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- PublicationMétadonnées seulementExperiences with object group systems(2000)
;Guerraoui, Rachid ;Eugster, Patrick ; ;Garbinato, BenoitMazouni, KarimThe GARF, East, and OGS systems represent the resulting efforts of a multi-year 'object group' program at the Swiss Federal Institute of Technology in Lausanne, The intent of the program was to understand the extent to which one could build flexible and performance system supports to encapsulate object plurality, That is, we experimented with various ways to build libraries and services to support object groups in a distributed setting. This paper summarizes the main steps of the efforts and draws some conclusions about the successes and failures of our approaches. Copyright (C) 2000 John Wiley & Sons, Ltd.
- PublicationMétadonnées seulementScheduling Support for Transactional Memory Contention Management(2010)
; ; ; ;Suissa, Adi ;Hendler, Danny ;Fedorova, Alexandra ;Lawall, JuliaMuller, Gilles
- PublicationMétadonnées seulementProgramming with object groups in PHOENIX(Paris: Prentice Hall, 1995)
- PublicationMétadonnées seulementDesign choices for content distribution in P2P networks(2005)
;Al Hamra, AnwarContent distribution using the P2P paradigm has become one of the most dominant services in the Internet today. Most of the research effort in this area focuses on developing new distribution architectures. However, little work has gone into identifying the principle design choices that draw the behavior of the system. In this paper, we identify these design choices and show how they influence the performance of different P2P architectures. For example, we discuss how clients should organize and cooperate in the network. We believe that our findings can serve as guidelines in the design of efficient future architectures.
- PublicationMétadonnées seulementRight Abstractions on Adequate Frameworks for Building Adaptable Distributed Applications(1997)
;Garbinato, Benoit ;Guerraoui, Rachid
- PublicationMétadonnées seulementLeveraging Transactional Memory for Energy-efficient Computing below Safe Operation Margins(2013)
;Cristal, Adrian ;Unsal, Osman ;Yalcin, Gulay ;Fetzer, Christof ;Wamhoff, Jons-Tobias ; ;
- PublicationMétadonnées seulementEvaluating CORBA portability: The case of an Object Group Service(: Ieee, 1998)
; ;Guerraoui, RachidSchiper, AndréOne of the most attractive aspects of the Common Object Request Broker Architecture (CORBA) lies in its open standard nature. Code that is based only on constructs described in the CORBA specification is portable between Object Request Brokers (ORBs), without depending on any single ORE implementation However this portability feature is not completely achieved in real-world applications. This paper discusses CORBA portability issues through our experience in implementing a CORBA Object Group Service (OGS) and porting it on different ORBs. In particular we discuss some implementation choices we made with Orbix and VisiBroker and we point the impact of these choices on the service portability and interoperability. This sheds some light on whether the current CORBA specification is mature enough to be deployed in industrial systems that have requirements regarding portability and interoperability. Ne also present how new CORBA specifications solve part of the shortcomings mentioned in this paper.
- PublicationMétadonnées seulementCADA: Collaborative Auditing for Distributed Aggregation(2012-5-8)
;Valerio, José ; ;Rajman, MartinThe aggregation of distributions, composed of the number of occurrences of each element in a set, is an operation that lies at the heart of several large-scale distributed applications. Examples include popularity tracking, recommendation systems, trust management, or popularity measurement mechanisms. These applications typically span multiple administrative domains that do not trust each other and are sensitive to biases in the distribution aggregation: the results can only be trusted if inserted values were not altered nor forged, and if nodes collecting the insertions do not arbitrarily modify the aggregation results. In order to increase the level of trust that can be granted to applications, there must be a disincentive for servers to bias the aggregation results. In this paper we present the CADA auditing mechanisms that let aggregation servers collaboratively and periodically audit one another based on probabilistic tests over server-local state. CADA differs from the existing work on accountability in that it leverages the nature of the operation being performed by the node rather than a general and application-oblivious model of the computation. The effectiveness of CADA is conveyed by an experimental evaluation that studies its ability to detect malevolent behaviors using lightweight auditing oracles.
- PublicationMétadonnées seulementEfficient search in unstructured peer-to-peer networks(2004)
;Cholvi, Vicent ;Biersack, ErnstThe huge popularity of recent peer-to-peer (P2P) file sharing systems has been mainly driven by the scalability of their architectures and the flexibility of their search facilities. Such systems are usually designed as unstructured P2P networks, because they impose few constraints on topology and data placement and support highly versatile search mechanisms. A major limitation of unstructured P2P networks lies, however, in the inefficiency of their search algorithms, which are usually based on simple flooding schemes. In this paper, we propose novel mechanisms for improving search efficiency in unstructured P2P networks. Unlike other approaches, we do not rely on specialized search algorithms; instead, the peers perform local dynamic topology adaptations, based on the query traffic patterns, in order to spontaneously create communities of peers that share similar interests. The basic premise of such semantic communities is that file requests have a high probability of being fulfilled within the community they originate from, therefore increasing the search efficiency. We propose further extensions to balance the load among the peers and reduce the query traffic. Extensive simulations under realistic operating conditions substantiate that our techniques significantly improve the search efficiency and reduce the network load. Copyright (C) 2004 AEI.
- PublicationMétadonnées seulementExploiting Concurrency in Domain-Specific Data Structures: A Concurrent Order Book and Workload Generator for Online Trading(2016-5-18)
; ; ;Concurrent programming is essential to exploit parallel processing capabilities of modern multi-core CPUs. While there exist many languages and tools to simplify the development of concurrent programs, they are not always readily applicable to domain-specific problems that rely on complex shared data structures associated with various semantics (e.g., priorities or consistency). In this paper, we explore such a domain-specific application from the financial field, where a data structure—an order book —is used to store and match orders from buyers and sellers arriving at a high rate. This application has interesting characteristics as it exhibits some clear potential for parallelism, but at the same time it is relatively complex and must meet some strict guarantees, notably w.r.t. the ordering of operations. We first present an accurate yet slightly simplified description of the order book problem and describe the challenges in paral- lelizing it. We then introduce several approaches for introducing concurrency in the shared data structure, in increasing order of sophistication starting from lock-based techniques to partially lock-free designs. We propose a comprehensive workload generator for constructing histories of orders according to realistic models from the financial domain. We finally perform an evaluation and comparison of the different concurrent designs.