DUDETM: Building Durable Transactions with Decoupling for Persistent Memory

作者:Liu Mengxing*; Zhang Mingxing; Chen Kang; Qian Xuehai; Wu Yongwei; Zheng Weimin; Ren Jinglei
来源:ACM Sigplan Notices, 2017, 52(4): 329-343.
DOI:10.1145/3037697.3037714

摘要

Emerging non-volatile memory (NVM) offers non-volatility, byte-addressability and fast access at the same time. To make the best use of these properties, it has been shown by empirical evidence that programs should access NVM directly through CPU load and store instructions, so that the overhead of a traditional file system or database can be avoided. Thus, durable transactions become a common choice of applications for accessing persistent memory data in a crash consistent manner. However, existing durable transaction systems employ either undo logging, which requires a fence for every memory write, or redo logging, which requires intercepting all memory reads within transactions. This paper presents DUDETM, a crash-consistent durable transaction system that avoids the drawbacks of both undo logging and redo logging. DUDETM uses shadow DRAM to decouple the execution of a durable transaction into three fully asynchronous steps. The advantage is that only minimal fences and no memory read instrumentation are required. This design also enables an out-of-the-box transactional memory (TM) to be used as an independent component in our system. The evaluation results show that DUDETM adds durability to a TM system with only 7.4%similar to 24.6% throughput degradation. Compared to the existing durable transaction systems, DUDETM provides 1.7x to 4.4x higher throughput. Moreover, DUDETM can be implemented with existing hardware TMs with minor hardware modifications, leading to a further 1.7x speedup.