应用于低功耗SoC的动态时钟管理技术

文章着重分析了基于系统级的低功耗技术,提出了动态时钟管理技术,介绍了其背景、原理以及在系统低功耗中发挥的重要作用。最后,将该技术应用到一款LCD控制器中。事实表明,动态时钟管理技术在保证系统性能的前提下,大大降低了功耗,取得了很好的效果。     

Methodology for Refinement and Optimisation of Dynamic Memory Management for Embedded Systems in Multimedia Applications

In multimedia applications, run-time memory management support has to allow real-time memory de/allocation, retrieving and processing of data. Thus, its implementation must be designed to combine high speed, low power, large data storage capacity and a high memory bandwidth. In this paper, we assess the performance of our new system-level exploration methodology to optimise the memory management of typical multimedia applications in an extensively used 3D reconstruction image system [1, 2]. This methodology is based on an analysis of the number of memory accesses, normalised memory footprint¹ and energy estimations for the system studied. This results in an improvement of normalised memory footprint up to 44.2% and the estimated energy dissipation up to 22.6% over conventional static memory implementations in an optimised version of the driver application. Finally, our final version is able to scale perfectly the memory consumed in the system for a wide range of input parameters whereas the statically optimised version is unable to do this.The original version of this paper first appeared in the Proceedings of Signal Processing Systems 2003.Marc Leeman has as professional research interests hardware/software co-design, code optimisation in general and optimisation of dynamic data types and dynamic memory management for low power embedded systems in particular. Personal interests include Open and Free software development, software configuration and GNU/Debian package maintenance. He received an engineering degree, a master in artificial intelligence and a Ph.D. in electrical engineering in 1997, 1998 and 2004 respectively, all at the K.U. Leuven. He is a member of the IEEE Computer Society. Currently, he works as an R&D Engineer for Barco Control-rooms Division (BCD) on hardware/software co-design for streaming video products.David Atienza received the M.Sc. degree in Computer Sciences from the Complutense University of Madrid (UCM), Spain in 2001. Since then he has joined the Department of Computer Architecture and Automation of Complutense University of Madrid as a sandwich Ph.D. student half-time at the Inter-university Micro-Electronics Centre (IMEC), Heverlee, Belgium. His research interests include optimisation of dynamic memory management on multimedia and wireless network applications for low power and high performance embedded systems, computer architecture and high-level design automation.Geert Deconinck is Associate Professor (hoofddocent) at the K.U. Leuven (Belgium) since 2003 and staff member of the research group ELECTA (Electrical Energy and Computing Architectures). His research interests include the design and assessment of software-based solutions to meet dependability, real-time, and cost constraints for embedded systems. In this field, he has authored and co-authored more than 120 publications in international journals and conference proceedings. He received his M.Sc. in Electrical Engineering and his Ph.D. in Applied Sciences from the K.U. Leuven, Belgium in 1991 and 1996 respectively. He was a visiting professor (bijzonder gastdocent) at the K.U. Leuven in 1999–2003. - Flanders (Belgium) in the period 1997–2003.Vincenzo De Florio received his MSc degree in computer science in 1987 and his PhD degree in engineering in 2000, respectively from the University of Bari, Italy, and the University of Leuven, Belgium. He is currently post-doctoral researcher at the University of Antwerp, where he is doing research on adaptive and dependable mobile applications. Previously he had been researcher and lecturer with Tecnopolis/SASIAM (ECMI School for Advanced Studies in Industrial and Applied Mathematics) and member of Tecnopolis/Robotic lab, where he was responsible for design of parallel robotic vision applications. Currently he is also a reviewer for several conferences and for the Journal of System Architectures.José M. Mendías received the M.Sc. and Ph.D. degrees in physics from the Complutense University of Madrid in 1992 and 1998, respectively. He joined the Department of Computer Architecture and Systems Engineering, Complutense University in 1992 as a lecturer, and became an associate professor in 2001. Since 2002, he is Vice-dean of the Computer Science Faculty at the same University. His current research interests include design automation, computer architecture and formal methods.Chantal Ykman-Couvreur is born in 1956. She received the mathematics degree from the Facultes Universitaires Notre-Dame de la Paix of Namur in 1979. She first worked at PHILIPS Research Laboratory of Belgium, from 1979 until 1991. Her main activities were concentrated on information theory and coding, cryptography and multi-level logic synthesis for VLSI circuits. Then, she joined IMEC, where she was responsible at IMEC for the dynamic memory management and the system-level design flow in the Matisse compiler for network protocol components (ATM, Internet Protocol, etc). Currently, she works on the task concurrency management design flow in the Matador project.Francky Catthoor received the engineering degree and a Ph.D. in electrical engineering from the Katholieke Universiteit Leuven, Belgium in 1982 and 1987 respectively. Since 1987, he has headed several research domains in the area of high-level and system synthesis techniques and architectural methodologies, all within the Design Technology for Integrated Information and Telecom Systems (DESICS—formerly VSDM) division at the Inter-university Micro-Electronics Centre (IMEC), Heverlee, Belgium. Currently he is an IMEC fellow. He is part-time full professor at the EE department of the K.U. Leuven.In 1986 he received the Young Scientist Award from the Marconi International Fellowship Council. He has been associate editor for several IEEE and ACM journals, like Transactions on VLSI Signal Processing, Transactions on Multi-media, and ACM TODAES. He was the program chair of several conferences including ISSS97 and SIPS01.Rudy Lauwereins is vice-president of IMEC, Belgiums Interuniversity Micro-Electronic Centre, which performs research and development, ahead of industrial needs by 3 to 10 years, in microelectronics, nano-technology, enabling design methods and technologies for ICT systems. He leads the DESICS division of 185 researchers, currently focused on the development of re-configurable architectures, design methods and tools for wireless and multimedia applications. He is also a part-time Professor at the Katholieke Universiteit Leuven, Belgium. He had obtained a Ph.D. in Electrical Engineering in 1989. Rudy Lauwereins served in numerous international program committees and organisational committees, and gave many invited and keynote speeches. He is vice-chair of the board of DSP Valley and member of the board of several spin-off companies. He is a senior member of the IEEE.     

