Re: [RFC 4/8] Improve the tracking of active utilisation

From: Luca Abeni
Date: Wed Jan 27 2016 - 09:46:09 EST

Hi Peter,

On Wed, 27 Jan 2016 15:39:46 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, Jan 27, 2016 at 02:36:51PM +0100, Luca Abeni wrote:
> > Ok, so I implemented this idea, and I am currently testing it...
> > The first experiments seem to show that there are no problems, but I
> > just tried some simple workload (rt-app, or some other periodic
> > taskset scheduled by SCHED_DEADLINE). Do you have suggestions for
> > more "interesting" (and meaningful) tests/experiments?
> rt-app is the workload generator, right?
> I think the most interesting part here is the switched_from path, so
> you'd want the workload to include a !rt task that gets PI boosted to
> deadline every so often.
> Also, does rt-app let tasks die? Or does it spawn N tasks and lets
> them run jobs until the end? I think you want to put some effort in
> task_dead_dl() as well.
> After that, just make sure rt-app generates a _lot_ of tasks such that
> the migration thing gets used.

Thanks; I'll check with Juri how to do all of this with rt-app (or how
to modify rt-app to stress these functionalities).