On Wed, 23 Jun 2021 at 18:46, Sachin Sant <sach...@linux.vnet.ibm.com> wrote:
>
>
> > Ok. This becomes even more weird. Could you share your config file and more 
> > details about
> > you setup ?
> >
> > Have you applied the patch below ?
> > https://lore.kernel.org/lkml/20210621174330.11258-1-vincent.guit...@linaro.org/
> >
> > Regarding the load_avg warning, I can see possible problem during attach. 
> > Could you add
> > the patch below. The load_avg warning seems to happen during boot and 
> > sched_entity
> > creation.
> >
>
> Here is a summary of my testing.
>
> I have a POWER box with PowerVM hypervisor. On this box I have a logical 
> partition(LPAR) or guest
> (allocated with 32 cpus 90G memory) running linux-next.
>
> I started with a clean slate.
> Moved to linux-next 5.13.0-rc7-next-20210622 as base code.
> Applied patch #1 from Vincent which contains changes to dequeue_load_avg()
> Applied patch #2 from Vincent which contains changes to enqueue_load_avg()
> Applied patch #3 from Vincent which contains changes to 
> attach_entity_load_avg()
> Applied patch #4 from 
> https://lore.kernel.org/lkml/20210621174330.11258-1-vincent.guit...@linaro.org/
>
> With these changes applied I was still able to recreate the issue. I could 
> see kernel warning
> during boot.
>
> I then applied patch #5 from Odin which contains changes to 
> update_cfs_rq_load_avg()
>
> With all the 5 patches applied I was able to boot the kernel without any 
> warning messages.
> I also ran scheduler related tests from ltp (./runltp -f sched) . All tests 
> including cfs_bandwidth01
> ran successfully. No kernel warnings were observed.

ok so Odin's patch fixes the problem which highlights that we
overestimate _sum or don't sync _avg and _sum correctly

I'm going to look at this further

>
> Have also attached .config in case it is useful. config has CONFIG_HZ_100=y

Thanks, i will have a look

>
> Thanks
> -Sachin
>

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