Resource control for large-scale distributed simulation system over loosely coupled domains

Abstract

Collaborative and distributed simulation environments that span across large interconnection networks, such as the Internet, are a promising way of supporting applications distributed over multiple computing sites. How-ever, communication-intensive distributed applications may suffer from variable communication delays, jitter, and latency experienced over the network. We term a loosely coupled domain the combination of multiple sites connected through an internetwork. In this paper, we focus on large-scale distributed simulations based upon local time warp deployed over several sites connected through an interconnection network (a loosely coupled domain). We propose and study a mechanism to tune elaboration according to varying communication performances, to reduce resource consumption and rollback costs that result from unpredictable network behavior. The mechanism is composed of two parts that operate in a completely distributed way: a local elaboration rate control and a message flow control. The experimental study is conducted through emulation to exert a control on injected delays. Our results show that the mechanism is able to globally tune the entire simulation, so as to reduce the escalation of allocated computational resources and the cost of rollbacks. As delays disappear, the mechanism allows elaboration to resume normal rate.