Department of Computer Engineering, Kwangwoon University, Nowon-gu, Seoul, Republic of Korea.
School of Computer and Information Engineering, Kwangwoon University, Nowon-gu, Seoul, Republic of Korea.
PLoS One. 2020 Mar 2;15(3):e0229645. doi: 10.1371/journal.pone.0229645. eCollection 2020.
Solid-state drives (SSDs) that do not have internal dynamic random-access memory (DRAM) are being widely spread for client SSD and embedded SSD markets in recent years because they are cheap and consume less power. Obviously, their performance is lower than conventional SSDs because they cannot exploit advantages of DRAM in the controller. However, this problem can be alleviated by using host memory buffer (HMB) feature of Non-Volatile Memory Express (NVMe), which allows SSDs to utilize the DRAM of host. In this paper, we show that commercial DRAM-less SSDs clearly exhibit worse I/O performance than SSDs with internal DRAM, but this can be improved by using the HMB feature. We also present methods that reveal how the host memory buffer is used in commercial DRAM-less SSDs to improve I/O performance. Through extensive experiments, we conclude that DRAM-less SSDs evaluated in this study mainly exploit the host memory buffer as an address mapping table cache rather than a read cache or write buffer to improve I/O performance.
近年来，由于价格低廉、功耗低，不具备内部动态随机存取存储器 (DRAM) 的固态硬盘 (SSD) 在客户端 SSD 和嵌入式 SSD 市场得到了广泛应用。显然，由于它们无法在控制器中利用 DRAM 的优势，因此其性能低于传统 SSD。但是，非易失性内存 Express (NVMe) 的主机内存缓冲区 (HMB) 功能可以缓解此问题，该功能允许 SSD 利用主机的 DRAM。在本文中，我们表明，商业上无 DRAM 的 SSD 的 I/O 性能明显比具有内部 DRAM 的 SSD 差，但可以通过使用 HMB 功能来改善。我们还提出了一些方法，揭示了商用无 DRAM 的 SSD 如何使用主机内存缓冲区来提高 I/O 性能。通过广泛的实验，我们得出结论，本研究中评估的无 DRAM SSD 主要将主机内存缓冲区用作地址映射表缓存，而不是读缓存或写缓冲区，以提高 I/O 性能。
