Re: [6tsch] On the fly scheduling
Guillaume Gaillard <guillaume.gaillard.maze@gmail.com> Fri, 04 October 2013 14:57 UTC
Return-Path: <guillaume.gaillard.maze@gmail.com>
X-Original-To: 6tsch@ietfa.amsl.com
Delivered-To: 6tsch@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 9D5A921F9E51 for <6tsch@ietfa.amsl.com>; Fri, 4 Oct 2013 07:57:51 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, HTML_MESSAGE=0.001, NO_RELAYS=-0.001]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AH6s6qRdWugC for <6tsch@ietfa.amsl.com>; Fri, 4 Oct 2013 07:57:20 -0700 (PDT)
Received: from mail-we0-x22a.google.com (mail-we0-x22a.google.com [IPv6:2a00:1450:400c:c03::22a]) by ietfa.amsl.com (Postfix) with ESMTP id 22EA721F9CA6 for <6tsch@ietf.org>; Fri, 4 Oct 2013 07:54:41 -0700 (PDT)
Received: by mail-we0-f170.google.com with SMTP id u57so3228737wes.15 for <6tsch@ietf.org>; Fri, 04 Oct 2013 07:54:41 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=Dep9M2eYCRTa3O8Eu+fvxDaCeawxuJOlw/k+7TWRAYg=; b=M3q1ngqNEj7c6Z7NpwnLmEhWH68U/+Yy6OHsqQYPgMQsXC9R0TOCIqCl78+T2eU8Wy G/ivMJzY/z0G1fNBDbk9eJX2Dw68x41h07MbpSwCqjNA465lyGWSPrdDaSAotgvI+uiv 9msEOOxNdwSx/m3885FZ0m2OGHECg0yAHyt9EaVaz2lP+9fc56Y6efpIjEMyAgeBnwDC /fv9ZqnHyY/3pzDf28xgRAOSuIVfSrkfg5cRVyCVFkWML7bLztM/1KzCpQYqrufMgo90 QbsE8jNNX1I2+C/IrWrtvXDAiht6WKeeSeeNYc+c3j1HI/wPTDH95b5HHD68wq5igJCd jtVg==
MIME-Version: 1.0
X-Received: by 10.194.71.72 with SMTP id s8mr2121980wju.52.1380898481170; Fri, 04 Oct 2013 07:54:41 -0700 (PDT)
Received: by 10.217.10.199 with HTTP; Fri, 4 Oct 2013 07:54:41 -0700 (PDT)
In-Reply-To: <CAAzoce6UxUX74h5xM2Bd+jC_WKT3OOyGEvGW1Q=TLWaLdkTriw@mail.gmail.com>
References: <CAH7SZV86jyR6d3LbOqqFswzUN3brPdNni3GFuD-yeDYPYktNZQ@mail.gmail.com> <CALEMV4atkUjm0yRG1oOo=ayNL2jjd1ygSc_v68JuUeCpoH4+EA@mail.gmail.com> <E045AECD98228444A58C61C200AE1BD8414CEBBD@xmb-rcd-x01.cisco.com> <F085911F642A6847987ADA23E611780D1859FA68@hoshi.uni.lux> <CADJ9OA_itqDTLObLX-bByT1cQ8s=CXvdiNkvmsSUsk-z+7CnUA@mail.gmail.com> <CAAzoce7AYoek5uL93t3bbfXnkPVwQeik4_gnytkyp6TD8YpqAw@mail.gmail.com> <CADJ9OA9kbCQeY6VtoZtSVMw-XC_Kw5b=u+8mc-R0eocR-ij-nQ@mail.gmail.com> <F085911F642A6847987ADA23E611780D185A39B6@hoshi.uni.lux> <E045AECD98228444A58C61C200AE1BD8414D2118@xmb-rcd-x01.cisco.com> <CAAzoce6UxUX74h5xM2Bd+jC_WKT3OOyGEvGW1Q=TLWaLdkTriw@mail.gmail.com>
Date: Fri, 04 Oct 2013 16:54:41 +0200
Message-ID: <CAMHDfJ7hg58RzFy64+j5V_2tm+_OtPaOhwftgAcdb9A8Z=9ACA@mail.gmail.com>
From: Guillaume Gaillard <guillaume.gaillard.maze@gmail.com>
To: Qin Wang <qinwang@berkeley.edu>
Content-Type: multipart/alternative; boundary="047d7bd91a0470f08d04e7eb7b46"
Cc: 6TSCH <6tsch@ietf.org>
Subject: Re: [6tsch] On the fly scheduling
X-BeenThere: 6tsch@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: "Discuss link layer model for Deterministic IPv6 over the TSCH mode of IEEE 802.15.4e, and impacts on RPL and 6LoWPAN such as resource allocation" <6tsch.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/6tsch>, <mailto:6tsch-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/6tsch>
List-Post: <mailto:6tsch@ietf.org>
List-Help: <mailto:6tsch-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/6tsch>, <mailto:6tsch-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 04 Oct 2013 14:57:52 -0000
Hi Qin and all, I agree with your separation into two tools (pre-allocation vs post-allocation). When one wants to meet a new QoS requirement, it is possible: - (1) to over-provision cells in the schedule in order to be "sure" to meet the requirement (pre-allocation); - (2) to adapt the cell allocation to the variations of the network parameters (post-allocation); - (3) to do both things. When solution (2) is adopted, one should tolerate a time of degraded QoS, before the requirement is restored. I agree on your list of mechanisms a solution requires. Is the algorithm (4) (matching number of cell with QoS requirements) implementation-specific ? Regards, Guillaume Gaillard Orange Labs Meylan/CITI INRIA-INSA Lyon PhD student "SLA pour Réseaux de Capteurs Multi-Services" Advisors D. Barthel, F. Valois, F. Theoleyre 2013/10/4 Qin Wang <qinwang@berkeley.edu> > Hi Pascal and all, > > It is a interesting approach. I would like to put