基于传输时间精确预测的片上总线仲裁算法  

A Transfer-Time Accurate Prediction Based Arbitration Algorithm for On-Chip Buses

作　　者：孟海波[1] 张志敏[1] 

机构地区：[1]中国科学院计算技术研究所微处理器技术研究中心

出　　处：《计算机辅助设计与图形学学报》2008年第7期830-837,共8页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家“八六三”高技术研究发展计划/CIMS主题基金(2002AA1Z1040);北京市工业促进局项目(京财经一指[2005]1858号)

摘　　要：片上系统中各主设备有不同的实时性和带宽要求,它们竞争使用片上系统总线.总线仲裁器采用各种仲裁算法试图满足实时性和带宽要求,但已有算法很难同时满足这两方面的要求.提出一种基于传输时间精确预测的仲裁算法,采用该算法的仲裁器能够精确地预测在当前仲裁机制下各个请求的完成时间,因此能判断哪些主设备的实时性可能会被违反,从而提前改变总线仲裁策略以满足各主设备实时性要求.同时,采用该算法后仲裁器并行比较主设备的实际传输带宽和需求带宽的差别,及时调整优先权以实现对带宽的精确分配.实验结果表明,该算法比常见的5种算法在实时性要求满足百分比方面平均提高66.47%,很好地满足了各主设备在各种情况下的强实时要求.In system-on-a-chip, different IP （intellectual property） cores have different real-time and bandwidth requirements. Arbiters are adopted to solve bus contentions with various kinds of arbitration algorithms. It is difficult to design an arbitration algorithm to meet both requirements. In this paper, we present a transfer time accurate prediction based arbitration algorithm （TAP）, which can precisely predict the finish time for each transfer. With this algorithm, the arbiter knows which master＇s real-time requirement would be violated and changes the arbitration scheme in time to avoid a potential real time violation. At the same time, the arbiter compares each master＇s real transferred bandwidth with its configured bandwidth and gets useful information for arbitration to provide precise bandwidth allocation. The experimental results show that TAP outperforms five well-known existing arbitration algorithms on real time requirement with the average improvement of 66.47%.

关 键 词：片上系统 片上总线 仲裁算法 强实时性 

分 类 号：TP319.7[自动化与计算机技术—计算机软件与理论]