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From: Luca Abeni <luca.abeni@unitn.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Raistlin <raistlin@linux.it>, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	Chris Friesen <cfriesen@nortel.com>,
	oleg@redhat.com, Frederic Weisbecker <fweisbec@gmail.com>,
	Darren Hart <darren@dvhart.com>,
	Johan Eker <johan.eker@ericsson.com>,
	"p.faure" <p.faure@akatech.ch>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Claudio Scordino <claudio@evidence.eu.com>,
	michael trimarchi <trimarchi@retis.sssup.it>,
	Fabio Checconi <fabio@gandalf.sssup.it>,
	Tommaso Cucinotta <cucinotta@sssup.it>,
	Juri Lelli <juri.lelli@gmail.com>,
	Nicola Manica <nicola.manica@disi.unitn.it>,
	Dhaval Giani <dhaval@retis.sssup.it>,
	Harald Gustafsson <hgu1972@gmail.com>,
	paulmck <paulmck@linux.vnet.ibm.com>
Subject: Re: [RFC][PATCH 18/22] sched: add reclaiming logic to -deadline tasks
Date: Fri, 12 Nov 2010 18:41:57 +0100	[thread overview]
Message-ID: <4CDD7C65.9090400@unitn.it> (raw)
In-Reply-To: <1289577841.2084.302.camel@laptop>

On 12/11/10 17:04, Peter Zijlstra wrote:
> On Fri, 2010-11-12 at 16:36 +0100, Raistlin wrote:
>> But at this point I can't avoid asking. That model aims at _pure_
>> hard real-time scheduling *without* resource reservation capabilities,
>> provided it deals with temporal overruns by means of a probabilistic
>> analysis, right?
>
>> From what I understood from it, its a soft real-time scheduling
> algorithm with resource reservation. It explicitly allows for deadline
> misses, but requires the tardiness of those misses to be bounded, ie.
> the UNC soft real-time definition.
>
> The problem the stochastic execution time model tries to address is the
> WCET computation mess, WCET computation is hard and often overly
> pessimistic, resulting in under-utilized systems.
[...]
BTW, sorry for the shameless plug, but even with the current 
SCHED_DEADLINE you are not forced to dimension the runtime using the 
WCET. You can use some stochastic analysis, providing probabilistic 
deadline guarantees. See (for example) "QoS Guarantee Using 
Probabilistic Deadlines"
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.22.7683&rep=rep1&type=pdf
and "Stochastic analysis of a reservation based system"
http://www.computer.org/portal/web/csdl/doi?doc=doi/10.1109/IPDPS.2001.925049
(sorry, this is not easy to download... But I can provide a copy if you 
are interested).


			Luca

  reply	other threads:[~2010-11-12 17:45 UTC|newest]

