Worst case timing analysis for real-time programs

Real time software is increasingly used in safety critical embedded systems. For these real time systems, tasks have timing requirements (i.e., deadlines) that must be met for correct operation. Various scheduling algorithms have been proposed to guarantee task deadlines based on the worst case execution time of each task. Obviously, the worst case execution time of a task is of significant importance for the construction and verification of a real time system. The paper discusses the problems and solutions related to accurate and safe estimation of worst case execution for real time programs. Issues covered include caches, pipelines and task block by synchronization. The paper also presents a timing tool and some experimental results of estimation of worst case execution time