Cactus and Visapult: An ultra-high performance grid-distributed visualization architecture
using connectionless protocols
This past decade has seen rapid growth in the size, resolution, and complexity of Grand Challenge simulation codes. This trend is accompanied by a trend towards multinational, multidisciplinary teams who carry out this research in distributed teams, and the corresponding growth of Grid infrastructure to support these widely distributed Virtual Organizations. As the number and diversity of distributed teams grow, the need for visualization tools to analyze and display multi-terabyte, remote data becomes more pronounced and more urgent. One such tool that has been successfully used to address this problem is Visapult. Visapult is a parallel visualization tool that employs Grid-distributed components, latency tolerant visualization and graphics algorithms, along with high performance network I/O in order to achieve effective remote analysis of massive datasets. In this paper we discuss improvements to network bandwidth utilization and responsiveness of the Visapult application that result from using connectionless protocols to move data payload between the distributed Visapult components and a Grid-enabled, high performance physics simulation used to study gravitational waveforms of colliding black holes: The Cactus code. These improvements have boosted Visapult's network efficiency to 88-96 percent of the maximum theoretical available bandwidth on multi-gigabit Wide Area Networks, and greatly enhanced interactivity. Such improvements are critically important for future development of effective interactive Grid applications.