Thread overview: 135+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-29  6:18 [RFC][PATCH 00/22] sched: SCHED_DEADLINE v3 Raistlin
2010-10-29  6:25 ` [RFC][PATCH 01/22] sched: add sched_class->task_dead Raistlin
2010-10-29  6:27 ` [RFC][PATCH 02/22] sched: add extended scheduling interface Raistlin
2010-11-10 16:00   ` Dhaval Giani
2010-11-10 16:12     ` Dhaval Giani
2010-11-10 22:45       ` Raistlin
2010-11-10 16:17     ` Claudio Scordino
2010-11-10 17:28   ` Peter Zijlstra
2010-11-10 19:26     ` Peter Zijlstra
2010-11-10 23:33       ` Tommaso Cucinotta
2010-11-11 12:19         ` Peter Zijlstra
2010-11-10 22:17     ` Raistlin
2010-11-10 22:57       ` Tommaso Cucinotta
2010-11-11 13:32       ` Peter Zijlstra
2010-11-11 13:54         ` Raistlin
2010-11-11 14:08           ` Peter Zijlstra
2010-11-11 17:27             ` Raistlin
2010-11-11 14:05         ` Dhaval Giani
2010-11-10 22:24     ` Raistlin
2010-11-10 18:50   ` Peter Zijlstra
2010-11-10 22:05     ` Raistlin
2010-11-12 16:38   ` Steven Rostedt
2010-11-12 16:43     ` Peter Zijlstra
2010-11-12 16:52       ` Steven Rostedt
2010-11-12 19:19         ` Raistlin
2010-11-12 19:23           ` Steven Rostedt
2010-11-12 17:42     ` Tommaso Cucinotta
2010-11-12 19:21       ` Steven Rostedt
2010-11-12 19:24     ` Raistlin
2010-10-29  6:28 ` [RFC][PATCH 03/22] sched: SCHED_DEADLINE data structures Raistlin
2010-11-10 18:59   ` Peter Zijlstra
2010-11-10 22:06     ` Raistlin
2010-11-10 19:10   ` Peter Zijlstra
2010-11-12 17:11     ` Steven Rostedt
2010-10-29  6:29 ` [RFC][PATCH 04/22] sched: SCHED_DEADLINE SMP-related " Raistlin
2010-11-10 19:17   ` Peter Zijlstra
2010-10-29  6:30 ` [RFC][PATCH 05/22] sched: SCHED_DEADLINE policy implementation Raistlin
2010-11-10 19:21   ` Peter Zijlstra
2010-11-10 19:43   ` Peter Zijlstra
2010-11-11  1:02     ` Raistlin
2010-11-10 19:45   ` Peter Zijlstra
2010-11-10 22:26     ` Raistlin
2010-11-10 20:21   ` Peter Zijlstra
2010-11-11  1:18     ` Raistlin
2010-11-11 13:13       ` Peter Zijlstra
2010-11-11 14:13   ` Peter Zijlstra
2010-11-11 14:28     ` Raistlin
2010-11-11 14:17   ` Peter Zijlstra
2010-11-11 18:33     ` Raistlin
2010-11-11 14:25   ` Peter Zijlstra
2010-11-11 14:33     ` Raistlin
2010-11-14  8:54   ` Raistlin
2010-11-23 14:24     ` Peter Zijlstra
2010-10-29  6:31 ` [RFC][PATCH 06/22] sched: SCHED_DEADLINE handles spacial kthreads Raistlin
2010-11-11 14:31   ` Peter Zijlstra
2010-11-11 14:50     ` Dario Faggioli
2010-11-11 14:34   ` Peter Zijlstra
2010-11-11 15:27     ` Oleg Nesterov
2010-11-11 15:43       ` Peter Zijlstra
2010-11-11 16:32         ` Oleg Nesterov
2010-11-13 18:35           ` Peter Zijlstra
2010-11-13 19:58             ` Oleg Nesterov
2010-11-13 20:31               ` Peter Zijlstra
2010-11-13 20:51                 ` Peter Zijlstra
2010-11-13 23:31                   ` Peter Zijlstra
2010-11-15 20:06                     ` [PATCH] sched: Simplify cpu-hot-unplug task migration Peter Zijlstra
2010-11-17 19:27                       ` Oleg Nesterov
2010-11-17 19:42                         ` Peter Zijlstra
2010-11-18 14:05                           ` Oleg Nesterov
2010-11-18 14:24                             ` Peter Zijlstra
2010-11-18 15:32                               ` Oleg Nesterov
2010-11-18 14:09                       ` [tip:sched/core] " tip-bot for Peter Zijlstra
