Hybrid Metaheuristic Approach for Scheduling of Aperiodic OS Tasks - Complex System Modelling and Control Through Intelligent Soft Computations - page 842

Fig. 2 The simulation with polling server and background server

they have the drawback that the average wait and response times for these algo-
rithms can be long, especially for background processing. Figure 1 illustrates the
operation of background and polling aperiodic service using the periodic task set
presented in the table of the same picture (Fig. 1 ).

4.2.2 Motivating Example

Let us suppose a real-time embedded system Sys1 to be initially implemented by 2
characterized tasks as shown in Fig. 1 . These tasks are feasible because the pro-
cessor utilization factor U ¼ 0 : 7 1. These tasks should meet all required deadlines

de ned in user requirements and we have Feasibility ð Current Sys1 ð t ÞÞ True.

Fig. 3 The simulation with deferrable server and background server