NoC目录协议能耗分析与建模研究  

Analysis and Modeling of Directory Protocol Energy Consumption in NoC

作　　者：王继禾[1] 郭兵[1] 沈艳[2] 伍元胜[1] 刘云本[1,2] 

机构地区：[1]四川大学计算机学院,成都610065 [2]成都信息工程学院控制工程学院,成都610225

出　　处：《计算机学报》2011年第9期1603-1610,共8页Chinese Journal of Computers

基　　金：国家自然科学基金(61073045);国家"八六三"高技术研究发展计划项目基金(2008AA01Z105);四川省杰出青年科技基金(2010JQ0011)资助~~

摘　　要：在MPSoC芯片设计中,能耗问题是一个关键因素,NoC(Network-on-Chip片上网络)的能耗占芯片总能耗的50%以上.文中首先对NoC应用层协议的能耗行为进行统一的数学描述,在此基础上,针对目前Cache一致性中常用的目录协议进行深入分析,提出一种基于位置概率分布的目录协议能耗模型,其考虑目录信息与数据块节点位置分布的无关性,定位数据块在NoC中的节点位置,计算任意节点间数据传输的概率矩阵,并结合路由单元能耗、连线能耗以及网络拓扑结构,准确获得目录协议中一次数据块传输的能耗.仿真实验表明,该文提出的模型在发包概率稳定的Mesh(网孔)网络中可有效计算出不同类型目录协议产生的能耗,且精度较高(误差小于2%),为下一步协议能耗优化研究提供可信的量化的评判依据.Energy consumption has become one of the critical factors in MPSoC design. Especially, NoC （Network-on-Chip） contributes more than 50% of energy dissipation in the whole chip. After a uniform energy consumption behavior in the NoC application protocols is described, this paper analyses the processing detail of directory protocol that is a kind of widely used implementation of cache coherence protocol, and proposes an energy model based on the location probability distribution, which can locate the position of a basic data block （DB） in NoC by considering the irrelevance between the directory information and data location distribution, and calculate a probability matrix that denotes the transferring rate in any two nodes of NoC. While combining with the routing unit energy consumption, line energy consumption and network topology factors, single DB transferring energy consumption in the directory protocol can be accurately obtained. Simulation results show that this model can effectively compute the energy consumption of different kinds of directory protocols with stable transferring rate in Mesh networks, and a higher precision with less than 2 % error is achieved. This model can also provide a credible quantitative criterion for the optimization of directory protocol energy consumption in the next step.

关 键 词：MPSOC NOC 协议功耗 目录协议 CACHE一致性 

分 类 号：TP306[自动化与计算机技术—计算机系统结构]