Live Webcast 15th Annual Charm++ Workshop

Over the past 10 years, in progress made as funding permitted, we have developed an approach to predicting performance of applications running on large scale computers using runs on substantially smaller computers. The emulation-followed-by-simulation model of BigSim allows for a spectrum of different resolution levels, both for computation and communication. It also makes it easy for the application developers to use the prediction machinery: one simply runs the application as if running on the future machine, in an emulation mode. This helps catch the code-scalability bugs in the first place. We developed techniques for handling the memry-overload problem or emulation. For simulation, both PDES and sequential simulation is used. One of the main utilities of the model is in predicting the network performance especially as it pertains to contention. I will describe the past experience and potential future plans for the BigSim approach.