存储器管理部件的设计实现

主要介绍了一款32b的RISC结构CPU的存储器管理部件的设计。在对存储器管理部件的原理，存在的必要性等方面进行介绍的基础上，对设计的存储器管理部件的结构，3种地址转换机制：实地址转换、块地址转换及段页式地址转换，以及部分单元电路等方面进行了详细的介绍。     

存储器管理单元设计

文章主要介绍了一款RISC结构CPU的存锗器管理单元的设计。对存储器管理单元的地址转换机制设计进行了详细的介绍。     

重点强化联想记忆人工神经网络模型研究

本文研究了一种新的重点强化联想记忆人工神经网络模型,大量计算机模拟结果表明,该模型的特性优于Hopfield网络,当强化系数P较大时,也优于Y.C.Lee高阶关联网络,而其硬件实现较后者容易得多。     

Prototyping Multiprocessor System-on-Chip Applications: A Platform-Based Approach

Multiprocessor system-on-chip designers face challenges during prototyping, when there is a real need for methods and tools that can easily map applications onto different architectures without tedious redesigning. Such methods and tools must also ensure rapid validation. A new MPSoC prototyping and validation approach uses the Posix 1003 1.C API standard and a reconfigurable multiprocessor hardware platform for fast prototyping of Posix-based applications.     

SoC设计中的低功耗逻辑综合策略

介绍了一种SoC(片上系统)电路的高效逻辑综合方法,用工具对功耗关键模块插入时钟门控单元来降低功耗,并用工具提取不带时钟门控模块的约束条件来优化相应带门控的模块,使SoC在最高主频率、面积和功耗等方面达到最优,且时序收敛较快.采用该方法对Unity805plus SoC芯片进行综合,取得比自顶向下、自底向上等传统综合方法更好的效果,在最差情况下最高频率为200 MHz,面积为8 773 410μm2,功耗为724.920 4 mW.在ULTRA60上运行时间为14h.[关键词:逻辑综合,SoC,时序收敛     

VMFS:一种持久性内存统一管理系统

针对当前持久性内存(PM,Persistent Memory)资源管理方案无法兼顾持久化特性和可字节寻址特性的问题,提出了一种融合Linux系统内核虚拟内存系统和文件系统的持久性内存统一管理系统VMFS(Virtual Memory File System).VMFS中的单个PM分区可同时提供内存分配和文件存储服务,并...     

NoC_MPSim:基于片上网络通信架构多核仿真平台

实现了一个用于探索基于片上网络通信架构多核系统设计空间的可配置仿真平台--NoC_MPSim.该平台包含处理器工具链、平台自动化配置脚本以及一个包含处理器、网络适配器以及多种路由器的RTL模型库,可根据用户输入的系统配置信息自动生成周期精确的多核仿真系统.针对片上网络通信架构的特征,定义了基于该通信架构的多核系统的高层次通信抽象模型,并借鉴并行机中的消息传递机制,提出了一种可有效隐藏网络乱序的并行编程模型及其通信原语,并完成其所需要的软\硬件建模.应用提出的编程模型,实现了MUSIC算法基于四核仿真系统的分布式并行计算,并经实验得到该并行MUSIC算法在该系统中加速比可达2.6.     

