ST-CRTS: A Coordinated Performance-Directed Attack on Underperformance

现代高性能系统长期处于利用率不足的状态，不是因为它们的作业队列很短，而是因为每个任务只使用了每个节点上可用功率的一小部分。尽管学术界和研究实验室多年来一直致力于改善这种情况，但编译后的代码并没有达到可用性能的合理比例。一些性能差距是由于架构和设计；然而，它的一部分直接归因于优化编译器的设计。标准的优化技术无法发现和修复这些问题，部分原因是它们在过程级粒度上操作，部分原因是补救方法要求编译器改变其优化该部分代码的方法，以使用另一种顺序或另一种转换方案。在这个项目中，PI将开发一个反馈驱动的自适应编译工具，专门针对性能不佳的小区域进行改进。为了使区域方案发挥作用，他的团队将加强和重新制定两个强大的优化，即重新物质化和重新关联，并重新界定其他优化，使它们在区域范围内而不是在全球范围内运作。该项目将直接支持莱斯大学的研究生教育。积极的研究成果将在莱斯大学有关该主题的研究生课程中讲授；由于该课程的教学材料已在其他机构使用，因此该材料将被广泛使用。该项目的工作将增加莱斯大学研究编译器的代码库，该编译器以源代码形式免费分发给学术界和工业界的其他人。该项目将结合当地基金和定向研究项目，让本科生直接参与这项工作。

BackgroundModern high-performance systems are chronically underutilized not because their job queuesare short, but because each task uses just a small fraction of the power available on each node.Compiled code simply does not achieve a reasonable fraction of the available performance, despiteyears of work in academia and in research labs that aimed to improve the situation. Some of theperformance gap is due to architecture and design; however, a portion of it is directly attributableto the design of optimizing compilers. Standard optimization techniques fail to discover and fix such problems, in part because they operate at a procedure-level granularity and in part because the remedy requires the compiler to change its approach to optimizing that part of the code to use another order or another transformation scheme. Intellectual Merit In this project, the PI will develop a feedback-driven adaptive compilation harnessthat specifically targets improvements in small regions of underperformance. To make the regionalscheme work, his team will enhance and reformulate two powerful optimizations, rematerialization andreassociation, and re-scope others so that they operate on a regional rather than a global scope.Broader ImpactThis project will directly support graduate education at Rice. The positive researchresults will be taught in a Rice graduate course on the subject; the material will reach a broadaudience because the teaching materials for the course are used at other institutions. The work inthis project will add to the code base for the Rice University research compiler, which is distributed free ofcharge in source-code form to others in both academia and industry. The PI will use a combination oflocal funds and directed research projects to include undergraduates directly in this work.