EAGER: Recomputation-Based Checkpointing for Sparse Matrices

高性能计算（HPC）对于保持美国在科学、技术、工程和数学（STEM）领域的国际竞争优势和领导地位至关重要。高性能计算的进步对国家利益至关重要，因为它为科学发现提供了基础设施，从而改善了国家的健康、繁荣、福利和国防。为了解决大规模的科学问题，HPC依赖于越来越多的节点和组件，这使得长时间运行的计算更有可能在完成之前因故障而中断。确保计算完成的关键技术是检查点。检查点允许保存计算的快照，以便在发生故障时，可以从上一次快照恢复计算状态并继续执行，而不是从头开始重新启动。该项目的研究旨在通过使其显著更快和降低成本来推进最先进的检查点技术。该项目还计划通过向学生提供NVMM上当前检查点机制的机制和低效性，以及新的就地检查点，为培训未来的劳动力做出贡献。该项目旨在增加少数民族和代表性不足群体的参与，并使本科生参与研究。以前的检查点方法依赖于获取系统状态（系统级检查点）或应用程序状态（应用程序级检查点）的快照，并将其保存到辅助非易失性存储中。随着非易失性主存储器（NVMM）的出现，一种新的检查点方法成为可能。传统的检查点方法依赖于将单独的快照存储在单独的辅助存储器中，与之相反，该项目使用了一种新的方法，在这种方法中，检查点可以利用应用程序使用的工作数据结构在NVMM中就地构造。这只允许除了程序已经保存到内存之外的非常少的额外状态，使检查点显著更快，产生更低的成本，从而提供进一步的HPC扩展。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

High-performance computing (HPC) is essential for maintaining the US international competitive edge and leadership in science, technology, engineering, and mathematics (STEM). Advances in HPC are vital to national interests by providing infrastructure for scientific discovery that improves the national health, prosperity, welfare, and defense. To solve large-scale scientific problems, HPC relies on an increasing number of nodes and components, which makes it likelier for long-running computation to be interrupted with failures before completing. A critical technique to ensure computation completion is checkpointing. Checkpointing allows snapshots of the computation to be saved so that when a failure occurs, computation state can be restored from the last snapshot and continues execution, rather than restarting from the beginning. The research in this project seeks to advance the state-of-the-art checkpointing technique by making it significantly faster and lowering its cost. This project also plans to contribute to the training of future workforce by providing students with exposure to the mechanisms and inefficiencies of current checkpointing mechanisms on NVMM, and the new in-place checkpointing. The project seeks to increase participation of minority and under-represented groups and involves undergraduates in research.Prior approaches to checkpointing rely on taking a snapshot of the system state (system-level checkpointing) or the application state (application-level checkpointing) and saving it to secondary non-volatile storage. With the advent of non-volatile main memory (NVMM), a new approach to checkpointing becomes possible. In contrast to traditional approaches to checkpointing that rely on storing separate snapshots in a separate secondary storage, the project uses a new approach where checkpoints can be constructed in-place in the NVMM utilizing the working data structures used by the applications. This allows only very minimal additional state beyond what the program already saves to memory, making checkpointing significantly faster and incurring lower cost, in turn providing further HPC scaling.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.