SHF: Small: AfterBurner: Efficient Performance Scaling via Post-Retirement Processing

AfterBurner项目着眼于以一种节能的方式在简单和高性能无序核心上提高单线程性能。除了显式并行性之外，这是多核架构向前发展的主要挑战。提高单线程性能的最节能的方法是加速低性能的程序区域。这种方法产生了最大的好处。它还具有低成本，因为它不需要高带宽执行，使其适用于简单和高性能内核。低单线程性能是由于控制和数据错误猜测造成的压缩，以及长延迟负载和存储阻塞管道造成的。AfterBurner结合了最近提出的两种技术——可以有效缓冲大量已完成指令的推测性退役技术和可以重新执行动态生成的程序子图以回补程序状态的选择性重新执行技术——并使用它们来容忍所有四类低性能事件。AfterBurner的多用途基础设施性能方法降低了成本，简化了设计，并扩展了同时遭受不同低性能事件的代码的适用性。除了教育和学生培训之外，AfterBurner项目标志着宾夕法尼亚大学和德雷克塞尔大学计算机科学系之间系统研究合作的开始。

The AfterBurner project looks at improving single-thread performance on both simple and high-performance out-of-order cores in an energy efficient way. Aside from explicit parallelism, this is the primary challenge of multi-core architectures going forward. The most energy-efficient way to improve single-thread performance is to accelerate low-performing program regions. This approach yields the greatest benefit. It also has a low cost because it doesnot require high-bandwidth execution, making it applicable to both simple and high-performance cores. Low single-thread performance is caused by squashes due to control and data mis-speculations and by long latency loads and stores which clog the pipeline. AfterBurner unifies two recently proposed techniques---speculative retirement which can efficiently buffer large numbers of completed instructions and selective re-execution which can re-execute dynamically generated program subgraphs to back-patch program state---and uses them to tolerate all four classes of low-performance events. AfterBurner's multi-purpose infrastructure approach to performance reduces cost, simplifies design, and expands applicability to code that suffers from different low-performance events simulatenously.In addition to education and student tarining, the AfterBurner project marks the beginning of a systems research collaboration between Uniersity of Pennsylvania and Drexel computer science departments.