different approaches > above together. > > Objective: meet some QoS requirement. > Tool 1: pre-allocation, like what Pascal suggested, assign number of cells > to a bundle, and on/off them on demand. > Tool 2: post-allocation, like discussed in other emails in this thread, > adjust the number of cells in a bundle according to statistics information. > > In reality, I think a mote may use the combination of tool 1 and tool 2, > e.g. at the beginning, mote allocates some cells for a bundle, and use them > in the mode of on/off on demand; when statistics information show 2 more > cells needed, then mote is triggered to allocates 3 more cells for the > bundle, and then also use them in the mode of on/off on demand. > > If it is the case, a solution should include the the following parts: > (1) mechanism to create/delete softcells > (2) mechanism to provide statistics information > (3) mechanism to on/off cell on demand > (4) algorithm to determine how many cells needed for a QoS requirement > like (dataflow/burst-feature, delay-tolerance, {statistics info}, ...) > > What do you think? > > Qin > > > > > On Fri, Oct 4, 2013 at 5:30 PM, Pascal Thubert (pthubert) < > pthubert@cisco.com> wrote: > >> Dear all:**** >> >> ** ** >> >> Statistics and hysteresis can be costly in terms of memory and CPU, may >> not be the best strategy to address bursts of traffic in a stochastic IP >> network, and the strategy to derive the allocation from the past >> observation may be hard to determine in a particular case and even harder >> to generalize.**** >> >> ** ** >> >> The needs of bandwidth may be very dynamic for instance in the case of >> alarms/alerts, or in the case of a brutal variation of monitored data. >> Changes in the network topology impacting the rank of a node within the DAG >> may also impact brutally its needs of bandwidth. So we cannot only rely on >> past observations and but also need to maintain some capabilities that rely >> on current needs that operate efficiently in terms of control and yet very >> dynamically to accept both brutal bursts of traffic and longer term >> variations.**** >> >> ** ** >> >> Considering that we have ample room in a SlotFrame, a simple strategy, >> derived from traditional memory management, could be to augment the number >> of cells in a bundle each time it is saturated. As an image, GNU’s obstack >> seem to grow linearly one chunk at a time, but I know of chunk >> implementations that double the size of a dynamic chunk each time it is >> saturated and a geometrical growth may a better approach for us. **** >> >> ** ** >> >> In a bundle, a portion of the cells is always on. The rest can stay idle >> (no wake to send or listen) unless a previous cell indicates that there is >> more to come. If we agree on a strategy like this then we can start working >> out the details, in particular how handle lazy release or one-shot >> override, how we observe unallocated slots to make them candidate for >> allocation, etc...**** >> >> ** ** >> >> As you see, even implementing such a simple strategy can already be quite >> some work in a constrained device. **** >> >> ** ** >> >> Cheers,**** >> >> ** ** >> >> Pascal**** >> >> ** ** >> >> *From:* 6tsch-bounces@ietf.org [mailto:6tsch-bounces@ietf.org] *On >> Behalf Of *Maria Rita PALATTELLA >> *Sent:* vendredi 4 octobre 2013 09:19 >> *To:* Thomas Watteyne; 6TSCH >> >> *Subject:* Re: [6tsch] On the fly scheduling**** >> >> ** ** >> >> +1 for me too.**** >> >> ** ** >> >> For sure, according to the specific requirements of the applications, >> different algorithms may be used for building the schedule. But the >> functionalities offers by 6top (i.e., collect statist. Info, send commands >> for scheduling cells) will be still the same (no matter which algorithm is >> used). **** >> >> ** ** >> >> The statistics needed could change because different algorithms may use >> different input as parameters. So, we will have to include a set of >> statistic information, or anyway, make sure it is possible to extend them. >> **** >> >> ** ** >> >> Maria Rita**** >> >> ** ** >> >> ** ** >> >> ** ** >> >> *From:* 6tsch-bounces@ietf.org [mailto:6tsch-bounces@ietf.org<6tsch-bounces@ietf.org>] >> *On Behalf Of *Thomas Watteyne >> *Sent:* Thursday, October 03, 2013 10:11 PM >> *To:* 6TSCH >> *Subject:* Re: [6tsch] On the fly scheduling**** >> >> ** ** >> >> That would indeed be clean.