Description of execution time dynamics for a set of concurrent real-time tasks

A Real-time System (RTS) implemented in a digital computer interacts with the physical world through knowledge variables (sensors, actuators, Analogical-Digital, and Digital-Analogical convertors) processing its requirements through real-time tasks (J _i: i∈Z ₊). Each J _i is formed by a set of instances {j _i,k: _i,k∈Z ₊, i is the task index, k is the instance index} with at least three time constraints: arrival, execution and, interval times (L _i,k, C _i,k, D _i,k). The execution time identification _Ĉi,k, is based on Instrumental Variable parameter estimation and the recursive state space ARMA model. The execution times were measured experimentally using a Real-time Operative System QNX 6.5 Neutrino in an Intel Core i7 processor with a speed of 2.66 GHz. This paper presents a state of the art real-time task model, execution time measurements, an Instrumental Variable parameter estimator on recursive state space identification, experimentation and, results.