Name: Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"
Start: 2022-02-03T14:00:00+02:00
End: 2022-02-03T15:00:00+02:00

Calendar

February 3, 2022

Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines"

11:00 am – 12:00 pm
February 3, 2022

Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"

2:00 pm – 3:00 pm
February 3, 2022

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News
- Journée au vert POLARIS 2022/05/23
- DATAMOVE/POLARIS picnic 2021/06/22
- DATAMOVE/POLARIS BBQ 2019 2019/06/14
- POLARIS Bootcamp (May 2019) 2019/05/24
- slides of Andras Gyorgy 2016/01/15
Next seminars
- 2:00 pm – 3:00 pm, April 30, 2024 – Seminar Rémi Castera

Events in February–March 2022

M	T	W	T	F	S	S
31	February 1	2	3 Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines" 11:00 am – 12:00 pm February 3, 2022 Read more Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing" 2:00 pm – 3:00 pm February 3, 2022 Read more	4	5	6
7	8	9	10 Polaris-tt: Henry-Joseph Audéoud: "NBFS: Fast Thin Clients over Slow Networks" 11:00 am – 12:00 pm February 10, 2022 Read more Polaris-Datamove seminar Panayotis Mertikopoulos: "An ill-fated attempt to summarize some recent and not-so-recent results on learning in games" 2:00 pm – 3:00 pm February 10, 2022 Title: An ill-fated attempt to summarize some recent and not-so-recent results on learning in games Abstract: see title :p Read more	11	12	13
14	15	16	17	18	19	20
21	22	23	24	25	26	27
28	March 1	2	3 Polaris-tt: Chen Yan: restless bandits and LP-relaxations 11:00 am – 12:00 pm March 3, 2022 Read more	4	5	6
7	8	9	10 Polaris-tt: Kimang Khun: computing index policies for restless bandits 11:00 am – 12:00 pm March 10, 2022 Read more	11	12	13
14	15	16	17 Polaris-tt: Till Kletti (Introducing the expohedron for fair and useful rankings) 11:00 am – 12:00 pm March 17, 2022 Based on https://dl.acm.org/doi/10.1145/3488560.3498490 Read more Seminar Bruno Raffin (Large Scale Data Assimilation) 2:00 pm – 3:00 pm March 17, 2022 Title: Large Scale Data Assimilation Authors: Sebastian Friedemann and Bruno Raffin Abstract: How to combine data, which may be available though different sensors, with traditional numerical solvers designed to compute solutions of PDEs modeling complexe phenomenon ? Bridging both is a timely question with the multiplication of data sources (IoT). But augmenting solvers working in high dimension spaces with external data is far from trivial. Both are usually subject to uncertainties. Data Assimilation (DA) is a well known approach to address this issue. DA is actually routinely used in production for weather forecast for instance. In this talk, I will first motivate and introduce the principles of Data Assimilation, including the different families of techniques (statistical, variational) with a specific focus on statistical ones (EnKF and particle filter). From there, I will explain the worked performed with the Melissa framework to support very large scale statistical data assimilation with the EnKF method. We will dive into the details of the software infrastructure that has been designed to go to very large scale, supporting features like elasticity, fault tolerance and dynamics load balancing, and show some experimental performance results. Read more	18	19	20
21	22	23	24 Polaris-tt: Victor Boone (title to be annouced) 11:00 am – 12:00 pm March 24, 2022 Read more Polaris-datamove seminar: Georges Da Costa (Multi-objective resources optimization Performance- and Energy-aware HPC and Clouds) 2:00 pm – 3:00 pm March 24, 2022 Titre: "Multi-objective resources optimization Performance- and Energy-aware HPC and Clouds" This talk will answer to the challenge "How to efficiently manage a datacenter ?" by providing theoretical and practical tools. Datacenters are at the center of the life of an increasing part of the world population while being mostly unknown: From online services to weather forcast. Their role, while transparent, is of the utmost importance. Their electricity consumption is then a key challenge, and will be even more in a near future. Managing efficiently leads to optimization of quality of service, but also to improving energy efficiency. This talk will show the required tools: The tools linked to measures and monitoring, from a technical point of view, but also by the definition of metrics. Then, it will explore methods to model such problems, along with direct or approximated resolution techniques. The next step will show several heuristics to quickly reach approximated solutions. Several types of validations, from experimental to improved simulated ones will serve as support for this talk. Read more	25	26	27
28	29	30	31 Seminar Bertrand Simon (An Exact Algorithm for the Linear Tape Scheduling Problem) 2:00 pm – 3:00 pm March 31, 2022 Title: An Exact Algorithm for the Linear Tape Scheduling Problem Abstract: Magnetic tapes are often considered as an outdated storage technology, yet they are still used to store huge amounts of data. Their main interests are a large capacity and a low price per gigabyte, which come at the cost of a much larger file access time than on disks. With tapes, finding the right ordering of multiple file accesses is thus key to performance. Moving the reading head back and forth along a kilometer long tape has a non-negligible cost and unnecessary movements thus have to be avoided. However, the optimization of tape request ordering has then rarely been studied in the scheduling literature, much less than I/O scheduling on disks. For instance, minimizing the average service time for several read requests on a linear tape remains an open question. Therefore, in this paper, we aim at improving the quality of service experienced by users of tape storage systems, and not only the peak performance of such systems. To this end, we propose a reasonable polynomial-time exact algorithm while this problem and simpler variants have been conjectured NP-hard. We also refine the proposed model by considering U-turn penalty costs accounting for inherent mechanical accelerations. Then, we propose a low-cost variant of our optimal algorithm by restricting the solution space, yet still yielding an accurate suboptimal solution. Finally, we compare our algorithms to existing solutions from the literature on logs of the mass storage management system of a major datacenter. This allows us to assess the quality of previous solutions and the improvement achieved by our low-cost algorithm. Aiming for reproducibility, we make available the complete implementation of the algorithms used in our evaluation, alongside the dataset of tape requests that is, to the best of our knowledge, the first of its kind to be publicly released. ( https://arxiv.org/abs/2112.09384 ) Read more	April 1	2	3

