SHF: Small: Collaborative Research: ShapeShifting and PubSub for Tailoring Memory Access and Communication in Heterogeneous Multiprocessors

在过去的十年或更长时间里，微处理器在为当前和新兴的软件应用实现高性能同时遵守严格的功率和热限制方面面临着越来越多的挑战。作为响应，工业已经转向使用专用图形和计算硬件以及复杂存储器组织的方法。 最终的结果是计算机系统变得更加异构和复杂，使得程序员难以编写高效和高性能的软件。 调整为在一个实现上运行的软件通常根本无法运行，或者当移植到同一芯片家族中的不同实现时，性能很差或不可预测。这项研究工作的目的是设计和评估系统和硬件支持，定制的内存和数据访问/运动，以提高性能和电源效率，同时也缓解了可编程性和调整软件的问题，为个别chip characteristics. Two的关键主题这项工作是ShapeShifting和PubSub数据抽象。 ShapeShifting是指允许数据在布局中转换的优化和硬件支持结构，以便支持更快的访问，更有效地使用内存以及提高功率和性能的其他属性。 在一些初步的实验中，即使是ShapeShifting的纯软件实现也可以将性能提高15%-2.8倍。PubSub数据抽象为各个处理器提供了方法，以表明对其他程序变量的更新感兴趣（或不感兴趣）。 这些抽象构成了为应用程序量身定制的内存优化的基础。的内存使用模式。通过减少错误共享，鼓励粗粒度的提取，并减少对不感兴趣的核心的一致性广播，PubSub有可能将多核实现的功率和性能效率提高2倍或更多。该研究计划针对几种类型的广泛影响。 首先，该项目开发的模拟器和工具将作为免费的开源软件发布。其次，研究结果可以提高未来并行硬件的性能和能源效率。 从国家经济和战略的角度来看，能源效率特别令人关注，因为计算机系统的电力消耗不断增长，存储器层次结构在影响计算机电力消耗方面发挥着重要作用。

Over the past decade or more, microprocessors have faced increasing challenges in achieving high-performance for current and emerging software applications while abiding by severe power and thermal limits. In response, industry has turned to approaches that use specialized graphics and computational hardware and complex memory organizations. The end result is that computer systems have become more heterogeneous and complex, in ways that make it difficult for programmers to write efficient and high-performance software. Software tuned to run on one implementation will often not run at all or will perform poorly or unpredictably when ported to even a different implementation in the same chip family. The objective of this research effort is to design and evaluate system and hardware support that tailors memory and data access/movements to improve performance and power efficiency, while also easing the issues of programmability and of tuning software for individual chip characteristics.The two key themes of this work are ShapeShifting and PubSub data abstractions. ShapeShifting refers to optimizations and hardware support structures that allow data to be transformed in layout, in order to support faster access, more efficient use of memory, and other attributes that improve power and performance. In some preliminary experiments, even a software-only implementation of ShapeShifting improves performance by 15%-2.8X. PubSub data abstractions offer methods for individual processors to indicate interest (or disinterest) in updates regarding other program variables. These abstractions form the underpinning for memory optimizations that are tailored to the application?s memory usage patterns. By mitigating false sharing, encouraging coarse-grained fetches, and reducing coherence broadcasts to uninterested cores, PubSub has the potential to improve the power and performance efficiency of multi-core implementations by a factor of 2X or more.The research program is targeting several types of broad impact. First, the simulators and tools developed by this project will be released as free, open-source software. Second, the results can enhance performance and energy efficiency of future parallel hardware. Energy-efficiency is of particular concern from a national economic and strategic standpoint, given the growing electricity consumption of computer systems and the important role of the memory hierarchy in influencing computer power consumption.