RE: [PATCH 0/4] sched: Various reweight_entity() fixes

["Doug Smythies" <dsmythies@telus.net>]

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On 2026.02.10 10:09 K Prateek Nayak wrote:
> On 2/10/2026 9:11 PM, Doug Smythies wrote:
>> My test computer also hung under the heavy heavy load test,
>> albeit at a higher load than before.
>> There was no log information that I could find after the re-boot.
>
> Could you run the same scenario with PARANOID_AVG:
>
>    echo PARANOID_AVG > /sys/kernel/debug/sched/features
>
> and once you are past the point when the system would have usually
> hung, can check if the "sum_shifts" reported for cfs_rq in the
> debugfs have changed to some non-zero value:
>
>    grep "shift.*: [^0]$" /sys/kernel/debug/sched/debug
>
> I'm assuming this is the same "yes" x 12500 copies bomb that failed.
> Let me see if I can reproduce this on my setup by leaving it going
> overnight on a limited cpuset.
>
> Since you mentioned there is some bound to the number of copies when
> the hang is observed, can you please share your system details and
> the number of CPUs it has?

I tried several times with PARANOID_AVG during my original work
with what I am calling "V1" of Peter's patch set. That was last week.
I never got a non-zero value.

Today, with what I am calling "V3" of Peter's patch set, I was
not able to get past the NO_PARANOID_AVG conditions.
I also never saw a non-zero value while trying as the number
of tasks ramped up.

An updated tasks verses elapsed time graph is attached.

... Doug


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