Performance Evaluation of the Late Delta Cache Coherence Protocol

This paper presents the results of a simulation study designed to compare the performance of the late delta cache coherence protocol and a conventional directory based invalidation protocol. Delta cache protocols are a highly concurrent directory based family of coherence protocols which exploit an isotach logical time system to provide support for sequential consistency and atomicity. The late delta protocol is an update based member of this family of protocols. Our results demonstrate the efficacy of the late delta protocol across a wide range of workloads. We show that this protocol provides comparable performance to the conventional invalidation protocol under workloads with no atomicity requirements and little contention, but outperforms the conventional invalidation protocol as atomicity requirements and contention increase.