Re: [PATCH 2/2] sched/fair: Always propagate runnable_load_avg

From: Tejun Heo
Date: Tue Apr 25 2017 - 17:08:24 EST


On Tue, Apr 25, 2017 at 11:49:41AM -0700, Tejun Heo wrote:
> > I have run a quick test with your patches and schbench on my platform.
> > I haven't been able to reproduce your regression but my platform is
> > quite different from yours (only 8 cores without SMT)
> > But most importantly, the parent cfs_rq->runnable_load_avg never
> > reaches 0 (or almost 0) when it is idle. Instead, it still has a
> > runnable_load_avg (this is not due to rounding computation) whereas
> > runnable_load_avg should be 0
>
> Heh, let me try that out. Probably a silly mistake somewhere.

This is from the follow-up patch. I was confused. Because we don't
propagate decays, we still should decay the runnable_load_avg;
otherwise, we end up accumulating errors in the counter. I'll drop
the last patch.

Thanks.

--
tejun