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

From: luca abeni <luca.abeni@unitn.it>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Juri Lelli <juri.lelli@arm.com>
Subject: Re: [RFC 4/8] Improve the tracking of active utilisation
Date: Thu, 28 Jan 2016 14:48:32 +0100	[thread overview]
Message-ID: <20160128144832.1f95ff44@utopia> (raw)
In-Reply-To: <CAKfTPtAt0gTwk9aAZN238NT1O-zJvxVQDTh2QN_KxAnE61xMww@mail.gmail.com>

On Thu, 28 Jan 2016 14:05:44 +0100
Vincent Guittot <vincent.guittot@linaro.org> wrote:

> Hi Luca,
> 
> 
> On 27 January 2016 at 15:45, Luca Abeni <luca.abeni@unitn.it> wrote:
> 
> > Hi Peter,
> >
> > On Wed, 27 Jan 2016 15:39:46 +0100
> > Peter Zijlstra <peterz@infradead.org> 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).
> >
> 
> This version of workload generator /rt-app can do all sequences you
> want:
> https://git.linaro.org/power/rt-app.git/shortlog/refs/heads/master
Thanks Vincent; I am going to have a look at it.
Are the "lock_order" and "resources" task parameters documented or
described somewhere?


			Thanks,
				Luca

> The merge of these changes are ongoing but still not finished.
> 
> Let me know if you need help to use it and create some use cases
> 
> Regards,
> Vincent
> 
> 
> >
> >
> >                         Thanks,
> >                                 Luca
> >