A New Embedded Key-Value Store for NVM Device Simulator

The non-volatile memory (NVM) device is a useful way to solve the memory wall in computers. However, the current I/O software stack in operating systems becomes a performance bottleneck for applications based on NVM devices, especially for key-value stores. We analyzed the characteristics of key-value stores and NVM devices and designed a new embedded key-value store for an NVM device simulator named PMEKV. The embedded processor in NVM devices was used to manage key-value pairs to reduce the data transfer between NVM devices and key-value applications. Meanwhile, it also cut down the data copy between the user space and the kernel space in the operating system to alleviate the I/O software stacks on the efficiency of key-value stores. The architecture, data layout, management strategy, new interface and log strategy of PMEKV are given. Finally, a prototype of PMEKV was implemented based on PMEM. We used YCSB to test and compare it with Redis, MongDB, and Memcache. Meanwhile, the Redis for PMEM named PMEM-Redis and PMEM-KV were also used to test and compared with PMEKV. The results show that PMEKV had the advantage of throughput and adaptability compared with the current key-value stores.