Integrated performance views in Charm++: Projections meets TAU

The Charm++ parallel programming system provides a modular performance interface that can be used to extend its performance measurement and analysis capabilities. The interface exposes execution events of interest representing Charm++ scheduling operations, application methods/routines, and communication events for observation by alternative performance modules configured to implement different measurement features. The paper describes the Charm++'s performance interface and how the Charm++ Projections tool and the TAU Performance System can provide integrated trace-based and profile-based performance views. These two tools are complementary, providing the user with different performance perspectives on Charm++ applications based on performance data detail and temporal and spatial analysis. How the tools work in practice is demonstrated in a parallel performance analysis of NAMD, a scalable molecular dynamics code that applies many of Charm++'s unique features.