**** >> >> ** ** >> >> On Thu, Oct 3, 2013 at 12:33 PM, Qin Wang <qinwang@berkeley.edu> wrote:** >> ** >> >> Hi all,**** >> >> ** ** >> >> +1 for the proposal. **** >> >> ** ** >> >> Regarding to how to approach, I agree with Thomas. There is an entity >> running on top of 6top, which reads queue information and other statistics >> information from 6top, sends instruction like create/delete softcells to >> 6top. I think we can use the design methodology of Objective Function in >> RPL, i.e. define the statistics information and the interface to/from 6top, >> and leave the specific algorithm open.**** >> >> ** ** >> >> What do you think?**** >> >> ** ** >> >> Qin **** >> >> ** ** >> >> ** ** >> >> ** ** >> >> On Fri, Oct 4, 2013 at 12:45 AM, Thomas Watteyne < >> watteyne@eecs.berkeley.edu> wrote:**** >> >> +1 for the proposal.**** >> >> ** ** >> >> I believe it could be a very simple and powerful approach. Diego, would >> you agree that this can be considered a distributed mechanism sitting on >> top of 6top?**** >> >> ** ** >> >> That is, 6top provides:**** >> >> - commands to modify the number of soft cells in a bundle**** >> - commands to retrieve usage statistics of the cells/bundles**** >> >> The way I see it, your proposal consists of an algorithm which feeds >> from the usage statistics and triggers changes in the number of soft cells >> in a bundle. Correct?**** >> >> ** ** >> >> The questions to answer for now is whether 6top provides the right >> statistics.**** >> >> ** ** >> >> Maria Rita, one big difference with TASA is that OTF scheduling is >> distributed.**** >> >> ** ** >> >> Thomas**** >> >> ** ** >> >> On Thu, Oct 3, 2013 at 9:11 AM, Maria Rita PALATTELLA < >> maria-rita.palattella@uni.lu> wrote:**** >> >> Diego,( all) >> >> what you are suggesting (i.e., reserve cells based on queue size, delay) >> is actually the main idea behind TASA (Traffic Aware Scheduling Algorithm). >> >> TASA builds the schedule based on the local (number of pkt generated by >> the node) and global queue level ( i.e., local + pkt to be forwarded, >> generated by children). It gives priority to nodes with longer queues and >> it aims to reduce the latency for delivering the pkt. At the same time >> while building the schedule it minimizes the number of scheduled cells in >> order to reduce the network duty cycle. >> TASA is centralized and thus it assumes that the PCE has all the info >> needed for setting up the schedule. in other words, it knows the traffic >> generated by each nodes, and the paths followed by each pkt. >> With a "on the fly solution", we will not need to know all this info a >> priori. but we will use 6top monitoring functions and the control flows >> message for scheduling the cells. >> >> Btw, I agree with all the points raised up by Xavi. We will have to >> address his questions. >> >> And I support Pascal's suggestions about how to deal with bundle. >> >> Maria Rita**** >> ------------------------------ >> >> *From:* 6tsch-bounces@ietf.org [6tsch-bounces@ietf.org] on behalf of >> Pascal Thubert (pthubert) [pthubert@cisco.com] >> *Sent:* Thursday, October 03, 2013 4:09 PM >> *To:* xvilajosana@eecs.berkeley.edu; Prof. Diego Dujovne**** >> >> >> *Cc:* 6TSCH >> *Subject:* Re: [6tsch] On the fly scheduling**** >> >> ** ** >> >> +1 too.**** >> >> **** >> >> I think that the queue size matters at enqueue but the latency is really >> what we care for at dequeue, that is how long did this device keep this >> message in queue (even if we are far from **** >> >> buffer bloat conditions in such a device). If one of the 2 conditions >> (size at enqueue, latency at dequeue) is reached then the bundle should be >> increased. **** >> >> **** >> >> I agree with Xavi that we want to avoid changing the bundle size all the >> time. We discussed that with Qin and others earlier on the ML. One way of >> increasing the bundle dynamically at a very low cost (not even a >> hysteresis) is to have it large amount of cells from the start but used >> like 10% by default (xmit/listen happens only once in 10 time slots). A bit >> in the frame indicates whether the next (normally unused) slot will indeed >> be used. The bit can be present in the data and acked in the ack. This can >> also implicitly be triggered for retries.