Damaris/Viz: A nonintrusive, adaptable and user-friendly in situ visualization framework

Abstract

Reducing the amount of data stored by simulations will be of utmost importance for the next generation of large-scale computing. Accordingly, there is active research to shift analysis and visualization tasks to run in situ, that is, closer to the simulation via the sharing of some resources. This is beneficial as it can avoid the necessity of storing large amounts of data for post-processing. In this paper, we focus on the specific case of in situ visualization where analysis codes are collocated with the simulation's code and run on the same resources. It is important for an in situ technique to require minimum modifications to existing codes, be adaptable, and have a low impact on both run times and resource usage. We accomplish this through the Damaris/Viz framework, which provides in situ visualization support to the Damaris I/O middleware. The use of Damaris as a bridge to existing visualization packages allows us to (1) reduce code moditication to a minimum for existing simulations, (2) gather capabilities of several visualization tools to offer a unified data management interface, (3) use dedicated cores to hide the run time impact of in situ visualization and (4) efficiently use memory through a shared-memory-based communication model. Experiments are conducted on Blue Waters and Grid'5000 to visualize the CM1 atmospheric simulation and the Nek5000 CFD solver.

A Flexible Framework for Asynchronous in Situ and in Transit Analytics for Scientific Simulations

“…The molecular dynamics simulation we rely on departs from the type of simulations usually used to benchmark other in-situ frameworks like [24] or [37]. Molecular dynamics simulations are characterizer by high frequencies (up to 1061Hz in our case) compared to simulations runnings in between 1Hz and 1/20Hz.…”

High-Performance Computing: Dos and Don’ts

“…These interfaces allow a fixed coupling between the simulation and the visualization and integrate large parts of the visualization libraries into the program code of the simulation. Recent developments [75,76] favor methods for loose coupling as tight coupling proves to be inflexible and susceptible to faults. Here, the simulation program and visualization are independent applications that only exchange certain data among each other via clearly defined interfaces.…”

Performance Analysis, Design Considerations, and Applications of Extreme-Scale In Situ Infrastructures

“…Recent examples include Damaris/Viz [24], Freeprocessing [25] and Strawman [26]. Damaris/Viz's API has sharing semantics for arrays to be used by both the simulation and the in situ application safely.…”