USENIX Association 10th USENIX Symposium on Networked Systems Design and Implementation (NSDI ’13) 371 MemC3: Compact and Concurrent MemCache with Dumber Caching and Smarter Hashing

This paper presents a set of architecturally and workload-inspired algorithmic and engineering improvements to the popular Memcached system that substantially improve both its memory efficiency and throughput. These techniques—optimistic cuckoo hashing, a com-pact LRU-approximating eviction algorithm based upon CLOCK, and comprehensive implementation of opti-mistic locking—enable the resulting system to use 30% less memory for small key-value pairs, and serve up to 3x as many queries per second over the network. We have implemented these modifications in a system we call MemC3—Memcached with CLOCK and Concur-rent Cuckoo hashing—but believe that they also apply more generally to many of today’s read-intensive, highly concurrent networked storage and caching systems.