XPS: EXPL: CCA: A Framework for Portable Parallel Performance

由于无法以历史速度提高计算机处理器的性能增长，微处理器行业已转向在每台计算机中捆绑更多的处理器核心。虽然额外的处理器核心为每台计算机提供了更多的处理能力，但利用这种能力的负担转移到了程序员身上。更糟糕的是，每台计算机中的核心并不完全相同，每个计算机型号可能具有不同的核心数量和混合。为一台计算机优化的软件在另一台计算机上可能表现不佳，让程序员为每种计算机型号进行优化是不切实际的。这个项目旨在通过改变程序员为这些系统编写代码的方式来克服这些问题，并让计算机针对其特定的配置优化软件。该项目将研究如何传达更丰富的信息集，以帮助计算机最好地优化在其上运行的软件。这个项目有可能从根本上改变程序员为现代体系结构开发软件的方式，使他们从针对不同系统优化代码的艰巨任务中解脱出来。任何软件的用户--从计算科学家到家庭桌面用户--都将体验到新应用程序的性能提高和更快的部署。建议的软件界面必须以一种可自动分析的方式表示代码，并高度服从运行时的自动代码转换。该项目将探索许多设计，包括以单静态赋值(SSA)形式显式编码寄存器依赖关系，静态确定内存依赖关系并将其编码为指令，以及使用富有表现力的代码布局方案来提高运行时分析和优化的效率。与这种设计空间探索相一致，将开发各种运行时优化，这些优化将定制特定计算机的软件执行，同时还针对动态变化的用户需求(例如执行速度和能量消耗)进行优化。软件界面和运行时优化的协同设计将允许确定要包括在界面中的最佳信息集。这个项目还旨在为开发人员(编译器、汇编器和体系结构模拟器)创建工具，使其他人能够使用和评估它。PI将继续在他过去在促进多样性和教育推广工作方面取得的成功的基础上继续发展。他每年都会招待几名本科生研究人员，让他们与研究生导师合作。他还将继续将当前的研究成果纳入本科生和研究生课程。

Unable to increase computer processor peformance growth at the historic rate, the microprocessor industry has shifted to bundling more processor cores in each computer. While additional processor cores puts more processing power in each computer, the burden of making use of this power shifts to the programmer. To make matters worse, the cores in each computer are not all the same and each computer model may have a different number and mix of cores. Software optimized for one computer may perform poorly for another, and having programmers optimize for each computer model is not practical. This project intends to overcome these problems by changing the way programmers write code for these systems and having the computer optimize the software for its specific configuration. The project will study ways to convey the richer set of information necessary to help computers best optimize the software running upon it. This project has the potential to fundamentally alter how programmers develop software for modern architectures, relieving them of the arduous task of optimizing their code for different systems. Users of any software---from computational scientists to home desktop users---would experience an increase in performance and faster deployment of new applications.The proposed software interface must represent code in a way that is automatically analyzable and highly amenable to automatic code transformations at runtime. The project will explore many designs, including explicitly encoding register dependences in Single Static Assignment (SSA) form, statically determining and encoding memory dependency information into instructions, and using an expressive code layout scheme to make runtime analysis and optimization more efficient. In concert with this design space exploration, various runtime optimizations will be developed which will customize the software execution for the specific computer while also optimizing for dynamically changing user desires such as execution speed and energy consumption. The synergistic design of the software interface and runtime optimizations will allow determination of the optimal set of information to include in the interface. This project also aims to create tools for developers (compiler, assembler, and architectural simulator) to enable others to use and evaluate it.The PI will keep building on his past successes in fostering diversity and educational outreach efforts. He will host several undergraduate student researchers each year, teaming them with graduate student mentors. He will also continue to incorporate current research results into undergraduate and graduate courses.