Scheduling stochastic tasks with precedence constrain on cluster systems with heterogenous communication architecture

Abstract

Scheduling precedence constrained stochastic tasks on heterogenous cluster systems is an important issue which impact the performance of clusters significantly. Different with deterministic tasks, stochastic task model assumes that the workload of task and quantity of data transmission between tasks are stochastic variables, which is more realistic than other task models. Scheduling model and algorithms of precedence constrained stochastic tasks attract a large number of researchers’ attention recently. An algorithm SDLS (Stochastic Dynamic Level Scheduling) has been proved performing well in scheduling stochastic tasks on heterogenous clusters. However, the assumption about communication time between tasks in SDLS is much simpler than its assumptions about task computing time, which makes it cannot depict the communication cost among heterogenous links well. In this paper, it is assumed that the quantity of data communication between tasks is a stochastic variable of normal distribution, instead of assuming communication time among heterogenous links a same stochastic variable immediately. Moreover, a modified scheduling model and algorithm SDLS-HC (Stochastic Dynamic Level Scheduling on Heterogenous Communication links) are proposed. Work in this paper focus on considering much more detailed communication cost in task scheduling based on SDLS. Evaluation on many random generated tasks experiments demonstrates that SDLS-HC achieves better performance than SDLS on cluster systems with heterogenous links.