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125
Algorithms for Scalable Synchronization on SharedMemory Multiprocessors
 ACM Transactions on Computer Systems
, 1991
"... Busywait techniques are heavily used for mutual exclusion and barrier synchronization in sharedmemory parallel programs. Unfortunately, typical implementations of busywaiting tend to produce large amounts of memory and interconnect contention, introducing performance bottlenecks that become marke ..."
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Cited by 508 (31 self)
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Busywait techniques are heavily used for mutual exclusion and barrier synchronization in sharedmemory parallel programs. Unfortunately, typical implementations of busywaiting tend to produce large amounts of memory and interconnect contention, introducing performance bottlenecks that become markedly more pronounced as applications scale. We argue that this problem is not fundamental, and that one can in fact construct busywait synchronization algorithms that induce no memory or interconnect contention. The key to these algorithms is for every processor to spin on separate locallyaccessible ag variables, and for some other processor to terminate the spin with a single remote write operation at an appropriate time. Flag variables may be locallyaccessible as a result of coherent caching, or by virtue of allocation in the local portion of physically distributed shared memory. We present a new scalable algorithm for spin locks that generates O(1) remote references per lock acquisition, independent of the number of processors attempting to acquire the lock. Our algorithm provides reasonable latency in the absence of contention, requires only a constant amount of space per lock, and requires no hardware support other than
A Mutual Exclusion Algorithm for Ad Hoc Mobile Networks
 Wireless Networks
, 1998
"... A faulttolerant distributed mutual exclusion algorithm which adjusts to node mobility is presented, along with proof of correctness and simulation results. The algorithm requires nodes to communicate with only their current neighbors, making it wellsuited to the ad hoc environment. Experimental ..."
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Cited by 48 (3 self)
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A faulttolerant distributed mutual exclusion algorithm which adjusts to node mobility is presented, along with proof of correctness and simulation results. The algorithm requires nodes to communicate with only their current neighbors, making it wellsuited to the ad hoc environment. Experimental results indicate that adaptation to mobility can improve performance over that of similar nonadaptive algorithms when nodes are mobile.
Greedy Heuristics and an Evolutionary Algorithm for the BoundedDiameter Minimum Spanning Tree Problem
 Proceedings of the 2003 ACM Symposium on Applied Computing
, 2003
"... bound D, the boundeddiameter minimum spanning tree problem seeks a spanning tree on G of lowest weight in which no path between two vertices contains more than D edges. This problem is NPhard for 4 1, where n is the number of vertices in G. An existing greedy heuristic for the problem, called ..."
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Cited by 35 (13 self)
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bound D, the boundeddiameter minimum spanning tree problem seeks a spanning tree on G of lowest weight in which no path between two vertices contains more than D edges. This problem is NPhard for 4 1, where n is the number of vertices in G. An existing greedy heuristic for the problem, called OTTC, is based on Prim's algorithm. OTTC usually yields poor results on instances in which the triangle inequality approximately holds; it always uses the lowestweight edges that it can, but such edges do not in general connect the interior nodes of lowweight boundeddiameter trees. A new randomized greedy heuristic builds a boundeddiameter spanning tree from its center vertex or vertices. It chooses each next vertex at random but attaches the vertex with the lowestweight eligible edge. This algorithm is faster than OTTC and yields substantially better solutions on Euclidean instances. An evolutionary algorithm encodes spanning trees as lists of their edges, augmented with their center vertices. It applies operators that maintain the diameter bound and always generate valid o#spring trees. These operators are e#cient, so the algorithm scales well to larger problem instances. On 25 Euclidean instances of up to 1 000 vertices, the EA improved substantially on solutions found by the randomized greedy heuristic.
Impact of Mobility on Distributed Computations
 Operating Systems Review
, 1993
"... this paper, we have used the terms mobile and portable computing interchangeably. However, strictly speaking, we view portable computing as a more restrictive form of mobile computing: though a portable computer may connect to the network from different locations, it essentially connects to the netw ..."
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Cited by 34 (2 self)
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this paper, we have used the terms mobile and portable computing interchangeably. However, strictly speaking, we view portable computing as a more restrictive form of mobile computing: though a portable computer may connect to the network from different locations, it essentially connects to the network at any given access point through an individual wired connection and therefore, cannot simultaneously move and maintain its connection to the network. The notion of a "cell" and the associated wireless communication with a broadcast capability, is absent from portable computing.
Distributed transactional memory for metricspace networks
 In Proc. International Symposium on Distributed Computing (DISC 2005
, 2005
"... Abstract. Transactional Memory is a concurrent programming API in which concurrent threads synchronize via transactions (instead of locks). Although this model has mostly been studied in the context of multiprocessors, it has attractive features for distributed systems as well. In this paper, we con ..."
