Analytical performance modelling of lock management in distributed systems

From a project on upgrading an existing commercially used operating system for support of a distributed system architecture, we present results and experience from a comprehensive analytical performance evaluation of a large number of different implementation strategies for distributed lock management. The various lock management policies we consider differ in the management of the lock database, in optimization concepts applied, and in the corresponding communication protocol. The system architectures discussed include a centralized lock management, a lock management with a partitioned lock database both with immediate and direct communication and with a token ring based communication, and a lock management with a replicated lock database and token ring communication. We derive analytical formulae for the dependence of expected response time of lock requests and their throughput, and provide a practical example.