Tapping the Potential of Spiral Storage for Persistent Memory

Spiral storage is a dynamic hashing scheme proposed several decades ago. It has been largely overlooked in the recent adaptation of disk/DRAM-oriented dynamic hashing schemes to persistent memory (PM). The main reason is that its computational complexity is higher than that of its two well-known peers (extendible hashing and linear hashing). After an in-depth analysis, however, we discover that spiral storage has a good potential for PM as it expands a hash table through address remapping, which leads to fewer PM reads and writes. To tap the potential of spiral storage in PM, we develop a persistent spiral storage called PASS (Persistence-Aware Spiral Storage), which is facilitated by a group of new/existing techniques. Further, we conduct a comprehensive evaluation of PASS on a multi-core server equipped with Intel Optane DC Persistent Memory Modules (DCPMM). The experimental results demonstrate that compared with four state-of-the-art schemes it exhibits comparable or even better performance and scalability. In addition, it achieves a similar load factor and requires the same amount of recovery time.