Re: [Question] Sched: Severe scheduling latency (>10s) observed on kernel 6.12 with specific workload

[John Stultz]

On Tue, Apr 14, 2026 at 8:43 AM Dietmar Eggemann
<dietmar.eggemann@xxxxxxx> wrote:
>
> Just guessing ... does Android do more task
> reweights (set_load_weight(p, true)) ?
>

Possibly?

> on tip sched/core:
>
> [PATCH v2 0/7] sched: Various reweight_entity() fixes
>
> https://lore.kernel.org/r/20260219075840.162631716@xxxxxxxxxxxxx
>
> db4551e2ba34 - sched/fair: Use full weight to __calc_delta() (2026-02-23
> Peter Zijlstra)
>
> 101f3498b4bd - sched/fair: Revert 6d71a9c61604 ("sched/fair: Fix EEVDF
> entity placement bug causing scheduling lag") (2026-02-23 Peter
> Zijlstra) <-- !!!

Oh geeze! I missed that. The revert does resolve the latencies in this
case, and the description in that thread:
  https://lore.kernel.org/all/20260324100126.3502-1-willymontaz@xxxxxxxxx/

Sounds very similar.

Thank you for pointing this out!
-john