Performance Modeling of a Consolidated Java Application Server

System-level virtualization enables multiple servers to be consolidated on a single hardware platform and to share its resources more efficiently. We are currently developing a performance model of a consolidated multi-tier Java application server. The model breaks down the CPU utilization of the workload into servers and transaction types, and use these service time parameters in the network of queues to predict the performance. For the target of initial development, we use SPECjAppServer2004 running on a quad-core server consolidated by Xen. In this paper, we present the current status of performance model development. We have found that the measured CPU utilization seems lower than the actual system saturation level. As a result, the performance model is saturated at a larger system size. We also have found that while the behavior of Manage transactions is most sensitive to the system size, its service times are lower than other transactions. When the CPU utilization of 4-core execution is predicted by the data from 1 to 3-core executions, the prediction errors range from-3.6 to 43.4%, with the largest error occurring in the database domain.