A Configuration Control Mechanism Based on Concurrency Level for a Reconfigurable Consistency Algorithm

A Reconfigurable Consistency Algorithm (RCA) is an algorithm that guarantees the consistency in Distributed Shared Memory (DSM) Systems. In a RCA, there is a Configuration Control Layer (CCL) that is responsible for selecting the most suitable RCA configuration (behavior) for a specific workload and DSM system. In previous works, we defined an upper bound performance for RCA based on an ideal CCL, which knows apriori the best configuration for each situation. This ideal CCL is based on a set of workloads characteristics that, in most situations, are difficult to extract from the applications (percentage of shared write and read operations and sharing patterns). In this paper we propose, develop and present a heuristical configuration control mechanism for the CCL implementation. This mechanism is based on an easily obtained applications parameter, the concurrency level. Our results show that this configuration control mechanism improves the RCA performance in 15%, on average, compared to other traditional consistency algorithms. Furthermore, the CCL with this mechanism is independent from the workload and DSM system specific characteristics, like sharing patterns and percentage of writes and reads.