门控时钟的低功耗设计技术

门控时钟是一种有效的低功耗设计技术，文章介绍了该技术的一种EDA实现方法。介绍了其设计思想和实现细节，重点对设计过程中存在可测性设计(DFT）以及时序分析、优化和验证等问题分别进行了详细分析，并给出了相应的解决方法，以使该技术更好地融入到常用的SoC设计流程当中，发挥更高的效率。     

新型电源管理子系统设计方法缩短产品上市时间

开发周期 当今的技术革新周期要求差不多每18个月就推出新的系统架构,例如新的PDA或笔记本电脑平台。这种状况符合摩尔定律,即给定尺寸裸片上的晶体管数目将每18个月翻一倍(随着时间过去,这个数字的实际增长稍稍减慢,目前基本上是近两年翻一倍)。本文将着重讨论开发新型电源管理子系统的半导体器件时所面对的挑战。     

一种VxWorks内存管理方案

探讨嵌入式开发对内存管理的基本要求、嵌入式开发内存管理的关键问题以及给出一种Vxworks内存管理方案,即把除VxWorks系统保留内存以外的内存分为三种类型进行管理：固定大小的缓冲池、动态可变的堆以及由各种固定大小的缓冲区组成的队列。     

Dynamic Memory Access Management for High-Performance DSP Applications Using High-Level Synthesis

Multimedia applications such as video and image processing are often characterized by a huge number of data accesses. In many digital signal processing applications, array access patterns are regular and periodic. In these cases, optimized architectures using pipelined memory access controllers can be generated. In this paper, we focus on implementing memory interfacing modules that can be automatically generated from a high-level synthesis tool and which can efficiently handle predictable address patterns as well as random ones (i.e., dynamic address computations). The benefits of balancing dynamic address computations from datapath to dedicated computation units in the memory controller is also analyzed as well as operator bitwidth optimization and data locality to save power consumption and reduce latency.      

A Methodology for Transistor-Efficient Supergate Design

The number of transistors required for the implementation of a logic function is a fundamental consideration in digital VLSI design. While the determination of a series-parallel implementation can be straightforward once a simplified Boolean expression of the function is available, this may not be an optimum solution. In this paper, a methodology is developed for minimizing the number of transistors that starts from a sum-of-products expression and utilizes non-series-parallel structures. Experimental results demonstrate the efficiency of the approach     

A four megabit Dynamic Systolic Associative Memory chip

A Dynamic Random Access Memory (DRAM) chip is to be modified to associatively search data in it as it is being refreshed in the chip and to communicate in a linear systolic array. In a preliminary logic design of a (1024×4096) associative memory chip based on a 4 Mbit DRAM, the 6 transistors per sense amplifier in a DRAM are expanded by 9 transistors per sense amplifier in the modified chip. The chip size is only slightly increased, and it is manufactured using the same processes, in the same plant, as a DRAM chip; thus should cost about the same as a DRAM. A large array of such modified DRAMs could store a terabit database and search all of it every 60 microseconds. Bit pattern searching and search-rewrite algorithms could be economically performed over very large amounts of data. The concepts and the design of the simple modified DRAM will be discussed in the paper.     

一种NAND Flash动态坏块管理算法的设计与实现

文章针对NAND Flash在大容量数据存储时对可靠性的要求,提出一种基于逻辑一物理块地址映射表的大容量NAND Flash动态坏块管理算法。该方法可彻底屏蔽对坏块的操作,实现对NAND Flash的有效存储,具有较高的实际应用价值。     

Linux下的存储管理

内存管理单元作为操作系统的核心部分,在整个系统的运行过程中发挥着举足轻重的作用.Linux在其发展过程中不断的在完善和优化内存管理单元的功能和性能.本文总结了Linux2.4内核中存储管理子系统的总体框架,重点介绍存储管理子系统中各个模块的基本特点以及它们之间的联系,深入分析了内存管理的实现技术,对Linux2.4内核中存储管理中的重要的算法、数据结构做了相应的分析描述.     

A Viterbi Decoder with Efficient Memory Management

This paper proposes a new architecture for a Viterbi decoder with an efficient memory management scheme. The trace‐back operation is eliminated in the architecture and the memory storing intermediate decision information can be removed. The elimination of the trace‐back operation also reduces the number of operation cycles needed to determine decision bits. The memory size of the proposed scheme is reduced to 1/(5×constraint length) of that of the register exchange scheme, and the throughput is increased up to twice that of the trace‐back scheme. A Viterbi decoder complying with the IS‐95 reverse link specification is designed to verify the proposed architecture. The decoder has a code rate of 1/3, a constraint length of 9, and a trace‐forward depth of 45.     

一种基于存储器内建自测试的新型动态March算法设计

存储器作为片上系统(SoC)中最大和最重要的模块之一,它的稳定性和可靠性关乎着整个芯片能否正常工作。为了提高存储器的测试效率,该文提出一种新型动态March算法——Dynamic-RAWC。相比经典的March RAW算法,Dynamic-RAWC算法有着更良好的故障检测效果：动态故障覆盖率提高了31.3%。这个可观的效果得益于所提算法以经典的March RAW算法为基础进行优化,融入了Hammer, March C+算法的测试元素和一些新的测试元素。不同于普通March型算法的固定元素,所提算法支持用户自定义算法的执行顺序以适应不同的故障检测需求,能够动态地控制算法元素,在时间复杂度和故障覆盖率之间进行调整从而达到良好的平衡。     

实时嵌入操作系统pSOSTM下外挂式内存管理模块的设计

为在pSOS^TM实时操作系统下设计应用系统软件提供了一种内存管理方法。可以在尽可能不改动代码的情况下对代码中的内存问题的定位提供有效的跟踪手段。