A Scheduler-Level Incentive Mechanism for Energy Efficiency in HPC

International audienceEnergy consumption has become one of the most important factors in High Performance Computing platforms. However, while there are various algorithmic and programming techniques to save energy, a user has currently no incentive to employ them, as they might result in worse performance. We propose to manage the energy budget of a supercomputer through EnergyFairShare (EFS), a FairShare-like scheduling algorithm. FairShare is a classic scheduling rule that prioritizes jobs belonging to users who were assigned small amount of CPU-second in the past. Similarly, EFS keeps track of users 'consumption of Watt-seconds and prioritizes those whom jobs consumed less energy. Therefore, EFS incentives users to optimize their code for energy efficiency. Having higher priority, jobs have smaller queuing times and, thus, smaller turn-around time. To validate this principle, we implemented EFS in a scheduling simulator and processed workloads from various HPC centers. The results show that, by reducing it energy consumption, auser will reduce it stretch (slowdown), compared to increasing it energy consumption. To validate the general feasibility odour approach, we also implemented EFS as an extension forSLURM, a popular HPC resource and job management system.We validated our plugin both by emulating a large scale platform, and by experiments upon a real cluster with monitored energy consumption. We observed smaller waiting times for energy efficient users

A batch scheduler with high level components

In this article we present the design choices and the evaluation of a batch scheduler for large clusters, named OAR. This batch scheduler is based upon an original design that emphasizes on low software complexity by using high level tools. The global architecture is built upon the scripting language Perl and the relational database engine Mysql. The goal of the project OAR is to prove that it is possible today to build a complex system for ressource management using such tools without sacrificing efficiency and scalability. Currently, our system offers most of the important features implemented by other batch schedulers such as priority scheduling (by queues), reservations, backfilling and some global computing support. Despite the use of high level tools, our experiments show that our system has performances close to other systems. Furthermore, OAR is currently exploited for the management of 700 nodes (a metropolitan GRID) and has shown good efficiency and robustness

Large-scale experiment for topology-aware resource management

International audienceA Resource and Job Management System (RJMS) is a crucial system software part of the HPC stack. It is responsible for efficiently delivering computing power to applications in supercomputing environments and its main intelligence relies on resource selection techniques to find the most adapted resources to schedule the users' jobs. In [8], we introduced a new topology-aware resource selection algorithm to determine the best choice among the available nodes of the platform based on their position in the network and on application behaviour (expressed as a communication matrix). We did integrate this algorithm as a plugin in Slurm and validated it with several optimization schemes by making comparisons with the default Slurm algorithm. This paper presents further experiments with regard to this selection process

Adaptive Resource and Job Management for Limited Power Consumption

International audienceThe last decades have been characterized by anever growing requirement in terms of computing and storage resources.This tendency has recently put the pressure on the abilityto efficiently manage the power required to operate the hugeamount of electrical components associated with state-of-the-arthigh performance computing systems. The power consumption ofa supercomputer needs to be adjusted based on varying powerbudget or electricity availabilities. As a consequence, Resourceand Job Management Systems have to be adequately adaptedin order to efficiently schedule jobs with optimized performancewhile limiting power usage whenever needed.We introduce in this paper a new scheduling strategy thatcan adapt the executed workload to a limited power budget. Theoriginality of this approach relies upon a combination of speedscaling and node shutdown techniques for power reductions. It isimplemented into the widely used resource and job managementsystem SLURM. Finally, it is validated through large scale emulationsusing real production workload traces of the supercomputerCurie

TANGO: Transparent heterogeneous hardware Architecture deployment for eNergy Gain in Operation

The paper is concerned with the issue of how software systems actually use Heterogeneous Parallel Architectures (HPAs), with the goal of optimizing power consumption on these resources. It argues the need for novel methods and tools to support software developers aiming to optimise power consumption resulting from designing, developing, deploying and running software on HPAs, while maintaining other quality aspects of software to adequate and agreed levels. To do so, a reference architecture to support energy efficiency at application construction, deployment, and operation is discussed, as well as its implementation and evaluation plans.Comment: Part of the Program Transformation for Programmability in Heterogeneous Architectures (PROHA) workshop, Barcelona, Spain, 12th March 2016, 7 pages, LaTeX, 3 PNG figure

