Dynamic Evaluation Methods For Interrupts Driven Software Performance Of Embedded System

Embedded systems have three basic characters:compact limited resources, strict time constraints and extremely sensitive cost. Embedded software needs to deal with a large number of interrupts. Many embedded software performance indexes (such as system throughput, the stack depth), which are closely related to interrupts, are important basis for evaluating software’s quality and guiding system’s design. However, interrupts’uncertainty and dynamic nature make them difficult to test.Focusing on the practical needs of embedded software’s design and security guarantee, this paper does some research based on the embedded software dynamic simulation and verification system. Firstly, an interrupt queuing model with preemptive priority is proposed. By analyzing steady-state features in queuing system, some key performance indexes such as system throughput, interrupt loss rate, average interrupt handling time, interrupt processing time and CPU security occupancy rate in the embedded system can be obtained. Then, GA(Genetic Algorithms), decision trees and STM are used to solve the stack depth test problem. Through analyzing the stack occupancy and interrupt types in detail with the aim of finding the WCSD(Worst Case Stack Depth) execution path, an interrupt scheduling model and a WCSD dynamic test approach based on GA are put forward to reduce the test error. Finally, this paper studies more stable WCSD test methods, proposes a multi-tier interrupt superposition model through analyzing stack occupancy distribution along with the program instruction sequences, and gets a more accurate the stack depth upper bound of embedded software.Besides, by integrating these research achievements to SPARC simulator, an all-digital simulation verification platform for embedded system is set up to evaluate software’s key performance indexes effectively and improve the security of embedded system. The experimental results show that the theories and methods in this paper have good reliability, feasibility and practical values.