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Parallel and Distributed Systems, IEEE Transactions on

Issue 10 • Date Oct 1998

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Displaying Results 1 - 10 of 10
  • An analytical model for hybrid checkpointing in time warp distributed simulation

    Page(s): 947 - 951
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    The Time Warp distributed simulation algorithm uses checkpointing to save process states after certain event executions for later recovery at the time of a rollback. Two main techniques have been used for checkpointing: periodic state saving and incremental state saving. The former technique introduces large overheads in reconstructing a desired state by coasting forward from an earlier checkpointed state if the computational granularity is large. The latter technique also has large overheads in applications with large rollback distances. A hybrid checkpointing technique is proposed which uses both periodic and incremental state saving simultaneously in such a way that it reduces checkpointing time overheads. A detailed analytical model is developed for the hybrid technique, and comparisons are made using similar analytical models with periodic and incremental state saving techniques. Results show that when the system parameters are chosen to represent large and complex simulated systems, the hybrid approach has less checkpointing time overhead than the other two techniques View full abstract»

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  • Theoretical analysis for communication-induced checkpointing protocols with rollback-dependency trackability

    Page(s): 963 - 971
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    Rollback-Dependency Trackability (RDT) is a property that states that all rollback dependencies between local checkpoints are on-line trackable by using a transitive dependency vector. In this paper, we address three fundamental issues in the design of communication-induced checkpointing protocols that ensure RDT. First, we prove that the following intuition commonly assumed in the literature is in fact false: If a protocol forces a checkpoint only at a stronger condition, then it must take, at most, as many forced checkpoints as a protocol based on a weaker condition. This result implies that the common approach of sharpening the checkpoint-inducing condition by piggybacking more control information on each message may not always yield a more efficient protocol. Next, we prove that there is no optimal on-line RDT protocol that takes fewer forced checkpoints than any other RDT protocol for all possible communication patterns. Finally, since comparing checkpoint-inducing conditions is not sufficient for comparing protocol performance, we present some formal techniques for comparing the performance of several existing RDT protocols View full abstract»

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  • Efficient fault-tolerant multicast scheme for hypercube multicomputers

    Page(s): 952 - 962
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    This paper presents a fault-tolerant multicast scheme for hypercube multicomputers. The method is based on the routing capability information that is stored in each node. In comparison with the previous schemes, this information is able to capture the fault status more precisely. Two multicast algorithms are presented in the paper. These algorithms multicast messages in an attempt to minimize derouting so that time optimality can be achieved. Moreover, the routing capability information is used to guide derouting in an efficient manner when such needs arise. The amount of traffic incurred is addressed in the paper. The hardware design for the algorithms is also discussed. Extensive simulation has been conducted to evaluate the performance of the scheme. The results show the effectiveness of the proposed algorithms View full abstract»

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  • Macro-star networks: efficient low-degree alternatives to star graphs

    Page(s): 987 - 1003
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (580 KB)  

    We propose a new class of interconnection networks, called macro-star networks, which belong to the class of Cayley graphs and use the star graph as a basic building module. A macro-star network can have node degree that is considerably smaller than that of a star graph of the same size, and diameter that is sublogarithmic and asymptotically within a factor of 1.25 from a universal lower bound (given its node degree). We show that algorithms developed for star graphs can be emulated on suitably constructed macro-stars with asymptotically optimal slowdown. This enables us to obtain through emulation a variety of efficient algorithms for the macro-star network, thus proving its versatility. Basic communication tasks, such as the multimode broadcast and the total exchange, can be executed in macro-star networks in asymptotically optimal time under both the single-port and the all-port communication models. Moreover, no interconnection network with similar node degree can perform these communication tasks in time that is better by more than a constant factor than that required in a macro-star network. We show that macro-star networks can embed trees, meshes, hypercubes, as well as star, bubble-sort, and complete transposition graphs with constant dilation. We introduce several variants of the macro-star network that provide more flexibility in scaling up the number of nodes. We also discuss implementation issues and compare the new topology with the star graph and other popular topologies View full abstract»

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  • Parallelization model for successive approximations to the Rayleigh-Ritz linear variational problem

    Page(s): 938 - 946
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    Many of the differential equations arising in science and engineering can be recast in the form of a matrix eigenvalue problem. Solution of this equation within the context of the Rayleigh-Ritz variational method may be viewed as one of the fundamental tasks of numerical analysis. Successive approximation approaches to the Rayleigh-Ritz problem seek to improve eigenvectors and eigenfunctions by sequentially refining a trial function. Parallelization of successive approximation approaches has been demonstrated numerous times in the literature; these studies addressed either the successive approximations or the matrix diagonalization levels of the algorithm. It is shown in this paper that these two strategies may be applied independently of one another, and the advantages of applying both parallelization levels simultaneously to the problem are discussed. Performance estimates for a two-tiered parallelization strategy are obtained by extrapolating from existing published performance data for which the two levels of parallelization were applied separately View full abstract»

