指令预取感知的多核系统WCRT和WCEC优化  

Instruction-prefetching-aware WCRT and WCEC Optimization in Multicore

作　　者：韩丽艳[1] 安立奎[2] HAN Li-yan;AN Li-kui(School of Information Science and Technology,Bohai University,Jinzhou 121013,China;School of Mathematics and Physics,Bohai University,Jinzhou 121013,China)

机构地区：[1]渤海大学信息科学与技术学院,辽宁锦州121013 [2]渤海大学数理学院,辽宁锦州121013

出　　处：《计算机技术与发展》2020年第9期82-87,共6页Computer Technology and Development

基　　金：辽宁省科技项目(20180550691)。

摘　　要：对嵌入式多核下的实时系统,为了保证任务的可调度性和可靠性,最坏情况下的性能是一个优先考虑的问题,同时对于能量供应有限制的多核系统,最坏情况下的能量消耗也是一个非常关键的问题。顺序指令预取可以提高实时任务的最坏情况下的性能,但对于实时系统中多个不同的子任务,多个子任务采用相同指令预取度不利于提高指令预取在最坏情况下的性能和能量效率。文中利用缓存划分技术消除实时系统中多个子任务在共享缓存上的干扰,提出了支持指令预取的WCRT(worst-case response time)和WCEC(worst-case energy consumption)优化模型,并设计了优化算法。该算法通过建立任务图调整实时系统中子任务的指令预取度,在最小化系统WCRT的基础上,减少系统的WCEC。实验对DEBIE系统进行实例分析,结果表明优化算法在保证实时系统WCRT最小的情况下,其WCEC减少了10.8%。For the real-time system in embedded multicore,in order to guarantee the task schedulability and the reliability,the worst-case performance is a prior to be considered.At the same time for multicore system with limited energy supply,the worst-case energy consumption is also a critical problem.Sequent instruction prefetching can improve the worst-case performance of real-time tasks,but using the same instruction prefetching degree for multiple different subtasks is not beneficial to improve the worst-case performance efficiency and energy efficiency of instruction prefetching.In this paper,cache partitioning technology is used to eliminate interferences of multiple real-time subtasks on the shared cache,and the WCRT(worst-case response time)and WCEC(worst-case energy consumption)optimization model and algorithms with instruction prefetching are designed.The algorithm adjusts instruction prefetching degrees of real-time subtasks by establishing the task graph,and reduces the system WCEC on the basis of minimizing system WCRT.DEBIE system is analyzed in experiment to show that the optimal algorithm can reduce the cache WCEC by 10.8%under the condition that the WCRT of real-time system is kept to a minimum.

关 键 词：多核实时系统 WCRT WCEC 指令预取度 缓存划分 

分 类 号：TP314[自动化与计算机技术—计算机软件与理论]