In-situ visualization for global hybrid simulations

Abstract

Petascale simulations have become mission critical in diverse areas of science and engineering. Knowledge discovery from such simulations remains a major challenge and is becoming more urgent as the march towards ultra-scale computing with millions of cores continues. One major issue with the current paradigm of running the simulations and saving the data to disk for post-processing is that it is only feasible to save the data at a small number of time slices. This low temporal resolution of the saved data is a serious handicap in many studies where the time evolution of the system is of principle interest. One way to address this I/O issue is through in-situ visualization strategies. The idea is to minimize data storage by extracting important features of the data and saving them, rather than raw data, at high temporal resolution. Parallel file systems of current petascale and future exascale systems are expensive shared resources and need to be utilized effectively, and similarly archival storage can be limited and both of these will benefit from in-situ visualization as it will lead to intelligent way of utilizing storage. In this paper, we present preliminary results from our in-situ visualization for global hybrid (electron fluid, kinetic ions) simulations which are used to study the interaction of the solar wind with planetary magnetospheres such as the Earth and Mercury. In particular, we examine the overhead and effect on code performance associated with the inline computations associated with in-situ visualization.