1. A computer-implemented method for dynamic performance modeling of computer application services comprising the steps of: abstracting, using a computer system, behavior of a service to three phases: serial, parallel and dormant, thus yielding a Serial Parallel Queueing Network (SPQN) model with a small number of parameters; estimating, using a computer system, the parameters of the model based on stochastic approximation techniques for solving stochastic optimization problems to capture periodic behavior of the service; and using the periodic behavior of the service for performance prediction and computer resource management of the service.