Deadline Assignment in a Distributed Soft Real-Time System

Ben Kao, Hector Garcia-Molina

Abstract: In a distributed environment, tasks often have processing demands on multiple sites. A distributed task is usually divided up into several subtasks, each one to be executed at some site in order. In a real-time system, an overall deadline is usually specified by an application designer indicating when a distributed task is to be finished. To study the subtask deadline assignment problem a simple model of the system and tasks is postulated. The focus is on soft real-time systems. In such systems, it is very difficult to guarantee that all deadlines will be met, and hence one tries to minimize the number of deadlines that are missed. The authors examine (through simulations) four strategies for subtask deadline assignment in a distributed soft real-time environment.<