > Hi, > >> On Aug 13, 2020, at 2:39 AM, Dietmar Eggemann <dietmar.eggem...@arm.com> >> wrote: >> >> On 12/08/2020 05:19, benbjiang(蒋彪) wrote: >>> Hi, >>> >>>> On Aug 11, 2020, at 11:54 PM, Dietmar Eggemann <dietmar.eggem...@arm.com> >>>> wrote: >>>> >>>> On 11/08/2020 02:41, benbjiang(蒋彪) wrote: >>>>> Hi, >>>>> >>>>>> On Aug 10, 2020, at 9:24 PM, Dietmar Eggemann <dietmar.eggem...@arm.com> >>>>>> wrote: >>>>>> >>>>>> On 06/08/2020 17:52, benbjiang(蒋彪) wrote: >>>>>>> Hi, >>>>>>> >>>>>>>> On Aug 6, 2020, at 9:29 PM, Dietmar Eggemann >>>>>>>> <dietmar.eggem...@arm.com> wrote: >>>>>>>> >>>>>>>> On 03/08/2020 13:26, benbjiang(蒋彪) wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>>> On Aug 3, 2020, at 4:16 PM, Dietmar Eggemann >>>>>>>>>> <dietmar.eggem...@arm.com> wrote: >>>>>>>>>> >>>>>>>>>> On 01/08/2020 04:32, Jiang Biao wrote: >>>>>>>>>>> From: Jiang Biao <benbji...@tencent.com>
[...] >>> ** 2normal+1idle: idle preempt normal every 600+ms ** >> >> During the 3.2s the 2 SCHED_OTHER tasks run, the SCHED_IDLE task is >> switched in only once, after ~2.5s. > Use your config with loop increased from 200 to 2000, to observe longer, > > <...>-37620 [002] d... 47950.446191: sched_switch: > prev_comm=task_other-1 prev_pid=37620 prev_prio=120 prev_state=S ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > <...>-37619 [002] d... 47955.687709: sched_switch: > prev_comm=task_other-0 prev_pid=37619 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > // The first preemption interval is 5.2s. > <...>-37620 [002] d... 47956.375716: sched_switch: > prev_comm=task_other-1 prev_pid=37620 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > <...>-37619 [002] d... 47957.060722: sched_switch: > prev_comm=task_other-0 prev_pid=37619 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > <...>-37620 [002] d... 47957.747728: sched_switch: > prev_comm=task_other-1 prev_pid=37620 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > <...>-37620 [002] d... 47958.423734: sched_switch: > prev_comm=task_other-1 prev_pid=37620 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > <...>-37620 [002] d... 47959.119740: sched_switch: > prev_comm=task_other-1 prev_pid=37620 prev_prio=120 prev_state=R ==> > next_comm=task_idle-2 next_pid=37621 next_prio=120 > // After the first preemption, the rest preemption intervals are all about > 600ms+. :) Are you sure about this? The math is telling me for the: idle task: (3 / (1024 + 1024 + 3))^(-1) * 4ms = 2735ms normal task: (1024 / (1024 + 1024 + 3))^(-1) * 4ms = 8ms (4ms - 250 Hz) >>> ** 3normal+idle: idle preempt normal every 1000+ms ** >> >> Ah, this was meant to be 3 SCHED_OTHER tasks only! To see the difference >> in behavior. > With 3 SCHED_OHTER tasks only, the SCHED_OHTER task is switched in > Every 27ms. normal task: (1024 / (1024 + 1024 + 1024))^(-1) * 4ms = 12ms >>> ** 2normal(nice 19)+1idle(nice 0): idle preempt normal every 30+ms ** >> >> During the 3.2s the 2 SCHED_OTHER tasks run, the SCHED_IDLE task is >> switched in every ~45ms. > That’s as what I expected. :) idle task: (3 / (15 + 15 + 3))^(-1) * 4ms = 44ms normal task: (15 / (15 + 15 + 3))^(-1) * 4ms = 9ms
