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

[John Stultz]

On Thu, Apr 9, 2026 at 8:31 PM Xuewen Yan <xuewen.yan94@xxxxxxxxx> wrote:
> On Fri, Apr 10, 2026 at 5:39 AM John Stultz <jstultz@xxxxxxxxxx> wrote:
>>
> > So, with this config I think I may have reproduced it on a device
> > (using android16-6.12).  I've not quite seen 10+ seconds, but I have
> > seen >2second delays for kworker threads (though usually the max seems
> > to be around 600ms).
>
> Thanks for the detailed update! It’s great to hear that you’ve managed
> to reproduce the issue on a real device. Even though the latency is
> around 2 seconds (instead of 10+), that still significantly confirms
> the problem exists. The difference in magnitude might just be due to
> specific background load conditions.

So, I believe there is an issue in the android16-6.12 tree where some
changes from upstream, not in 6.12-stable were backported, and then
some fixes from 6.12-stable were reverted, and the mix of the two is
causing problems. I've tried to align the tree more closely to
6.12-stable and I'm seeing the results improve, so now its just a
matter of trying to de-tangle things in the android tree.

So, for the community folks: I don't think upstream or the -stable
tree is connected to what is being reported.

thanks
-john