# Reducing Dynamic Power Consumption in Mixed-Critical Real-Time Systems
## 2 Related Work and Problem Description  
Initially, an MC system is considered by Vestal [8] for scheduling and since then it has gained increasing interest in real-time scheduling. [PERSON] and [PERSON] consider [9] the mixed-criticality system in a way that all LO-criticality jobs are discarded when the system mode switches to HI-criticality [10; 11; 12]. In [13], they showed that the scheme of Vestal is optimal for fixed-priority scheduling systems. In [14], they provided response-time analysis of mixed-criticality tasks in order to increase the schedulability of fixed-priority tasks. In [10], they provided a heuristic scheduling algorithm based on Audsley priority assignment strategy for efficient scheduling. Audsley approach [15] is used to assign priority from the lowest to highest level. At each priority level, the lowest priority job from the low criticality task set is tried first, if it is schedulable then the job moves up to the next priority level if it is schedulable, then the lowest search can be abandoned as the task set is unscheduled. In [16], they considered how these time-triggered tables can be produced via first simulation. The energy-minimization consumption of a processor is generally classified into dynamic and static techniques in terms of the consideration of dynamic frequency adjustment. They are also classified into continuous or discrete frequency level schemes according to the assumption of frequency continuity. [PERSON] et al. [17] and [PERSON] et al. [18] also proposed a static (or offline) scheduling method to reduce energy minimization in a real-time system, in this paper [19] [PERSON] and [PERSON] study the energy saving of a periodic real-time job. [PERSON] determined proposed stochastic data to derive a energy-efficient schedules scheme in [20]. In [21], they provided minimum power consumption in periodic task scheduling for discrete frequency-level systems. On the contrary, the dynamic scheduling scheme adjusts the CPU frequency or speed levels depending on the current system load in order to fully utilized the CPU slack time. The Audsley scheme for assigning priority to mixed-criticality jobs is based on their criticality level in this paper [15], and priority is given to jobs manner high to low scheduling priorities so that priorities are given to lowest priorities task, the schedule difficulty of the MC real-time system is investigated by [PERSON], the author proof when all jobs are released at the same time is when these jobs are set to NP-complete [9]. In this scheme, they investigated the optimal schedule algorithm for the MC system scheduling performing well in practice. The own criticality base priority (OCBP) to MC sporadic jobs by [PERSON] and [PERSON] [22] considers criticality for priority assignment. When a new job arrives to the system, a new priority is assigned to the job. In [3], they presented a scheduling scheme known as priority-list reuse scheduling based on the OCBP scheduler. In [23], they assumed a likewise realistic energy model and presented an optimal static scheme for minimizing the energy of multi-component with adjusting individual frequencies main memory and processor system bus. The connection between multiple-choice knap sack problem (MCKP) and dynamic voltage scaling (DVS) for periodic task and energy optimization was at first proven by [PERSON] and [PERSON] [24]. In this paper [PERSON] et al. consider [18] the dynamic voltage frequency scaling scheme for periodic jobs that complete before their worst-case execution times (WCETs). In [25], they proposed the elastic scheduling for the purpose of utilizing CPU with discrete frequencies. In [26], they presented a dynamic slack algorithm allocation for real time that consider both the loss energy minimization and frequency scaling overhead. The cycle conservation approach was proposed by [PERSON] et al. [27]. They suggested a novel power aware scheduling scheme named cycle conservation DVFS for sporadic jobs.