Visualization of OpenMP~* Task Dependencies Using Intel Advisor - Flow Graph Analyzer

摘要

With the introduction of task dependences, the OpenMP API considerably extended the expressiveness of its task-based parallel programming model. With task dependences, programmers no longer have to rely on global synchronization mechanisms like task barriers. Instead they can locally synchronize a restricted subset of generated tasks by expressing an execution order through the depend clause. With the OpenMP tools interface of Technical Report 6 of the OpenMP API specification, it becomes possible to monitor task creation and execution along with the corresponding dependence information of these tasks. We use this information to construct a Task Dependence Graph (TDG) for the Flow Graph Analyzer (FGA) tool of Intel Advisor. The TDG representation is used in FGA for deriving metrics and performance prediction and analysis of task-based OpenMP codes. We apply the FGA tool to two sample application kernels and expose issues in their usage of OpenMP tasks.