一种面向实时系统的程序基本块指令预取技术  

Basic-Block Based Instruction Prefetching Technology for Real-Time System

作　　者：王恩东 倪璠 陈继承 王洪伟 唐士斌 

机构地区：[1]高效能服务器和存储技术国家重点实验室(浪潮(北京)电子信息产业有限公司),北京100085

出　　处：《软件学报》2016年第9期2426-2442,共17页Journal of Software

基　　金：国家高技术研究发展计划(863)(2013AA011701)~~

摘　　要：面向通用计算机系统的指令预取技术无法满足实时系统的应用需求,其中一个重要原因是:无效预取引起的指令Cache内容污染使得实时任务WCET评估值不够精确,导致系统可调度性下降,严重影响系统效率.以简化实时任务WCET分析、降低任务WCET评估值为目标,提出一种基于程序基本块的指令预取方法.该方法以基本块为粒度执行指令预取,避免了传统指令预取技术引入的无效预取;通过简化最坏情况下的指令访问命中/缺失情况判定,简化任务WCET分析过程并优化WCET评估值.实时基准测试程序评估结果表明:与常规无预取方法相比,该预取方法可使实时任务WCET评估值降低约20%,平均执行情况下的指令Cache访问性能提升约10%.Instruction prefetching technologies proposed for general purpose computer systems cannot meet the requirements of real- time systems. One of the most important issues is that cache content pollution caused by useless prefetching loses real-time tasks＇ WCET estimates. And a loose on WCET analysis degrades the schedulability of the system and in turn brings down its efficiency. A basic-block based instruction prefetching method is proposed in this paper. The method performs instruction prefetching at the basic block level, avoids useless prefetching, simplifies the instruction hit/miss classifications in the worst-case execution, and reduces the WCET estimates of real-time tasks. Real-time benchmark tests show that, the method can reduce real-time tasks＇ WCET estimates by 20% and also improve instruction cache access performance by 10% on average.

关 键 词：实时系统 最坏情况执行时间 高速缓存性能 指令预取 基本块 

分 类 号：TP316[自动化与计算机技术—计算机软件与理论]