Re: weird loadavg on idle machine post 5.7

[Dave Jones]

On Fri, Jul 03, 2020 at 12:40:33PM +0200, Peter Zijlstra wrote:
 
 > So ARM/Power/etc.. can speculate the load such that the
 > task_contributes_to_load() value is from before ->on_rq.
 > 
 > The compiler might similar re-order things -- although I've not found it
 > doing so with the few builds I looked at.
 > 
 > So I think at the very least we should do something like this. But i've
 > no idea how to reproduce this problem.
 > 
 > Mel's patch placed it too far down, as the WF_ON_CPU path also relies on
 > this, and by not resetting p->sched_contributes_to_load it would skew
 > accounting even worse.

looked promising the first few hours, but as soon as it hit four hours
of uptime, loadavg spiked and is now pinned to at least 1.00

	Dave