CSR---PDOS: Log-Based Architectures: Extending Chip Multiprocessors to Help Software Behave Correctly

由于错误、安全攻击和间歇性硬件错误，软件的行为过于频繁。而强大的工具呢？叫什么?救生员? ?这些工具在过去被开发出来是为了监视程序的执行，以便检测甚至在问题发生时修复问题，但这些工具一直运行得很慢（通常是一个数量级的慢），因此在现场连续运行它们是不切实际的。为了解决这个问题，该项目正在开发一种新的通用框架，该框架利用芯片多处理器中的空闲处理器内核，使功能强大的救生员能够在部署的代码上持续运行，以检测、诊断和修复错误的行为，而不会给用户带来任何成本。在这个新的救生员框架的关键技术是一个新的机制，有效的动态程序检查和倒带通过日志被硬件捕获，由操作系统管理，并暴露给救生员软件。预计该项目将在以下方面产生影响。首先，它应该使软件更加健壮，不仅允许现有的救生员在现场连续运行，而且还有望催生出比我们今天拥有的更复杂、更有用的新救生员。这些工具对于程序员尤其重要，因为他们在为芯片多处理器编写并行程序时试图避免正确性和性能错误。这项新服务将为并行机器提供一种新型的终端用户价值，而不仅仅是单纯的加速（即提高对软件错误、安全攻击和其他错误的鲁棒性）。硬件生成的日志的存在也可能导致编写软件的新方法（例如，通过检查其过去的行为或利用日志作为恢复机制）。

Software misbehaves too frequently due to bugs, security attacks, and intermittent hardware errors. While powerful tools?called ?lifeguards??have been developed in the past to monitor a program as it executes for the sake of detecting and sometimes even fixing problems as they happen, these tools have historically run so slowly (often an order of magnitude slowdown) that it was impractical to run them continuously in the field. To address this problem, this project is developing a new general-purpose framework that harnesses idle processor cores in a chip multiprocessor to enable powerful lifeguards to run continuously on deployed code in order to detect, diagnose, and fix incorrect behaviors with no perceived cost to the user. A key technology in this new lifeguard framework is a novel mechanism for efficient dynamic program inspection and rewind via a log that is captured by the hardware, managed by the operating system, and exposed to the lifeguard software. This project is expected to have impact in the following ways. First and foremost, it should make software more robust, not only by allowing existing lifeguards to be run continuously in the field, but also by hopefully spawning the creation of new lifeguards that are even more sophisticated and useful than what we have today. These tools will be especially important for programmers as they try to avoid correctness and performance bugs when they write parallel programs for chip multiprocessors. This new service will provide a new type of end-user value from a parallel machine beyond raw speedup (i.e. improved robustness against software bugs, security attacks, and other errors). The existence of a hardware-generated log may also lead to new ways to write software (e.g., by inspecting its past behavior or exploiting the log as a recovery mechanism).