风险驱动的安全关键实时任务调度  

Risk-driven Scheduling Mechanism for Security-critical Real Time Tasks

作　　者：江维[1] 桑楠[1] 常政威[1] 熊光泽[1] 

机构地区：[1]电子科技大学计算机科学与工程学院,四川成都610054

出　　处：《航空学报》2009年第12期2371-2379,共9页Acta Aeronautica et Astronautica Sinica

基　　金：国家"863"计划(2006AA01Z173;2007AA01Z131)

摘　　要：安全关键系统面临着日趋严峻的安全威胁,如何降低安全关键实时应用的风险成为挑战。通过结合风险评估与实时调度,给出一种风险驱动的任务调度方案。在分析非周期实时任务可调度性的基础上,提出一种基于处理器瞬态利用率、系统安全风险最小的在线调度近似算法。在不违背关键任务的时间约束和安全约束的前提下,该算法能够在低时间复杂度内得到安全性能确保的次优解。实验结果显示所提算法能明显降低安全关键实时应用的风险。具体来讲,最大安全风险可降低22.2%,并且在安全风险近似率上界为110%情况下,真实近似率最小为102.4%。Security-critical systems tend to be subjected to much more serious security threats,therefore it poses a great challenge to reduce the risk of security-critical applications.This article proposes a risk-driven task scheduling mechanism by incorporating risk assessment with real time scheduling.Based on the concept of synthetic utilization of aperiodic tasks,an online task scheduling algorithm is designed to schedule security-sensitive aperiodic tasks with minimal security risk.This algorithm is an approximate algorithm, which can yield security performance guaranteed near-optimal solution in low time complexity without violating the securitycritical and time-critical constraints of tasks. Simulation results show that the proposed algorithm can significantly reduce the risk of security-critical real time applications and satisfy the bound of risk approximation ratio. Specifically, maximal security risk reduction of up to 22.2% is achieved, and minimal approximation ratio of security risk can decrease to 102.4% for the bound of 110%.

关 键 词：安全关键 风险 实时系统 非周期任务 调度算法 

分 类 号：V557.1[航空宇航科学与技术—人机与环境工程] TP309[自动化与计算机技术—计算机系统结构]