EFLightPM: An Efficient and Lightweight Persistent Memory System

Emerging non-volatile memory (also termed as persistent memory, PM) technologies promise persistence, byte addressability and DRAM-like read/write latency. A proliferation of persistent memory systems such as Mnemosyne, NVHeaps, PMDK and HEAPO have been proposed to leverage PM for fast data persistence. However, their performance may suffer from inefficiency issues, mainly caused by kernel/user layer context switches and heavy transaction logging overhead. Concretely, getting a persistent region in Mnemosyne, NV-Heaps and PMDK needs two kernel/user layer context switches since the mmap-like system calls are used, which leads to high latency. To guarantee data consistency, existing systems employ redo or undo logging techniques but they bring non-negligible overhead due to double writes and persistence ordering. In this paper, we develop EFlightPM, an efficient and lightweight persistent memory system to manage data in a fine-grained style. We decouple the data organization for persistent regions by placing large regions in the kernel layer while exposing small regions in the user layer. We also design a lightweight transaction mechanism using hybrid logging with high efficiency by minimizing the writes in the critical path. The experimental results show that compared with state-of-the-art persistent memory systems, EFlightPM manipulates fine-grained persistent data with less persistent region operation overhead and more transaction throughput.