NETWORK CONSCIOUS DESIGN OF DISTRIBUTED REAL-TIME SYSTEMS

In this paper, we present a network conscious approach to designing di stributed real-time systems. Given a task graph design of the system, the end-to-end constraints on the inputs and outputs, and the task all ocation on a given distributed platform, we automatically generate tas k attributes (e.g., periods and deadlines) such that (i) the task set is schedulable, and (ii) the end-to-end constraints are satisfied. The method works by first transforming the end-to-end constraints into a set of intermediate constraints on task attributes, and then solving t he intermediate constraints. The complexity of constraint solving is t ackled by reducing the problem into more tractable parts, and then sol ving each subproblem using heuristics to enhance schedulability. The m ethodology presented in this process can be mostly automated, and prov ides useful feedback to a designer when it fails to find a solution. W e expect that the techniques presented in this paper will help reduce the laborious process of designing a real-time system, by bringing res ource contention and schedulability aspects early into the design proc ess. (C) 1998 Elsevier Science B.V. All rights reserved.