CSR-PSCE, SM: Recording and Deterministically Replaying Shared-memory Multiprocessor Execution Efficiently

记录并确定性地重放执行过程，使系统设计人员能够在时间上进行回溯。 计算机系统中的时间旅行意味着在计算机系统上重建任意过去状态和事件的能力。 一般来说，重新创建过去的状态和事件是通过在软件运行时记录关键事件来实现的，然后恢复到先前的检查点并重放记录的日志以强制软件确定性地沿着相同的执行路径。这种诱人的机制在现代系统中有着广泛的应用，包括调试程序，执行事后安全分析，以及提高容错能力。 为了最大限度地提高效率，重放系统应该（i）以生产运行的速度记录，（ii）保持记录需求分钟，（iii）以类似于初始执行的速度重放。 用于确定性重放的纯软件系统实现了单处理器系统的这些目标，但是在多处理器系统上遭受较差的性能。 纯硬件系统在多处理器系统上有效地记录和重放，但是当前针对纯硬件系统的提议在很大程度上是不切实际的，因为它们在硬件内放置了太多的功能，并且因为它们没有在同一系统上同时混合记录、重放和传统执行。 本研究将集中于Capo的设计与实作，Capo是一个混合式的硬体/软体重播系统，能有效地记录与重播多处理器系统上的执行。 本研究的主要贡献将是设计和实现第一个硬件/软件接口，结合硬件和软件级重放系统。 该接口将作为新一代重放系统的基础，该系统将实现软件级重放系统的灵活性和硬件级重放系统的效率。如果成功，该研究将对工业产生重大影响，通过使并行代码的确定性重放的有效使用。该团队将以开源的方式发布所有软件产品，这将有助于许多机构的研究人员和教育工作者。除了他们的研究贡献外，该团队还将增强一系列课程，并在并行系统中扩展他们的课程设置-特别是在本科阶段。PI对本科教育有着长期的承诺，经常让本科生参与他们的研究，并让他们接触并行软件和硬件。PI将继续让本科生和研究生参与他们的研究小组。这个项目对本科生来说很有吸引力，因为它涉及两个不同系统层的交互。

Recording and deterministically replaying execution gives system designers the ability to travel backward in time. Time travel in computer systems means the ability to recreate arbitrary past states and events on the computer system. In general, recreating past states and events is achieved by logging key events when the software runs, then restoring to a previous checkpoint and replaying the recorded log to force the software down the same execution path deterministically. This alluring mechanism has enabled a wide range of applications in modern systems including debugging programs, performing post-hoc security analysis, and improving fault tolerance. To maximize effectiveness, replay systems should (i) record at production-run speeds, (ii) keep logging requirements minute, (iii) replay at a speed similar to that of the initial execution. Software-only systems for deterministic replay achieve these goals for uni-processor systems, but suffer from poor performance on multiprocessor systems. Hardware-only systems record and replay efficiently on multiprocessor systems, but current proposals for hardware-only systems are largely impractical since they place too much functionality within the hardware and because they do not mix recording, replaying, and traditional execution on the same system concurrently. This research will focus on the design and implementation of Capo, a hybrid hardware/software replay system that will record and replay execution on multiprocessor systems efficiently. The key contribution of this research will be designing and implementing the first hardware/software interface for combining hardware and software level replay systems. This interface will serve as the foundation for a new generation of replay systems that will achieve both the flexibility of software-level replay systems and the efficiency of hardware-level replay systems.If successful, this research will have substantial impact on industry, by enabling the effective use of deterministic replay of parallel codes. The team will release all software artifacts as open source, which will help researchers and educators in many institutions.In addition to their research contributions, this team will enhance a series of courses and expand their course offerings in parallel systems - especially at the undergraduate level. The PIs have a long-standing commitment to undergraduate education, routinely involving undergraduates in their research and exposing them to parallel software and hardware. The PIs will continue to involve undergraduate and graduate students in their research groups. This project is compelling to undergraduates because it involves the interaction of two different system layers.