Re: [PATCH 0/4 v4] sched/rt: track rt rq utilization

[Vincent Guittot]

On 14 April 2018 at 12:07, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
>
> What I don't see in this patch-set is removal of the current rt_avg
> stuff.

This RT load tracking doesn't replace current rt_avg because they are
not using same period and providing same function
current rt_avg uses sysctl_sched_time_avg to define the averaging
period and it's default period is 1 second. But PELT uses a fixed
period
current rt_avg is tracking irq accounting which this patch doesn't do.
This is probably doable but will need more complex changes

Replacing current rt_avg by this new RT utilization tracking would
require more complex changes so I didn't want to add them this 1st
step.


>
> And I didn't look closely enough; but are the root cfs and rt pelt
> windows aligned? They really should be; otherwise you can't combine them
> sanely.

No They are not aligned.
I agree that this could generate some variation on the sum. I'm going
to fix this point