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

随着多核架构的出现，在单个芯片中集成巨大的计算能力的前景，从而使并行计算在所有类型的平台，包括手持计算机和台式机。为应用程序提供适当的软件支持对于利用这种架构的真正力量至关重要。多核的一个固有特征是运行时变化：可靠性，能量/热行为和过程变化将在多核的相同设计的组件之间变化，对应用功耗和性能产生负面影响。如果不适当地解决，则电阻变化已经被识别为可能阻碍电路的进一步缩放的关键问题之一。这个研究项目正在开发一个先进的执行系统，称为鲁棒执行环境（REEact），动态调解，控制和适应应用程序的执行，以运行时资源的景观源于运行时的变化。它采用了一种技术组合，以适应硬件资源和应用程序软件代码，以克服运行时变化的影响。在硬件级别，它调整资源，例如设置多核上节点的速度/电压。在软件层面，REEact动态优化代码，考虑到运行时变化引起的性能和功耗。它有助于操作系统确定在运行应用程序时使用哪些资源。REEact将其动态发现的有关延迟、功率和应用程序行为的信息通知给操作系统。REEact构建为多层分层运行时系统，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.