The Distributed Spanning Tree Structure

International audienceSearch algorithms are a key issue to share resources in large distributed systems as peer networks. Several distributed interconnection structures and algorithms have already been studied in this context. With expanding ring algorithms, the efficiency of searches depends on the topology used to send query requests and on the dynamics of the structure. In this paper, we present an interconnection structure that limits the number of messages needed for search queries. This structure, called Distributed Spanning Tree (DST), defines each node as the root of a spanning tree. So, it behaves as a tree for the number of messages but it balances the load generated by the requests among computers and, thus, it avoids to overload the root~node. This structure is scalable because it only needs a logarithmic memory space per computer to be maintained. A formal and practical description of the structure is presented and we describe traversal algorithms. Simulations show that DST based searches behave better than randomly generated graphs and trees as it generates less messages to query all computers while avoiding the tree bottlenecks

Distributed and Multiprocessor Scheduling

This chapter discusses CPU scheduling in parallel and distributed systems. CPU scheduling is part of a broader class of resource allocation problems, and is probably the most carefully studied such problem. The main motivation for multiprocessor scheduling is the desire for increased speed in the execution of a workload. Parts of the workload, called tasks, can be spread across several processors and thus be executed more quickly than on a single processor. In this chapter, we will examine techniques for providing this facility. The scheduling problem for multiprocessor systems can be generally stated as \How can we execute a set of tasks T on a set of processors P subject to some set of optimizing criteria C? The most common goal of scheduling is to minimize the expected runtime of a task set. Examples of other scheduling criteria include minimizing the cost, minimizing communication delay, giving priority to certain users\u27 processes, or needs for specialized hardware devices. The scheduling policy for a multiprocessor system usually embodies a mixture of several of these criteria. Section 2 outlines general issues in multiprocessor scheduling and gives background material, including issues specific to either parallel or distributed scheduling. Section 3 describes the best practices from prior work in the area, including a broad survey of existing scheduling algorithms and mechanisms. Section 4 outlines research issues and gives a summary. Section 5 lists the terms defined in this chapter, while sections 6 and 7 give references to important research publications in the area

A survey of some aspects of parallel and distributed iterative algorithms

Cover title.Includes bibliographical references (p. 29-33).Research supported by the NSF. ECS-8519058 ECS-8552419 Research supported by the ARO. DAAL03-86-K-0171 Research supported by Bellcore, Du Pont and IBM.Dimitri P. Bertsekas, John N. Tsitsiklis

Parallel and distributed iterative algorithms : a selective survey

Cover title.Includes bibliographical references.Supported by the NSF with matching funds from Bellcore, Inc. and IBM Inc. ECS-8519058 ECS-8552419 Supported by the ARO. DAAL03-86-K-0171Dimitri P. Bertsekas, John N. Tsitsiklis

Keyword-based search in peer-to-peer networks

Ph.DDOCTOR OF PHILOSOPH

High Performance Software Reconfiguration in the Context of Distributed Systems and Interconnection Networks.

Designed algorithms that are useful for developing protocols and supporting tools for fault tolerance, dynamic load balancing, and distributing monitoring in loosely coupled multi-processor systems. Four efficient algorithms are developed to learn network topology and reconfigure distributed application programs in execution using the available tools for replication and process migration. The first algorithm provides techniques for transparent software reconfiguration based on process migration in the context of quadtree embeddings in Hypercubes. Our novel approach provides efficient reconfiguration for some classes of faults that may be identified easily. We provide a theoretical characterization to use graph matching, quadratic assignment, and a variety of branch and bound techniques to recover from general faults at run-time and maintain load balance. The second algorithm provides distributed recognition of articulation points, biconnected components, and bridges. Since the removal of an articulation point disconnects the network, knowledge about it may be used for selective replication. We have obtained the most efficient distributed algorithms with linear message complexity for the recognition of these properties. The third algorithm is an optimal linear message complexity distributed solution for recognizing graph planarity which is one of the most celebrated problems in graph theory and algorithm design. Recently, efficient shortest path algorithms are developed for planar graphs whose efficient recognition itself was left open. Our algorithm also leads to designing efficient distributed algorithm to recognize outer-planar graphs with applications in Hamiltonian path, shortest path routing and graph coloring. It is shown that efficient routing of information and distributing the stack needed for for planarity testing permit local computations leading to an efficient distributed algorithm. The fourth algorithm provides software redundancy techniques to provide fault tolerance to program structures. We consider the problem of mapping replicated program structures to provide efficient communication between modules in multiple replicas. We have obtained an optimal mapping of 2-replicated binary trees into hypercubes. For replication numbers greater than two, we provide efficient heuristic simulation results to provide efficient support for both \u27N-version programming\u27 and \u27Recovery block\u27 approaches for software replication

A bibliography on parallel and vector numerical algorithms

This is a bibliography of numerical methods. It also includes a number of other references on machine architecture, programming language, and other topics of interest to scientific computing. Certain conference proceedings and anthologies which have been published in book form are listed also