SHF: Small: Using Coding Theory to Optimize the Representation of Information in Computer Architecture

计算机系统处理和存储信息，包括指令、输入和输出。计算机用位（0和1）来表示或“编码”这些信息，这样，给定的位序列就可以描述一个数字、一条指令、一个要打印到监视器上的字符等等。用于编码不同类型信息的位模式的选择会影响计算机的性能、可靠性和能源效率。这个项目是计算机系统架构师和信息编码专家之间的跨学科合作，将开发新的信息表示，提高性能、可靠性和能源效率。该项目将对计算机系统设计和信息编码产生技术影响，并将通过对学生（包括研究生和本科生）的培训以及将少数族裔带到杜克大学进行暑期研究体验的外展计划对社会产生影响。该项目将在四个主要方面取得技术进步。首先，该项目将为存储在写入限制存储介质（如Flash）中的信息开发新的表示形式，目标是延长其使用寿命。本研究的一项关键编码技术是共集编码，系统可以选择将哪个码字写入存储器，并可以选择产生最小损耗的选项。其次，该项目将基于现有的本地可修复代码开发新的代码，用于写入可能遭受永久故障的所有类型的存储。这些代码可以通过最小化必须访问的存储位置来实现有效的本地故障修复。第三，该项目将开发新的指示表示，以提高性能和能源效率。特别是，该项目将为gpu开发新的指令编码，即使在存在分支分歧的情况下也能完成有用的工作。第四，该项目将开发和应用网络编码技术，以提高处理器核心之间通信的性能和可靠性。

Computer systems process and store information, includinginstructions, inputs, and outputs. Computers represent, or "encode",this information with bits -- zeros and ones -- such that a givensequence of bits can describe a number, an instruction, a character toprint to the monitor, etc. The choice of bit patterns used to encodedifferent types of information impacts the performance, reliability,and energy-efficiency of a computer. This project -- which is aninterdisciplinary collaboration between a computer systems architectand an expert in information coding -- will develop new informationrepresentations that improve performance, reliability, andenergy-efficiency. This project will have both technical impact oncomputer system design and information coding, and it will impactsociety through its training of students (both graduate andundergraduate) and an outreach program that brings under-representedminorities to Duke for summer research experiences. This project will make technical advances in four main avenues.First, the project will develop new representations for theinformation that is stored in write-limited storage media like Flash,with the goal of extending its lifetime. A key coding technology inthis research thrust is coset coding, in which the system has multiplechoices for which codeword to write to the storage and can choose theoption that incurs the least wear. Second, the project will developnew codes, based on existing locally repairable codes, for writing toall types of storage that can suffer permanent failures. These codescan enable efficient, local repair of failures by minimizing thenumber of storage locations that must be accessed to perform therepair. Third, the project will develop new representations ofinstructions to improve performance and energy-efficiency. Inparticular, the project will develop new encodings of instructions forGPUs that enable useful work to be done even in the presence of branchdivergence. Fourth, the project will develop and apply network codingtechniques to improve the performance and reliability of communicationbetween processor cores.