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 have been proposed to leverage PM for fast data persistence and expose malloc-like persistent APIs. By eliminating disk I/Os, these systems gain low-latency and high-throughput access performance for persistent data. However, there still exist non-negligible limitations in these systems, such as frequent context switches, inefficient allocation, heavy logging overhead, and lack of wear-leveling techniques. To solve these problems, we develop Lewat, a lightweight, efficient, and wear-aware transactional persistent memory system. Lewat is built in user-layer to avoid kernel/user layer context switches and enables lightweight persistent data access. We decouple the data space into slot zone and page zone. Based on this, we design different allocators in these two zones to achieve efficient allocation performance for both small-sized data and large-sized data. To minimize logging overhead, we propose an efficient adaptive logging framework. The main idea is to utilize different logging techniques for different workloads. We also propose a suite of system-coupled wear-leveling techniques that contain wear-aware allocation, wear-aware update, and write reduction. We evaluate Lewat on a real non-volatile memory platform and the experimental results show that compared with state-of-the-art persistent memory systems, Lewat has much lower latency and higher throughput.

中文翻译：

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Lewat：轻量级、高效且磨损感知的事务性持久内存系统


新兴的非易失性内存（也称为持久内存，PM）技术有望实现持久性、字节寻址能力和类似 DRAM 的读/写延迟。人们提出了持久内存系统的激增，以利用 PM 实现快速数据持久性并公开类似 malloc 的持久 API。通过消除磁盘 I/O，这些系统获得了持久数据的低延迟和高吞吐量访问性能。然而，这些系统仍然存在不可忽视的局限性，例如频繁的上下文切换、低效的分配、大量的日志记录开销以及缺乏磨损均衡技术。为了解决这些问题，我们开发了 Lewat，一个轻量级、高效且磨损感知的事务性持久内存系统。 Lewat 内置于用户层，以避免内核/用户层上下文切换，并支持轻量级持久数据访问。我们将数据空间解耦为槽区和页区。基于此，我们在这两个区域中设计了不同的分配器，以实现小数据和大数据的高效分配性能。为了最大限度地减少日志记录开销，我们提出了一种高效的自适应日志记录框架。主要思想是针对不同的工作负载使用不同的日志记录技术。我们还提出了一套系统耦合的磨损均衡技术，其中包含磨损感知分配、磨损感知更新和写入减少。我们在真实的非易失性内存平台上对 Lewat 进行了评估，实验结果表明，与最先进的持久内存系统相比，Lewat 具有更低的延迟和更高的吞吐量。