The Performance of the Chandy- Mishra Snapshot algorithm Jing Mao Instructor: Mikhail Nesterenko

 Introduction  Experimental Setup  Code Implementation  Results Analysis  Conclusion  Future Work  References Outline

 Chandy Mishra:  Any random process can take snapshot at random time  Snapshot consists of state information about the system and message queue Introduction

 Measuring Performance of the snapshot Algorithms  Time complexity is measured by the number of messages in the longest chain of causally dependent events  Message complexity - number of messages it takes the algorithm to carry out specified task Introduction

 Snapshot algorithms run on top of a basic algorithm.  In this implementation Basic algorithm used is random flooding.  Data points are inserted to count total number of messages forwarded and total Time taken.  Number of processes: (5, 10,15,20, 25, 30,35) Experimental Setup

 The chandy-mishra snapshot algorithm is directly embedded in the class “SimulationEngine”  Randomly pick a process to call snapshot function  Two variables: time_complexity, message_complexity are used to track the total time and message complexity Code implementation

Results Analysis

 As the number of processes grows, both the completion time and the number of messages increase  Time complexity is much larger than messages complexity, the difference becomes more apparently with the increase of the number of the processes Conclusion

 Algorithm implementations needs to be tested on large real distributed systems.  Try different basic algorithms to verify the performance of chandy-mishra snapshot algorithm Future Work

Thanks !

 LAMPORT, L. Time, clocks, and the ordering of events in a distributed system. Commun. ACM 21, 7 (July 1978),  CHANDY, K, LAMPORT, L. Distributed Snapshots: Determining Global States of Distributed Systems. ACM Transactions on Computer Systems, vol 3, no 1, Feb85.  Babaoglu, O, Marzullo, K, Consistent Global States of Distributed Systems: Fundamental Concepts and Mechanisms, Distributed Systems, Sape J. Mullender, Addison-Wesley, Reference