CPHASH: A cache-partitioned hash table Citation

CPHASH is a concurrent hash table for multicore processors. CPHASH partitions its table across the caches of cores and uses message passing to transfer lookups/inserts to a partition. CPHASH’s message passing avoids the need for locks, pipelines batches of asynchronous messages, and packs multiple messages into a single cache line transfer. Experiments on a 80-core machine with 2 hardware threads per core show that CPHASH has ∼ 1.6× higher throughput than a hash table implemented using fine-grained locks. An analysis shows that CPHASH wins because it experiences fewer cache misses and its cache misses are less expensive, because of less contention for the on-chip interconnect and DRAM. CPSERVER, a key/value cache server using CPHASH, achieves ∼ 5% higher throughput than a key/value cache server that uses a hash table with fine-grained locks, but both achieve better throughput and scalability than MEMCACHED. Finally, the throughput of CPHASH and CPSERVER scales near-linearly with the number of cores.