CPA-CPL-T: Collaborative Research: REEact: A Robust Execution Environment for Fragile Multicore Systems

随着多核体系结构的出现，将巨大的计算能力集成到单个芯片上的希望随之而来，从而在包括手持计算机和台式计算机在内的所有类型的平台上实现并行计算。为应用程序提供适当的软件支持对于利用此体系结构的真正功能至关重要。多核的一个固有特征是运行时变化，这是一个重大障碍：可靠性、能量/热行为和过程变化将在多核相同设计的组件中发生变化，从而对应用程序功耗和性能产生负面影响。运行时变化已被确定为关键问题之一，如果不适当解决，可能会阻碍电路的进一步扩展。这个研究项目正在开发一种高级的执行系统，称为健壮执行环境（REEact），它可以动态地调节、控制和调整应用程序的执行，以适应运行时资源的变化。它在调整硬件资源和应用软件代码方面采用了多种技术组合，以克服运行时变化的影响。在硬件级别，它调整资源，例如在多核上设置节点的速度/电压。在软件层面，react动态优化代码，考虑到运行时变化导致的性能和功耗。它需要操作系统的帮助来决定在运行应用程序时使用哪些资源。react将动态发现的有关延迟、功率和应用程序行为的信息通知操作系统。react被构建为多层分层运行时系统，它与并行应用程序、操作系统和底层多核架构进行交互，以确保实现最大性能。

With the emergence of the multicore architecture comes the promise of integrating enormous computing power in a single chip, thereby enabling parallel computing in all types of platforms including handheld computers and desktop machines. Providing proper software support for applications is critical to harness the true power of this architecture. An inherent characteristic of multicores that presents a significant obstacle is runtime variation: reliability, energy/thermal behavior and process variation will vary across identically designed components of a multicore, producing a negative impact on application power consumption and performance. Runtime variation has been identified as one of the key problems that could block further scaling of circuits if not properly addressed. This research project is developing an advanced execution system, called a Robust Execution Environment (REEact), that dynamically mediates, controls and adapts an application's execution to the runtime resource landscape originating from runtime variations. It employs a combination of techniques in adapting both the hardware resources and the application software code to overcome the impact of runtime variations. At the hardware level, it adapts the resources, such as setting the speed/voltage of a node on the multicore. At the software level, REEact dynamically optimizes code, taking into account performance and power consumption due to runtime variations. It elicits the help of the OS in determining what resources to use in running the application. REEact informs the OS about information it dynamically discovers about latency, power, and application behavior. REEact is built as multi-layer hierarchical runtime system that interacts with the parallel application, the OS, and the underlying multicore architecture to ensure that maximum performance is achieved.