陳俊良臺灣大學：資訊工程學研究所曾清旭Tseng, Ching-ShiuChing-ShiuTseng2007-11-262018-07-052007-11-262018-07-052005http://ntur.lib.ntu.edu.tw//handle/246246/54019記憶體系統一直是嵌入式行動裝置中，悠關系統效能、能耗及系統成本的重要單位。隨著記憶體裝置技術的發展，兼具非揮發性、資料保存性高、低能耗優點的 Flash Memory 已經成為嵌入式行動裝置記憶體系統中不可或缺的重要元件。 NAND Flash 具有高密度、低成本的特性，隨著新技術的發展，將逐漸取代 NOR Flash 在嵌入式記憶體系統中所扮演 Code Storage 的角色。新的 NAND + RAM 架構下，系統程式及資料將儲存在 NAND Flash 中，而 RAM 則為工作時期資料暫存區。 Java 具有可攜性高的優點, 在嵌入式小型系統實作 Java 平台的需求是日趨重要的課題。Java 虛擬機器的效能，一直為使用者所垢病，更何況是資源有限之嵌入式系統，如何提升 Java 在嵌入式系統的效能一直是個重要的課題。本論文即基於 NAND + RAM 的嵌入式系統記憶體架構下，針對 NAND Flash 分頁循序讀取速度較慢的特性，提出我們 KVM 直譯器的三種改善法則。目標在於降低由 RAM 到 NAND 的分頁失誤率，使得 J2ME 程式在運作中，由 NAND Flash 所帶來的時間延遲及系統能耗降低。Memory system is a main concern to embedded system engineers since it dominates the cost, power and performance of mobile embedded systems. In particular, emerging memory technology, the flash memory is becoming an indispensable component in mobile embedded systems due to its versatile features: non-volatility, solid-state reliability, low power consumption. NAND flash has the nature of high density and low cost. With the shadowing technique support, NAND flash will replace NOR flash for the embedded memory system code storage in nearly future. The more advanced solution is NAND+RAM. Neither NOR flash memory nor mask ROM is used in this architecture; it uses NAND flash memory for code storage. Copying the whole software executable binary code into RAM offers the best performance possible at run time. With the advantage of portability, it is more important to implement Java system for embedded devices. The performance is a major drawback of Java system, especially for resource-limited embedded devices. Therefore, if becomes an interesting topic to improve the Java performance for embedded devices. In our thesis, we present three KVM interpreter optimization schemes based on the NAND+RAM memory architecture and the drawback of NAND page sequential access latency. By reducing of page fault ratio from NAND to RAM, the J2ME execution performance and the NAND flash energy consumption will both be decreased.摘要 i Abstract iii 致謝 v Table of Contents vii List of Figure xi List of Table xiii Chapter 1 Introduction 1 1.1 Motivation 2 1.2 Related Work 3 1.3 Thesis Organization 4 Chapter 2 Connected Limited Device Configuration 5 2.1 CLDC Specification 5 2.1.1 Requirements and Goals 5 2.1.2 Main Difference between CLDC and J2SE 8 2.1.3 CLDC Specification Versions 1.1 vs. 1.0 9 2.2 KVM 10 2.2.1 Introduction to KVM 10 2.2.2 Porting KVM 11 2.2.3 KVM Interpreter 13 Chapter 3 ARM7TDMI Processor and NAND Type Flash Memory 15 3.1 ARM7TDMI 15 3.1.1 Introduce to ARM7TDMI 16 3.1.2 ARM7TDMI Memory Access 17 3.2 NAND Type Flash ROM 18 3.2.1 Flash Memory Architecture 18 3.2.2 NOR vs. NAND 20 3.2.3 NAND Flash Memory 22 3.2.4 Memory Architecture 23 Chapter 4 System Design 25 4.1 KVM Modeling 25 4.2 Measurement Methodology 27 4.3 KVM Interpreter Analysis 30 4.3.1 KVM Interpreter Functional Block Analysis 30 4.3.2 Java Instructions Analysis 31 4.4 Optimization 34 4.4.1 Bytecode Hot/Cold Zone Division 34 4.4.2 Instruction Service Routine Code Placement 36 4.4.3 KVM Interpreter Code Placement 37 Chapter 5 Implementation 41 5.1 CLDC Environment Setup 41 5.2 Simulator Environment Setup 42 5.3 Building Process 43 5.3.1 Cygwin 43 5.3.2 Cross Tool-Chain 44 5.3.3 Emulator and Related Tools 45 5.3.4 uClinux 46 5.3.5 KVM 48 5.3.6 Modification 49 Chapter 6 Performance and Comparison 51 6.1 Benchmark 51 6.2 Environment Parameters 52 6.2.1 Comparison of Algorithms 53 6.2.2 Comparison of Size 54 6.3 KVM2 55 6.3.1 Result 56 6.3.2 Analysis 57 6.4 KVM3 57 6.4.1 Result 59 6.4.2 Analysis 60 Chapter 7 Conclusion and Future Work 63 7.1 Conclusion 63 7.2 Future Work 64 References 65 Appendix A Files in KVM/VmCommon 69 Appendix B Algorithm Configuration 71 Appendix C Hardware Configuration 75 Appendix D KVM2 Results 77 Appendix E KVM3 Results 831152130 bytesapplication/pdfen-USJava虛擬機器省電快閃記憶體嵌入式系統JavaNAND FlashKVMJ2MEFlash MemoryLower PowerVirtual MachineuClinuxARMulator[SDGs]SDG7thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/54019/1/ntu-94-R92922104-1.pdf