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Calendar

February 3, 2022

Category: Seminars Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines"

Category: Seminars Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"

News

Next seminars

Events

Events in February–March 2022

February

Category: Seminars Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines"

Category: Seminars Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"

Category: Seminars Polaris-tt: Henry-Joseph Audéoud: "NBFS: Fast Thin Clients over Slow Networks"

Category: Seminars Polaris-Datamove seminar Panayotis Mertikopoulos: "An ill-fated attempt to summarize some recent and not-so-recent results on learning in games"

March

Category: Seminars Polaris-tt: Chen Yan: restless bandits and LP-relaxations

Category: Seminars Polaris-tt: Kimang Khun: computing index policies for restless bandits

Category: Seminars Polaris-tt: Till Kletti (Introducing the expohedron for fair and useful rankings)

Category: Seminars Seminar Bruno Raffin (Large Scale Data Assimilation)

Category: Seminars Polaris-tt: Victor Boone (title to be annouced)

Category: Seminars Polaris-datamove seminar: Georges Da Costa (Multi-objective resources optimization Performance- and Energy-aware HPC and Clouds)

Category: Seminars Seminar Bertrand Simon (An Exact Algorithm for the Linear Tape Scheduling Problem)

April

Meta

Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines"

Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"

Polaris-tt: Louis-Sebastien Rebuffi "Optimal Speed Profile of a DVFS Processor under Soft Deadlines"

Seminar Arnaud Legrand: "Fairness in ”Network” Resource Sharing"

Polaris-tt: Henry-Joseph Audéoud: "NBFS: Fast Thin Clients over Slow Networks"

Polaris-Datamove seminar Panayotis Mertikopoulos: "An ill-fated attempt to summarize some recent and not-so-recent results on learning in games"

Polaris-tt: Chen Yan: restless bandits and LP-relaxations

Polaris-tt: Kimang Khun: computing index policies for restless bandits

Polaris-tt: Till Kletti (Introducing the expohedron for fair and useful rankings)

Seminar Bruno Raffin (Large Scale Data Assimilation)

Polaris-tt: Victor Boone (title to be annouced)

Polaris-datamove seminar: Georges Da Costa (Multi-objective resources optimization Performance- and Energy-aware HPC and Clouds)

Seminar Bertrand Simon (An Exact Algorithm for the Linear Tape Scheduling Problem)