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Cited by 18 (0 self)
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Abstract. Transactional Memory is a concurrent programming API in which concurrent threads synchronize via transactions (instead of locks). Although this model has mostly been studied in the context of multiprocessors, it has attractive features for distributed systems as well. In this paper, we consider the problem of implementing transactional memory in a network of nodes where communication costs form a metric. The heart of our design is a new cachecoherence protocol, called the Ballistic protocol, for tracking and moving uptodate copies of cached objects. For constantdoubling metrics, a broad class encompassing both Euclidean spaces and growthrestricted networks, this protocol has stretch logarithmic in the diameter of the network. 1
A Distributed KMutual Exclusion Algorithm
 In Proceedings of the 15th International Conference on Distributed Computing Systems
, 1994
"... This report presents a tokenbased Kmutual exclusion algorithm. The algorithm uses K tokens and a dynamic forest structure for each token. This structure is used to forward token requests. The algorithm is designed to minimize the number of messages and also the delay in entering the critical se ..."
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Cited by 17 (0 self)
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This report presents a tokenbased Kmutual exclusion algorithm. The algorithm uses K tokens and a dynamic forest structure for each token. This structure is used to forward token requests. The algorithm is designed to minimize the number of messages and also the delay in entering the critical section, at low as well as high loads.
A Performance Comparison of Fast Distributed Synchronization Algorithms
 In International Conference on Parallel Processing
, 1994
"... Distributed synchronization is an essential component of parallel and distributed computing. Several fast and lowoverhead distributed synchronization algorithms have been proposed. Each of these algorithms required O(log n) messages per critical section entry and O(log n) bits of storage per proces ..."
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Cited by 15 (1 self)
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Distributed synchronization is an essential component of parallel and distributed computing. Several fast and lowoverhead distributed synchronization algorithms have been proposed. Each of these algorithms required O(log n) messages per critical section entry and O(log n) bits of storage per processor. Asymptotic performance estimates do not proclaim any of the algorithms to be a winner, but no performance comparison of the algorithms has yet been performed. In this paper, we make a comparative performance study of four distributed semaphore algorithms. Each of these algorithms represents a different approach to maintaining distributed information. Since the algorithms we study are the basis for distributed synchronization, distributed virtual memory, coherent caches, and distributed object systems, our results have implications about the best methods for their implementation. We find that the distributed synchronization algorithm of Chang, Singhal, and Liu has the overall best perfor...
Variable neighborhood search for the bounded diameter minimum spanning tree problem
 Proceedings of the 18th Mini Euro Conference on Variable Neighborhood Search
, 2005
"... The bounded diameter minimum spanning tree problem is an NPhard combinatorial optimization problem with applications in various fields like communication network design. We propose a general variable neighborhood search approach for it, utilizing four different types of neighborhoods. They were d ..."
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Cited by 14 (9 self)
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The bounded diameter minimum spanning tree problem is an NPhard combinatorial optimization problem with applications in various fields like communication network design. We propose a general variable neighborhood search approach for it, utilizing four different types of neighborhoods. They were designed in a way enabling an efficient incremental evaluation and search for the best neighboring solution. An experimental comparison on instances with complete graphs with up to 1000 nodes indicates that this approach consistently outperforms the so far leading evolutionary algorithms with respect to solution quality and computation time.
Efficacy of floor control protocols in distributed multimedia collaboration
 CLUSTER COMPUTING
, 1999
"... Distributed multipoint applications for group interaction across widearea networks, such as for simulation and telecollaboration, are becoming increasingly popular. While reliable multicasting has made significant advances in recent years, effective mechanisms to synchronize and coordinate work wit ..."
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Cited by 13 (2 self)
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Distributed multipoint applications for group interaction across widearea networks, such as for simulation and telecollaboration, are becoming increasingly popular. While reliable multicasting has made significant advances in recent years, effective mechanisms to synchronize and coordinate work within large multicast groups and across long distances are still lacking. Synchronous sharing of resources, whose operational semantics prohibits parallel usage, typically creates race conditions among users, which can be resolved through an access discipline called floor control. Existing solutions on floor control, implemented either at the session or application layer, are mostly proprietary, limited in scope and not scalable. Furthermore, no performance comparison of floor control protocols has been attempted to date. We present a novel taxonomy and comparative performance analysis of known classes of floor control protocols, ranging from socially mediated control to protocols operating on ring and tree topologies. We find that aggregation and selective transmission of control information in a tree structure is the most promising solution with regard to scalability, efficacy, and robustness. The principal operation of such a tree protocol is outlined, which dynamically organizes participants in a multilevel control tree and aggregates resource sharing directives on the paths between interacting stations.