Simulation analysis of real-time task scheduling

In a distributed real-time command, control and communication (C/sup 3/) system, tasks execute to fulfil both local and system-wide computational goals. Satisfying system-wide goals imposes requirements on local tasks to operate in a predictable manner, within restricted timing ranges. In addition, local tasks themselves may vary within a wide operational envelope in terms of their criticalities of performance. Traditional solutions to scheduling use mechanisms such as FIFO, round-robin, or simple priority, to provide sequencing. These techniques are not adequate in a time-constrained environment, where failure could lead to catastrophic results. This paper surveys a collection of scheduling algorithms and examines their performance via simulation for a class of real-time C/sup 3/ tasks. Our valve-phase-deadline (VPD) algorithm is described and analyzed against five well-known schedulers.<>