Booting Time Minimization for Real-Time Embedded Systems with Non-Volatile Memory

Minimizing the booting time of an embedded system has become a major technical issue for the success of many consumer electronics. In this paper, the booting time minimization problem for real-time embedded systems with the joint consideration of DRAM and non-volatile memory is formally formulated. We show this is an ${\cal NP}$-hard problem, and propose an optimal but pseudo-polynomial-time algorithm with dynamic programming techniques. In considering polynomial-time solutions, a $0.25$-approximation greedy algorithm is provided, and a polynomial-time approximation scheme is developed to trade the optimality of the derived solution for the time complexity according to a user-specified error bound. The proposed algorithms can manage real-time embedded systems consisting of not only real-time tasks, but also initialization tasks that are executed only once during system booting. The proposed algorithms were then evaluated with $65$ real benchmarks from the MRTC and DSPstone benchmark suites, and the results showed that all of the proposed algorithms can reduce booting time for each benchmark set by more than 29 percent. Moreover, extensive simulations were conducted to show the capability of the proposed approaches when used with various hardware resources and software workloads.