CSR: Medium: Collaborative Research: Architecture and System Support for Power-Agile Computing

电池续航时间短是当今智能手机用户的最大抱怨之一，并限制了这些移动的设备的变革潜力。硬件组件继续提供新的节能功能，但今天的移动的操作系统还没有准备好利用这些新功能。该项目研究了新的硬件-软件协调机制，以更有效地利用现有和下一代硬件节能功能。重点是通过引入新的操作系统接口和抽象来提高“电源灵活性”，这是一种衡量系统在硬件组件之间自适应地重新分配能量以满足运行应用程序不断变化的需求的能力的方法。与以前试图直接管理能量的方法相比，本项目探索了测量和管理能量效率的想法，其定义为实际用于执行任务的额外能量的量高于任务所需的最小量。分配低效率，而不是能量，解决了以前的能量管理方法的许多问题，同时仍然允许操作系统在任务之间优先考虑能量使用。通过分配低效率，功率敏捷操作系统可以安全地允许任务直接使用用户空间调优库来调优硬件组件，从而允许它们在追求各种不同的能源管理策略的同时，响应不断变化的需求进行跨组件权衡。该项目还通过在两个合作机构开设一门关于功率敏捷计算的新课程，将教育与研究相结合。

Short battery lifetimes are one of the top complaints of today's smartphone users and are limiting the transformative potential of these mobile devices. Hardware components continue to offer new energy-saving features, but today's mobile operating systems are ill-prepared to utilize these new capabilities. This project investigates novel hardware-software coordination mechanisms to make use of existing and next-generation hardware energy-saving features more effectively. The focus is improving "power agility", a measure of a system's ability to adaptively reallocate energy between hardware components to meet the changing needs of running applications, through the introduction of new operating system interfaces and abstractions.In contrast to previous approaches that attempt to manage energy directly, this project explores the idea of measuring and managing energy inefficiency, defined as the amount of extra energy actually used to perform a task above the minimum required for the task. Allocating inefficiency, rather than energy, addresses many of the problems with previous energy management approaches while still allowing the operating system to prioritize energy usage between tasks. By allocating inefficiency, power-agile operating systems can safely allow tasks to tune hardware components directly using userspace tuning libraries, allowing them to make cross-component tradeoffs in response to changing requirements while pursuing a wide variety of different energy management strategies. The project also integrates education with the research through a new course on power-agile computing at both of the collaborating institutions.