> On Aug 17, 2020, at 4:57 PM, Dietmar Eggemann <dietmar.eggem...@arm.com> > wrote: > > 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? Yes. :) > > 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) My tick is 1ms - 1000HZ, which seems reasonable for 600ms? :)
Thx. Regards, Jiang > >>>> ** 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
