Presentation on theme: "Messages Complexity Evaluation For Dijkstra-Scholton and Shavit-Francez Termination Detection Algorithms Kovan A. Mohammed Ali Advanced Operating System."— Presentation transcript:
Messages Complexity Evaluation For Dijkstra-Scholton and Shavit-Francez Termination Detection Algorithms Kovan A. Mohammed Ali Advanced Operating System Fall 2013 Kent State University
Abstract Of Presentation The Dijkstra-Scholton and Shavit-Francez are algorithms for detecting termination in Distributed Systems. Which both are explicit termination or proper termination, all processes are aware of the termination. In this presentation, I tried to compare massages complexity of both algorithms in fully connected topology with two experiments.
INTRODUCTION The implicit termination algorithms are messages termination. The explicit termination is a processes termination. Dijkstra-Scholton algorithm is for centralized (diffusing) computations. The Shavit-Francez Algorithm generalized the Dijkstra- Scholton algorithm to be a decentralized algorithm. Two type of messages: MSG & SIG plus messages for Wave algorithm.
E XPERIMENTAL S ETUP I tried to run both algorithms, Dijkstra-Scholton and Shavit- Francez in two different experiments of fully connected topology. I started with 5 processes and increased the number of the processes by 5 in each step. Also, I differ the number of initiators 5 to 50. In the first experiment: I used Gossip-based topology In second experiment: I used randomly flood on fully connected topology.
CODE I coded with C++. I worked on MacBook and used Xcode 5.0.2 I faced some problems at first with the Basic algorithms that keep sending messages. But I solve this problem by using guarded-commands. I waited almost 3 hours for 1000 runs on random flood that never finished, after that, I realized that I typed one extra zero.
FUTURE WORK Run both algorithms in different topologies. Run with more processes and more initiators. Too many messages been sent during run time of algorithms. Improve both algorithms to be more efficient. By decreasing the number of initiators with random flood the message complexity also decreased. Therefore, needs more research.
R EFERENCES Edsger W. Dijkstra, C. S. Scholten “Termination Detection for Diffusing Computations” 1980. Nir Shavit, Nissim Francez “A new approach to detection of locally indicative stability” 1986. Gerard Tel “Introduction to Distributed Algorithms”, Cambridge University Press, 2nd edition, 2000.