SHF: Small: Detecting and Mitigating Smartphone Energy Bugs using Compiler and Runtime Analysis

智能手机正在成为全世界主要的计算设备。 由于其相对于笔记本电脑和台式机的成本较低，它们已成为将计算带给发达国家和不发达国家弱势群体的重要设备。 智能手机与传统计算设备的不同之处在于，它们的主要电源是电池，并且它们预计在一次充电后可以运行一天或更长时间。 这迫使放弃传统的自动功率管理技术，而采用功率和功耗硬件的手动编程器管理，即，“权力阻碍编程。这反过来又导致了“能源缺陷”，导致应用程序失败并缩短电池寿命。 这项工作将开发工具，自动检测由电源占用编程导致的能源缺陷，提高可靠性和电池寿命，并为数亿用户带来更好的用户体验。为了延长电池寿命，智能手机操作系统不断尝试关闭手机。 应用程序包含时间关键部分，即，程序区域，手机必须保持正常工作。 耗电编程要求程序员在时间关键的部分使用唤醒锁定来保持手机硬件的开启（以确保应用程序正常运行），但不再使用唤醒锁定（以最大限度地减少电池消耗）。 一个正确的应用程序有一个完美的对应区域唤醒锁保持手机清醒和时间关键部分。 拟议的研究重点是运行时和编译时技术，以自动识别受唤醒锁保护的时间关键部分和区域，并使用这些信息自动识别和防止应用程序中的能量错误。 由于智能手机应用程序是事件驱动程序，因此将开发分析事件驱动代码的技术，这些技术应广泛适用于一般事件驱动程序的编译时分析。 这项工作的成功完成将导致自动技术，用于检测改善能源缺陷，这反过来将最大限度地提高可用电池寿命，提高智能手机的可靠性，并导致事件驱动程序的编译器分析的重大进展。

Smartphones are becoming the predominant computing device throughout the world. Because of their lower cost relative to laptops and desktops, they have become an important device for bringing computing to disadvantaged people in both the developed and undeveloped worlds. Smartphones differ from traditional computing devices in that their primary power source is a battery, and they are expected to operate for a day or more on a single charge. This has forced the abandonment of traditional, automatic power management techniques and adoption of manual programmer management of power and power-consuming hardware, i.e., "power-encumbered programming." This in turn has led to "energy bugs," which cause apps to fail and to reduce battery life. The proposed work will develop tools to automatically detect energy bugs resulting from power-encumbered programming, increasing reliability and battery life, and bringing a better user experience to hundreds of millions of users.To increase battery life, a smartphone OS constantly attempts to turn off a phone. Apps contain time-critical sections, i.e., program regions where the phone must stay on to function correctly. Power-encumbered programming requires the programmer use wakelocks to keep the phone hardware on during a time-critical section (to ensure an app functions correctly), but no longer (to minimize battery drain.) A correct app has a perfect correspondence between regions where wakelocks keep the phone awake and time-critical sections. The proposed research focuses on runtime and compile-time techniques to automatically identify time-critical sections and regions protected by wakelocks, and to use that information to automatically identify and prevent energy bugs in apps. Because smartphone apps are event-driven programs, techniques to analyze event-driven code will be developed, and these techniques should be broadly applicable to the compile-time analysis of general event-driven programs. Successful completion of this work will lead to automatic techniques for detecting an ameliorating energy bugs, which in turn will maximize the available battery life, increase the reliability of smartphones, and lead to significant advances in the compiler analysis of event-driven programs.