Topology-Aware Job Mapping

International audienceA Resource and Job Management System (RJMS) is a crucial system software part of the HPC stack. It is responsible for eciently delivering computing power to applications in supercomputing environments. Its main intelligence relies on resource selection techniques to find the most adapted resources to schedule the users' jobs. This paper introduces a new method that takes into account the topology of the machine and the application characteristics to determine the best choice among the available nodes of the platform, based upon the network topology and taking into account the applications communication pattern. To validate our approach, we integrate this algorithm as a plugin for Slurm, a well-known and widespread RJMS. We assess our plugin with di↵erent optimization schemes by comparing with the default topology-aware Slurm algorithm, using both emulation and simulation of a large-scale platform and by carrying out experiments in a real cluster. We show that transparently taking into account a job communication pattern and the topology allows for relevant performance gains

The evolution of labour law in the new member states of the European Union : 1995-2005 - country studies on Cyprus and Malta

This Report traces the development of Labour Law and the implications for Industrial Relations, as well as social and employment policy more generally, in the two small Mediterranean countries of Cyprus and Malta during the period 1995–2005. This period was particularly important for the two countries as it coincided with their efforts for accession to the European Union (EU) and the process of harmonisation with the Acquis Communautaire. Since their independence in 1960 and 1964 respectively for Cyprus and Malta, successive Governments in each country – working with the social partners – had sought to steer a policy of social cohesion to underpin their development efforts. Whilst these strategies were successful in fostering a long period of economic growth and peaceful labour relations, a major outcome was the existence of relatively inflexible labour markets. Liberalisation and globalisation of international markets, coupled with the pressure exerted by the accession process, which required the implementation of the Acquis Communautaire necessitated a series of changes with far reaching implications in social and economic affairs. Naturally the framework of Labour Law – and labour practices thereof – came under increasing pressure to adapt and reform. The Executive Summary describes the main aims and objectives of the Report on the evolution of Labour Law in Cyprus and Malta in the period 1995-2005, and provides an outline of the component chapters. Specifically the Report is divided into three chapters. The first and second chapters consist of the individual Reports on Cyprus and Malta respectively. These constitute the main body of the Report and investigate the evolution of Labour Law in the two countries separately and the implications for Industrial Relations, employment and social policy. The third chapter provides a concluding overview of the two countries’ experiences and an evaluation of the state of implementation of the Acquis Communautaire in the fields examined.peer-reviewe

Investigating Students' Motivation and Cultural Heritage Learning in a Gamified Versus Non-gamified VR Environment

This empirical study investigated how the use of a gamified versus a non-gamified Virtual Reality (VR) learning environment impacted student motivation and learning outcomes in the context of a virtual visit at a cultural heritage site. For this purpose, we adopted an experimental research design to analyse the experience of 46 undergraduate university students; 23 of them used a gamified version of the VR learning environment, while 23 of them used the same VR environment without the gamification elements. Data were collected using pre and post learning assessments, motivation questionnaires, as well as individual semistructured interviews. The data analyses showed that students who experienced the gamified VR learning environment had greater learning gains and perceived competence, as compared to their counterparts who used the VR environment without the gamification elements. The findings of this research contribute to the principled design of VR environments to optimize students' knowledge acquisition and learning experience

A batch scheduler with high level components

International audienceIn this article we present the design choices and the evaluation of a batch scheduler for large clusters, named OAR. This batch scheduler is based upon an original design that emphasizes on low software complexity by using high level tools. The global architecture is built upon the scripting language Perl and the relational database engine Mysql. The goal of the project OAR is to prove that it is possible today to build a complex system for ressource management using such tools without sacrificing efficiency and scalability. Currently, our system offers most of the important features implemented by other batch schedulers such as priority scheduling (by queues), reservations, backfilling and some global computing support. Despite the use of high level tools, our experiments show that our system has performances close to other systems. Furthermore, OAR is currently exploited for the management of 700 nodes (a metropolitan GRID) and has shown good efficiency and robustness