Messages in this thread | | | From | Joel Fernandes <> | Date | Fri, 5 Nov 2021 19:05:41 -0400 | Subject | Re: RT_GROUP_SCHED throttling blocks unthrottled RT tasks? |
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On Fri, Nov 5, 2021 at 7:04 PM Joel Fernandes <joelaf@google.com> wrote: > > On Fri, Nov 5, 2021 at 1:44 PM Doug Anderson <dianders@chromium.org> wrote: > [..] > > > > > > I tried gathering some tracing. One bit that might (?) be relevant: > > > > cros_ec_spi_hig-179 [000] d.h5 1495.305919: sched_waking: > > comm=kworker/4:2 pid=5232 prio=120 target_cpu=004 > > cros_ec_spi_hig-179 [000] d.h6 1495.305926: sched_wakeup: > > comm=kworker/4:2 pid=5232 prio=120 target_cpu=004 > > <idle>-0 [001] d.H5 1495.309113: sched_waking: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > <idle>-0 [001] d.H6 1495.309119: sched_wakeup: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > cros_ec_spi_hig-179 [000] d.h5 1495.309336: sched_waking: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > cros_ec_spi_hig-179 [000] d.h6 1495.309341: sched_wakeup: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > <idle>-0 [001] d.H5 1495.312137: sched_waking: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > <idle>-0 [001] d.H6 1495.312142: sched_wakeup: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > cros_ec_spi_hig-179 [000] d.h5 1495.312859: sched_waking: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > cros_ec_spi_hig-179 [000] d.h6 1495.312870: sched_wakeup: > > comm=sugov:6 pid=2658 prio=-1 target_cpu=006 > > > > My best guess is that there's some bug in the scheduler where it just > > loops constantly picking an unthrottled RT task but then incorrectly > > decides that it's throttled and thus doesn't run it. > > Thanks for posting this. Tricky bit indeed. I was wondering if the > issue is here: > https://elixir.bootlin.com/linux/latest/source/kernel/sched/rt.c#L1031
Errm, I meant Line 1060 in rt.c https://elixir.bootlin.com/linux/latest/source/kernel/sched/rt.c#L1060
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