Abstract
The effect of using a simple synchronizer on the performance of a directed, strongly connected, distributed network, is analysed. In this paper we assume that the time of message transmission is positive but negligible. It is shown that the synchronizer is sufficient to assure that a full rate of computation is achieved in networks with a global clock, in spite of the absence of a global start-up signal. In fact,unison is reached within linear time. A similar phenomenon occurs if there is no global clock, but all local clocks have the same rate. In case the local clocks do not have the same rate, it is shown that the computational rate is not slower than anysluggish clock; i.e., a clock such that between any two of its ticks, every local clock ticks at least once.
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References
B. Awerbuch, Complexity of network synchronization,Journal of the Association for Computing Machinery, Vol. 32, No. 4, Oct. 1985, pp. 804–823.
A. Arora, S. Dolev, and M. Gouda, Maintaining digital clocks in step,Parallel Processing Letters, Vol. 1, No. 1, Sept. 1991, pp. 11–18.
K. M. Chandy and L. Lamport, Distributed snapshots: Determining global states of distributed systems,ACM Transactions on Computer Systems, Vol. 3, No. 1, Feb. 1985, pp. 63–75.
F. Commoner, A. W. Holt, S. Even, and A. Pnueli, Marked Directed Graphs,Journal of Computer and System Sciences, Vol. 5, No. 5, Oct. 1971, pp. 511–523.
E. W. Dijkstra, Self-stabilizing systems in spite of distributed control,Communications of the ACM, Vol. 17, No. 11, 1974, pp. 643–644.
S. Even, and S. Rajsbaum, Unison in distributed networks, inSequences, Combinatorics, Compression, Security and Transmission, R. M. Capocelli (ed.), Springer-Verlag, New York, 1990, pp. 479–487.
S. Even, and S. Rajsbaum, The use of a synchronizer yields maximum computation rate in distributed networks,Proceedings of the 22nd Annual ACM Symposium on Theory of Computing, 1990, pp. 95–105. To appear inMathematical Systems Theory.
R. G. Gallager, Distributed Minimum Hop Algorithms, Technical Report LIDS-P-1175, M.I.T., Cambridge, MA, Jan. 1982.
H. J. Genrich, Einfache Nicht-Sequentielle Prozesse, Gesellschaft für Mathematik und Datenverarbeitung, Birlinghoven, Germany, 1970.
M. G. Gouda, and T. Herman, Stabilizing unison,Information Processing Letters, Vol. 35, No. 4, 1990, pp. 171–175.
T. Jiang, The Synchronization of Nonuniform Networks of Finite Automata, Technical Report 89-03, McMaster University, Ontario, 1989. Also inProceedings of the 30th Annual Symposium on Foundations of Computer Science, 1989, pp. 376–381.
E. F. Moore, The firing squad synchronization problem, inSequential Machines, Selected Papers, Addison-Wesley, Reading, MA, 1964, pp. 213–214.
P. Rosenstiehl, J. R. Fiksel, and A. Holliger, Intelligent graphs: Networks of finite automata capable of solving graph problems, inGraph Theory and Computing, R. C. Read (ed.), Academic Press, New York, 1972, pp. 219–265.
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The first author was supported by the Fund for the Promotion of Research at the Technion. The work of the second author was done while he was in the Computer Science Department of the Technion; he is presently visiting the Laboratory for Computer Science, MIT.
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Even, S., Rajsbaum, S. Unison, canon, and sluggish clocks in networks controlled by a synchronizer. Math. Systems Theory 28, 421–435 (1995). https://doi.org/10.1007/BF01185865
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DOI: https://doi.org/10.1007/BF01185865