Near memory key/value lookup acceleration

In the "Big Data" era, fast lookup of keys in a key/value store is a ubiquitous operation. We have designed a near memory accelerator combining simple hardware building blocks to accelerate lookup in a hash table based key/value store. We report on the co-design of hardware and software to accomplish fast lookup using open addressing. The accelerator implements a batch get command to look up a set of keys in a single request. Using an FPGA emulator, we evaluate the performance of a query workload under a comprehensive range of conditions such as hash table load factor (fill) and query key repeat distribution (likelihood of a key to reappear in a query workload). We emulate two memory configurations: Hybrid Memory Cube (or High Bandwidth Memory), and Storage Class Memory. Our design shows 12.8X - 2.9X speedup compared to conventional CPU lookup depending on workload characteristics.