Résultat de la recherche
Evaluating the Cost and Robustness of Self-organizing Distributed Hash Tables
Self-organizing construction principles are a natural fit for large-scale distributed system in unpredictable deployment environments. These principles allow a system to systematically converge to a global state by means of simple, uncoordinated actions by individual peers. Indexing services based on the distributed hash table (DHT) abstraction have been established as a solid foundation for large-scale distributed applications. For most DHTs, the creation and maintenance of the overlay structure relies on the exploration and update of an already stabilized structure. We evaluate in this paper the practical interest of self-organizing principles, and in particular gossip-based overlay construction protocols, to bootstrap and maintain various DHT implementations. Based on the seminal work on T-Chord, a self-organizing version of Chord using the T-Man overlay construction service, we contribute three additional self-organizing DHTs: T-Pastry, T-Kademlia and T-Kelips. We conduct an experimental evaluation of the cost and performance of each of these designs using a prototype implementation. Our conclusion is that, while providing equivalent performance in a stabilized system, self-organizing DHTs are able to sustain and recover from higher level of churn than their explicitly-created counterparts, and should therefore be considered as a method of choice for deploying robust indexing layers in adverse environments.
Parallélisme, Architecture et Systèmes : Panorama de la Recherche Francophone
Les huit articles proposés au lecteur reflètent la diversité et le dynamisme de la recherche en France et dans les pays voisins autour de l’architecture, du parallélisme et des systèmes. Ils couvrent des sujets aussi variés que complémentaires : l’architecture des réseaux de communication pour processeurs à grand nombre de cœurs et la simulation efficace de tels processeurs ; les mécanismes de synchronisation passant à l’échelle pour ces processeurs mais aussi pour un contexte de système réparti ; la gestion efficace de systèmes virtualisés que ce soit pour la communication entre machines virtuelles ou la gestion efficace de leur mémoire mutualisée, ou enfin la compréhension du comportement des applications afin d’évaluer l’impact des grandes échelles sur leur comportement, que ce soit dans un contexte de calcul à haute performance ou dans celui des jeux vidéos massivement multijoueurs.
Efficient and Confidentiality-Preserving Content-Based Publish/Subscribe with Prefiltering
Holons: towards a systematic approach to composing systems of systems
The world’s computing infrastructure is increasingly differ- entiating into self-contained distributed systems with vari- ous purposes and capabilities (e.g. IoT installations, clouds, VANETs, WSNs, CDNs, . . . ). Furthermore, such systems are increasingly being composed to generate systems of sys- tems that offer value-added functionality. Today, however, system of systems composition is typically ad-hoc and fragile. It requires developers to possess an intimate knowledge of system internals and low-level interactions between their components. In this paper, we outline a vision and set up a research agenda towards the generalised programmatic construction of distributed systems as compositions of other distributed systems. Our vision, in which we refer uniformly to systems and to compositions of systems as holons, employs code generation techniques and uses common abstractions, operations and mechanisms at all system levels to support uniform system of systems composition. We believe our holon approach could facilitate a step change in the convenience and correctness with which systems of systems can be built, and open unprecedented opportunities for the emergence of new and previously-unenvisaged distributed system deploy- ments, analogous perhaps to the impact the mashup culture has had on the way we now build web applications.
OpenStack-based Clouds as Holons: A Functional Perspective
The generalization of distributed systems-of-systems lead to increasing management and operation complexity. A sound approach to deal with this complexity is to leverage overlay networks and the higher level of abstraction they allow for distributed operations. In particular, the virtualization of underlying network resources allows providing a range of reusable network services and compose them with existing systems. Recently, the notion of holons as compositional systems entities was proposed as a general framework for the programming and deployment of complex systems of systems. We investigate if this abstract model can be applied to the complex process of real-time composition of OpenStack-based IaaS clouds. In this context, we also address issues related to the energy-performance tradeoff using techniques similar to those involving dynamic service consolidations. Our solution aims at simplifying the life of infrastructure and service providers, allowing them to face the dynamicity of new demands in Future Internet.
Exploiting Concurrency in Domain-Specific Data Structures: A Concurrent Order Book and Workload Generator for Online Trading
Construction universelle d’objets partagés sans connaissance des participants
Une construction universelle est un algorithme permettant à un ensemble de processus concurrents d’accéder à un objet partagé en ayant l’illusion que celui-ci est disponible localement. blue Nous présentons un algorithme permettant la mise en œuvre d’une telle construction dans un système à mémoire partagée. Notre construction est sans verrou, et contrairement aux approches proposées précédemment, ne nécessite pas que les processus accédant à l’objet partagé soient connus. De plus, elle est adaptative : en notant n le nombre total de processus dans le système et k < n le nombre de processus qui utilisent l’objet partagé, tout processus effectue Θ(k) pas de calcul en l’absence de contention.