Simple analytic modeling of software contention

Being able to model contention for software resources (e.g., a critical section or database lock) is paramount to building performance models that capture all aspects of the delay encountered by a process as it executes. Several methods have been offered for dealing with software contention and with message blocking in client-server systems. We present in this paper a simple, straightforward, easy to understand and implement, approach to modeling software contention using queuing networks. The approach consists of a two-level iterative process. Two queuing networks are considered: one represents software resources and the other hardware resources. Multiclass models are allowed and both open and closed queuing networks can be used at the software layer. Any solution technique----exact or approximate--can be used at any of the levels. This technique falls in the general nature of fixed-point approximate models and is similar in nature to other approaches. The main difference lies in its simplicity.