HMB-SSD: Framework for Efficient Exploiting of the Host Memory Buffer in the NVMe SSD

Host Memory Buffer (HMB) is a highlighted feature of the Non-Volatile Memory Express (NVMe) protocol, which is the state-of-the-art storage interface for emerging storage devices such as Solid-State Drives (SSDs). HMB enables the underlying storage to make use of a portion of host memory for caching their address mapping information and/or user data, so that they can overcome the limited capacity of memory within the storage. This technology opens an opportunity to optimize the I/O performance cost-effectively by sharing the ample host memory with the severely resource-constrained device. However, it is challenging to study the HMB-based optimization techniques in the practical system because there is no SSD development platform supporting the HMB feature as well as the commercial SSD products veil their internals, not allowing a custom extension. Motivated by this limitation, this paper presents an HMB-supported SSD development platform called HMB-SSD, which is built by faithfully extending an open-source SSD emulator. HMB-SSD enables to easily integrate and evaluate I/O techniques for the HMB feature in an SSD emulator, which closely mimics the behavior of real devices. We demonstrate the proper operation of our platform and the efficacy of the HMB feature with a case study on write buffering. In our empirical study, the SSD storage achieves a large performance benefit with the HMB-based write buffer, yielding up to 86.2% better performance than that of without it.