Hybrid algorithms for independent batch scheduling in grids

Grid computing has emerged as a wide area distributed paradigm for solving large-scale problems in science, engineering, etc. and is known as the family of eScience grid-enabled applications. Computing planning of incoming jobs efficiently with available machines in the grid system is the main requirement for optimised system performance. One version of the problem is that of independent batch scheduling, in which jobs are assumed to be independent and are scheduled in batches aimed at minimising the makespan and flowtime. Given the hardness of the problem, heuristics are used to find high quality solutions for practical purposes of designing efficient grid schedulers. Recently, considerable efforts were spent in implementing and evaluating not only stand-alone heuristics and meta-heuristics, but also their hybridisation into even higher level algorithms. In this paper, we present a study on the performance of two popular algorithms for the problem, namely Genetic Algorithms (GAs) and Tabu Search (TS) and two hybridisations involving them, namely, the GA (TS) and GA-TS, which differ in the way the main control and cooperation among GA and TS are implemented. The hierarchic and simultaneous optimisation modes are considered for the bi-objective scheduling problem. Evaluation is done using different grid scenarios generated by a grid simulator. The computational results showed that the hybrid algorithm outperforms both the GA and TS for the makespan parameter, but not for the flowtime parameter.Peer ReviewedPostprint (author's final draft

Effcient Scheduling Heuristics for Independent Tasks in Computational Grids

Grid computing is an extension to parallel and distributed computing. It is an emerging environment to solve large scale complex problems. It enables the sharing, coordinating and aggregation of computational machines to full the user demands. Computational grid is an innovative technology for succeeding generations. It is a collection of machines which is geographically distributed under different organisations. It makes a heterogeneous high performance computing environment. Task scheduling and machine management are the essential component in computational grid. Now a day, fault tolerance is also playing a major role in computational grid. The main goal of task scheduling is to minimize the makespan and maximize the machine utilisation. It is also emphasis on detection and diagnosis of fault. In computational grid, machines may join or leave at any point of time. It may happen that machine is compromised by an advisory or it may be faulty due to some unavoidable reason like power failure, system failure, network failure etc. In this thesis, we address the problem of machine failure and task failure in computational grid. Also, we have focused on improving the performance measures in terms of makespan and machine utilisation. A simulation of the proposed heuristics using MATLAB is presented. A comparison of our proposed heuristics with other existing heuristics is conducted. We also demonstrate that number of task completion increases even if some of the machine work efficiently in computational grid