TechTalks from event: IEEE IPDPS 2011

Note 1: Only plenary sessions (keynotes, panels, and best papers) are accessible without requiring log-in. For other talks, you will need to log-in using the email you registered for IPDPS 2011. Note 2: Many of the talks (those without a thumbnail next to the their description below) are yet to be uploaded. Some of them were not recorded because of technical problems. We are working with the corresponding authors to upload the self-recorded versions here. We sincerely thank all authors for their efforts in making their videos available.

SESSION 18: Distributed Systems

  • GRAL: A Grouping Algorithm to Optimize Application Placement in Wireless Embedded Systems Authors: Nikos Tziritas (University of Thessaly, Greece); Thanasis Loukopoulos (Technological Educational Institute of Lamia, Greece); S
    Recent embedded middleware initiatives enable the structuring of an application as a set of collaborating agents deployed in the various sensing/actuating entities of the system. Of particular importance is the incurred cost due to agent communication which in terms depends on agent positions in the system. In this paper we present GRAL a grouping algorithm that migrates groups of agents with the aim of minimizing communication. The algorithm works in a distributed fashion based on knowledge available locally at each node and can be used both for one-shot initial application deployment and for the continuous updating of agent placement. Through simulation experiments under various scenarios we evaluate the algorithm, comparing the solution quality reached against the optimal obtained from exhaustive search.
  • Vitis: A Gossip-based Hybrid Overlay for Internet-scale Publish/Subscribe Enabling Rendezvous Routing in Unstructured Overlay Networks Authors: Fatemeh Rahimian (KTH - Royal Institute of Technology, Sweden); Sarunas Girdzijauskas (Swedish Institute of Computer Science (S
    Peer-to-peer overlay networks are attractive solutions for building Internet-scale publish/subscribe systems. However, scalability comes with a cost: a message published on a certain topic often needs to traverse a large number of uninterested (unsubscribed) nodes before reaching all its subscribers. This might sharply increase resource consumption for such relay nodes (in terms of bandwidth transmission cost, CPU, etc) and could ultimately lead to rapid deterioration of the system’s performance once the relay nodes start dropping the messages or choose to permanently abandon the system. In this paper, we introduce Vitis, a gossip-based publish/subscribe system that signi?cantly decreases the number of relay messages, and scales to an unbounded number of nodes and topics. This is achieved by the novel approach of enabling rendezvous routing on unstructured overlays. We construct a hybrid system by injecting structure into an otherwise unstructured network. The resulting structure resembles a navigable small-world network, which spans along clusters of nodes that have similar subscriptions. The properties of such an overlay make it an ideal platform for ef?cient data dissemination in large-scale systems. We perform extensive simulations and evaluate Vitis by comparing its performance against two base-line publish/subscribe systems: one that is oblivious to node subscriptions, and another that exploits the subscription similarities. Our measurements show that Vitis signi?cantly outperforms the base-line solutions on various subscription and churn scenarios, from both synthetic models and real-world traces.
  • Moving the Code to the Data - Dynamic Code Deployment using ActiveSpaces Authors: Ciprian Docan (Rutgers, The State University of New Jersey, USA); Manish Parashar (Rutgers, The State University of New Jersey,
    Managing the large volumes of data produced by emerging scienti?c and engineering simulations running on leadership-class resources has become a critical challenge. The data has to be extracted off the computing nodes and transported to consumer nodes so that it can be processed, analyzed, visualized, archived, etc. Several recent research efforts have addressed datarelated challenges at different levels. One attractive approach is to of?oad expensive I/O operations to a smaller set of dedicated computing nodes known as a staging area. However, even using this approach, the data still has to be moved from the staging area to consumer nodes for processing, which continues to be a bottleneck. In this paper, we investigate an alternate approach, namely moving the data-processing code to the staging area rather than moving the data. Speci?cally, we present the ActiveSpaces framework, which provides (1) programming support for de?ning the data-processing routines to be downloaded to the staging area, and (2) run-time mechanisms for transporting binary codes associated with these routines to the staging area, executing the routines on the nodes of the staging area, and returning the results. We also present an experimen- tal performance evaluation of ActiveSpaces using applications running on the Cray XT5 at Oak Ridge National Laboratory. Finally, we use a coupled fusion application work?ow to explore the trade-offs between transporting data and transporting the code required for data processing during coupling, and we characterize the sweet spots for each option.