Re: WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453

[Dietmar Eggemann <dietmar.eggemann@arm.com>]

On 29/07/2021 14:36, Bruno Goncalves wrote:
> On Wed, Jul 28, 2021 at 5:55 PM Dietmar Eggemann
> <dietmar.eggemann@arm.com> wrote:
>>
>> On 28/07/2021 15:11, Bruno Goncalves wrote:

[...]

>> Can't reproduce it on my Juno (arm64) (slow-switching (scpi-cpufreq
>> driver)).
> 
> We seem to be able to reproduce this only on Ampere Altra machines,
> specifically on mtjade and mtsnow cpus.
> 
> # cpupower frequency-info
> analyzing CPU 0:
>   driver: cppc_cpufreq
>   CPUs which run at the same hardware frequency: 0
>   CPUs which need to have their frequency coordinated by software: 0
>   maximum transition latency:  Cannot determine or is not supported.
>   hardware limits: 1000 MHz - 2.80 GHz
>   available cpufreq governors: conservative ondemand userspace
> powersave performance schedutil
>   current policy: frequency should be within 2.00 GHz and 2.80 GHz.
>                   The governor "schedutil" may decide which speed to use
>                   within this range.
>   current CPU frequency: 1.55 GHz (asserted by call to hardware)
> 
> # ps -eTo comm,pid,pri,class | grep sugov
> sugov:0            1082 140 DLN
> sugov:1            1085 140 DLN
> ...
> sugov:78           1319 140 DLN
> sugov:79           1320 140 DLN

Thanks! In the meantime I got access to an Ampere Altra so I can try
5.14.0-rc1 later today.