Software scalability engineering for distributed virtual environments

Distributed Virtual Environments (DVEs) must continue to perform well as users are added. However, DVE performance can become sensitive to user behavior in many ways: their actions, their positions, and even the direction that they look. Two virtual words may be similar in terms of user experience, task efficiency, immersion, and aesthetics. However they may exhibit substantially different performance when many users are logged in. We discuss an approach: Software Scalability Engineering (SSE), that uses load simulation and iterative modeling to locate causes of undesirable performance, experiment with changes, and verify improvements to DVE systems. Presented here is a case study of using the approach to determine the primary bottleneck of the Torque engine. Once that bottleneck is identified, we continue to use SSE to determine the primary cause of the bottleneck and the primary controlling factor for that user. SSE allows us to look at changing both the engine software and the virtual world to improve performance.