From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S933372AbcA0OqG (ORCPT <rfc822;w@1wt.eu>);
	Wed, 27 Jan 2016 09:46:06 -0500
Received: from mail-wm0-f43.google.com ([74.125.82.43]:33468 "EHLO
	mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S932555AbcA0Op7 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 27 Jan 2016 09:45:59 -0500
Date: Wed, 27 Jan 2016 15:45:52 +0100
From: Luca Abeni <luca.abeni@unitn.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: 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
Message-ID: <20160127154552.7fafeba8@luca-1225C>
In-Reply-To: <20160127143946.GR6357@twins.programming.kicks-ass.net>
References: <1452785094-3086-1-git-send-email-luca.abeni@unitn.it>
	<1452785094-3086-5-git-send-email-luca.abeni@unitn.it>
	<20160114194323.GC6357@twins.programming.kicks-ass.net>
	<569E29FD.9040909@unitn.it>
	<20160119134739.GY6357@twins.programming.kicks-ass.net>
	<20160127143651.4de18ad9@luca-1225C>
	<20160127143946.GR6357@twins.programming.kicks-ass.net>
X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

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).


			Thanks,
				Luca