  In this paper we propose to quantify execution time variability of programs
using statistical dispersion parameters. We show how the execution time
variability can be exploited in mixed criticality real-time systems. We propose
a heuristic to compute the execution time budget to be allocated to each low
criticality real-time task according to its execution time variability. We show
using experiments and simulations that the proposed heuristic reduces the
probability of exceeding the allocated budget compared to algorithms which do
not take into account the execution time variability parameter.