2010-11-11 14:46   ` [RFC][PATCH 06/22] sched: SCHED_DEADLINE handles spacial kthreads Peter Zijlstra
2010-10-29  6:32 ` [RFC][PATCH 07/22] sched: SCHED_DEADLINE push and pull logic Raistlin
2010-11-12 16:17   ` Peter Zijlstra
2010-11-12 21:11     ` Raistlin
2010-11-14  9:14     ` Raistlin
2010-11-23 14:27       ` Peter Zijlstra
2010-10-29  6:33 ` [RFC][PATCH 08/22] sched: SCHED_DEADLINE avg_update accounting Raistlin
2010-11-11 19:16   ` Peter Zijlstra
2010-10-29  6:34 ` [RFC][PATCH 09/22] sched: add period support for -deadline tasks Raistlin
2010-11-11 19:17   ` Peter Zijlstra
2010-11-11 19:31     ` Raistlin
2010-11-11 19:43       ` Peter Zijlstra
2010-11-11 23:33         ` Tommaso Cucinotta
2010-11-12 13:33         ` Raistlin
2010-11-12 13:45           ` Peter Zijlstra
2010-11-12 13:46       ` Luca Abeni
2010-11-12 14:01         ` Raistlin
2010-10-29  6:35 ` [RFC][PATCH 10/22] sched: add a syscall to wait for the next instance Raistlin
2010-11-11 19:21   ` Peter Zijlstra
2010-11-11 19:33     ` Raistlin
2010-10-29  6:35 ` [RFC][PATCH 11/22] sched: add schedstats for -deadline tasks Raistlin
2010-10-29  6:36 ` [RFC][PATCH 12/22] sched: add runtime reporting " Raistlin
2010-11-11 19:37   ` Peter Zijlstra
2010-11-12 16:15     ` Raistlin
2010-11-12 16:27       ` Peter Zijlstra
2010-11-12 21:12         ` Raistlin
2010-10-29  6:37 ` [RFC][PATCH 13/22] sched: add resource limits " Raistlin
2010-11-11 19:57   ` Peter Zijlstra
2010-11-12 21:30     ` Raistlin
2010-11-12 23:32       ` Peter Zijlstra
2010-10-29  6:38 ` [RFC][PATCH 14/22] sched: add latency tracing " Raistlin
2010-10-29  6:38 ` [RFC][PATCH 15/22] sched: add traceporints " Raistlin
2010-11-11 19:54   ` Peter Zijlstra
2010-11-12 16:13     ` Raistlin
2010-10-29  6:39 ` [RFC][PATCH 16/22] sched: add SMP " Raistlin
2010-10-29  6:40 ` [RFC][PATCH 17/22] sched: add signaling overrunning " Raistlin
2010-11-11 21:58   ` Peter Zijlstra
2010-11-12 15:39     ` Raistlin
2010-11-12 16:04       ` Peter Zijlstra
2010-10-29  6:42 ` [RFC][PATCH 19/22] rtmutex: turn the plist into an rb-tree Raistlin
2010-10-29  6:42 ` [RFC][PATCH 18/22] sched: add reclaiming logic to -deadline tasks Raistlin
2010-11-11 22:12   ` Peter Zijlstra
2010-11-12 15:36     ` Raistlin
2010-11-12 16:04       ` Peter Zijlstra
2010-11-12 17:41         ` Luca Abeni [this message]
2010-11-12 17:51           ` Peter Zijlstra
2010-11-12 17:54             ` Luca Abeni
2010-11-13 21:08             ` Raistlin
2010-11-12 18:07           ` Tommaso Cucinotta
2010-11-12 19:07             ` Raistlin
2010-11-13  0:43             ` Peter Zijlstra
2010-11-13  1:49               ` Tommaso Cucinotta
2010-11-12 18:56         ` Raistlin
     [not found]           ` <80992760-24F2-42AE-AF2D-15727F6A1C81@email.unc.edu>
2010-11-15 18:37             ` James H. Anderson
2010-11-15 19:23               ` Luca Abeni
2010-11-15 19:49                 ` James H. Anderson
2010-11-15 19:39               ` Luca Abeni
2010-11-15 21:34               ` Raistlin
2010-10-29  6:43 ` [RFC][PATCH 20/22] sched: drafted deadline inheritance logic Raistlin
2010-11-11 22:15   ` Peter Zijlstra
2010-11-14 12:00     ` Raistlin
2010-10-29  6:44 ` [RFC][PATCH 21/22] sched: add bandwidth management for sched_dl Raistlin
2010-10-29  6:45 ` [RFC][PATCH 22/22] sched: add sched_dl documentation Raistlin

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