**** >> >> **** >> >> Please keep us tuned!**** >> >> **** >> >> Cheers,**** >> >> **** >> >> PS Note that Cisco has IPR on chaining time slots and flagging whether >> the next is used or not. We already declared our IPR against the >> architecture draft and provided terms.**** >> >> **** >> >> Pascal**** >> >> **** >> >> *From:* 6tsch-bounces@ietf.org [mailto:6tsch-bounces@ietf.org] *On >> Behalf Of *Xavier Vilajosana Guillen >> *Sent:* jeudi 3 octobre 2013 15:46 >> *To:* Prof. Diego Dujovne >> *Cc:* 6TSCH >> *Subject:* Re: [6tsch] On the fly scheduling**** >> >> **** >> >> Diego, >> >> +1**** >> >> it seems to a me a very interesting idea to explore. Maybe we can start >> putting some rules of this mechanism on the table and prepare a simulation. >> I am completely in with that idea.**** >> >> Some questions arise:**** >> >> 1-how fast do you react to changes on the queue size to avoid hysteresis >> -- i.e how do you maintain certain stability in the schedule (so you don't >> start installing and removing links very often)**** >> >> 2-how you map queue size (only one or if more than one queue) to actual >> link requirements**** >> >> 3-how you recover from link collisions in case of multiple nodes schedule >> the same cells.**** >> >> 4-how to decide to who (what neighbor) install more links according to >> queue size?**** >> >> **** >> >> cheers! >> Xavi**** >> >> **** >> >> **** >> >> On Thu, Oct 3, 2013 at 3:23 AM, Prof. Diego Dujovne < >> diego.dujovne@mail.udp.cl> wrote:**** >> >> Dear all, >> I've been looking into the idea of "on the fly scheduling", >> presented on the Sept 27th webex call as "on-the-fly decentralized >> reservation". >> The basic mechanism would be based on analysing the queue size >> on a node and dynamically adapt the number of reserved >> cells to satisfy queue size, delay and/or power >> consumption thresholds. >> This mechanism would work inside 6top, between pairs of nodes. >> As a first approach, it would be based on the minimal draft. >> What do you think on this starting point? >> I (gladly) receive comments to add or modify this proposal. >> >> Diego >> >> >> >> >> -- >> DIEGO DUJOVNE >> Académico Escuela de Ingeniería en Informática y Telecomunicaciones >> Facultad de Ingeniería UDP >> www.ingenieria.udp.cl >> (56 2) 676 8125 >> _______________________________________________ >> 6tsch mailing list >> 6tsch@ietf.org >> https://www.ietf.org/mailman/listinfo/6tsch**** >> >> **** >> >> >> _______________________________________________ >> 6tsch mailing list >> 6tsch@ietf.org >> https://www.ietf.org/mailman/listinfo/6tsch**** >> >> ** ** >> >> >> _______________________________________________ >> 6tsch mailing list >> 6tsch@ietf.org >> https://www.ietf.org/mailman/listinfo/6tsch**** >> >> ** ** >> >> ** ** >> >> _______________________________________________ >> 6tsch mailing list >> 6tsch@ietf.org >> https://www.ietf.org/mailman/listinfo/6tsch >> >> > > _______________________________________________ > 6tsch mailing list > 6tsch@ietf.org > https://www.ietf.org/mailman/listinfo/6tsch > >
- [6tsch] On the fly scheduling Prof. Diego Dujovne
- Re: [6tsch] On the fly scheduling Xavier Vilajosana Guillen
- Re: [6tsch] On the fly scheduling Pascal Thubert (pthubert)
- Re: [6tsch] On the fly scheduling Maria Rita PALATTELLA
- Re: [6tsch] On the fly scheduling Thomas Watteyne
- Re: [6tsch] On the fly scheduling Maria Rita PALATTELLA
- Re: [6tsch] On the fly scheduling Qin Wang
- Re: [6tsch] On the fly scheduling Thomas Watteyne
- Re: [6tsch] On the fly scheduling Maria Rita PALATTELLA
- Re: [6tsch] On the fly scheduling Pascal Thubert (pthubert)
- Re: [6tsch] On the fly scheduling Qin Wang
- Re: [6tsch] On the fly scheduling Kris Pister
- Re: [6tsch] On the fly scheduling Guillaume Gaillard
- Re: [6tsch] On the fly scheduling Qin Wang
- Re: [6tsch] On the fly scheduling Guillaume Gaillard