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  • Time- and VLSI-optimal sorting on enhanced meshes

    Page(s): 929 - 937
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    Sorting is a fundamental problem with applications in all areas of computer science and engineering. In this work, we address the problem of sorting on mesh connected computers enhanced by endowing each row and each column with its own dedicated high-speed bus. This architecture, commonly referred to as a mesh with multiple broadcasting, is commercially available and has been adopted by the DAP family of multiprocessors. Somewhat surprisingly, the problem of sorting m, (m⩽n), elements on a mesh with multiple broadcasting of size √n×√n has been studied, thus far, only in the sparse case, where m∈Θ(√n) and in the dense case, where m∈ΘO(√n). Yet, many applications require using an existing platform of size √n×√n for sorting m elements, with √n<m⩽n. Our main contribution is to present the first known adaptive time- and VLSI-optimal sorting algorithm for meshes with multiple broadcasting. Specifically we show that, for every choice of a constant 0<ε⩽½, it is possible to sort m elements, n½+ε⩽m⩽n, stored in the leftmost [m/√n] columns of a mesh with multiple broadcasting of size √n×√n in Θ(m/√n) time View full abstract»

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  • Critical path profiling of message passing and shared-memory programs

    Page(s): 1029 - 1040
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    We introduce a runtime, nontrace-based algorithm to compute the critical path profile of the execution of message passing and shared-memory parallel programs. Our algorithm permits starting or stopping the critical path computation during program execution and reporting intermediate values. We also present an online algorithm to compute a variant of critical path, called critical path zeroing, that measures the reduction in application execution time that improving a selected procedure will have. Finally, we present a brief case study to quantify the runtime overhead of our algorithm and to show that online critical path profiling can be used to find program bottlenecks View full abstract»

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  • Diskless checkpointing

    Page(s): 972 - 986
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    Diskless Checkpointing is a technique for checkpointing the state of a long-running computation on a distributed system without relying on stable storage. As such, it eliminates the performance bottleneck of traditional checkpointing on distributed systems. In this paper, we motivate diskless checkpointing and present the basic diskless checkpointing scheme along with several variants for improved performance. The performance of the basic scheme and its variants is evaluated on a high-performance network of workstations and compared to traditional disk-based checkpointing. We conclude that diskless checkpointing is a desirable alternative to disk-based checkpointing that can improve the performance of distributed applications in the face of failures View full abstract»

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  • Bound performance models of heterogeneous parallel processing systems

    Page(s): 1041 - 1056
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Systems of heterogeneous parallel processing are studied such as arising in parallel programs executed on distributed systems. A lower and an upper bound model are suggested to obtain secure lower and upper bounds on the performance of these systems. The bounding models are solved by using a matrix-geometric algorithmic approach. Formal proofs of the bounds are provided along with error bounds on the accuracy of the bounds. These error bounds in turn are reduced to simple computational expressions. Numerical results are included. The results are of interest for application to arbitrary fork-join models with parallel heterogeneous processors and synchronization View full abstract»

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  • Efficient broadcast and multicast on multistage interconnection networks using multiport encoding

    Page(s): 1004 - 1028
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    This paper proposes anew approach for implementing fast multicast and broadcast in unidirectional and bidirectional multistage interconnection networks (MINs) with multiport encoded multidestination worms. For a MIN with n stages, such worms use n header flits each. One flit is used for each stage of the network and it indicates the output ports to which a multicast message needs to be replicated. A multiport encoded worm with (d1, d2..., dn, 1⩽di⩽k) degrees of replication for the respective stages is capable of covering (d1×dx×...×dn) destinations with a single communication start-up. In this paper, a switch architecture is proposed for implementing multidestination worms without deadlock. Three grouping algorithms of varying complexity are presented to derive the associated multiport encoded worms for a multicast to an arbitrary set of destinations. Using these worms, a multinomial tree-based scheme is proposed to implement the multicast. This scheme significantly reduces broadcast/multicast latency compared to schemes using unicast messages. Simulation studies for both unidirectional and bidirectional MIN systems indicate that improvement in broadcast/multicast latency up to a factor of four is feasible using the new approach. Interestingly, this approach is able to implement multicast with reduced latency as the number of destinations increases beyond a certain number. Compared to implementing unicast messages, this approach requires little additional logic at the switches. Thus, the scheme demonstrates significant potential for implementing efficient collective communication operations on current and future MIN-based systems View full abstract»

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Aims & Scope

IEEE Transactions on Parallel and Distributed Systems (TPDS) is published monthly. It publishes a range of papers, comments on previously published papers, and survey articles that deal with the parallel and distributed systems research areas of current importance to our readers.

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Meet Our Editors

Editor-in-Chief
David Bader
College of Computing
Georgia Institute of Technology