Measurement of extreme execution times for software

The most important analytical method to assure the quality of real-time systems is dynamic testing aimed at checking the functional correctness of the software. Dynamic aspects like the duration of computations, the memory actually needed, or the synchronisation of parallel processes are also of major importance for the correct function of real-time systems and must be tested. We have used genetic algorithms to search for test input data that causes extreme execution time paths. Experiments on a number of programs with up to 1511 LOC and 843 integer input parameters have successfully identified new longer and shorter paths than had been found using random testing and systematic testing. Genetic algorithms are able therefore to check large programs and they show considerable promise in establishing the validity of the temporal behaviour of real-time software