AfterOMPT: An OMPT-Based Tool for Fine-Grained Tracing of Tasks and Loops

We present AfterOMPT, a new trace-based tool for analyzing the execution of OpenMP applications using the OMPT interface to capture accurate information on loop partitioning, distribution of iteration spaces across workers, task scheduling, and synchronization events. In contrast to previous works that rely on specific, instrumented runtime libraries, our tool is able to collect information from any runtime implementing the OMPT interface. In order to visualize the information from the collected traces, we have extended the Aftermath performance analysis tool with appropriate renderers for OMPT events. We also propose an extension of the OMPT interface for the collection of more detailed information on scheduled OpenMP loops. Experimental results show a tracing overhead of under \(5\%\) for the majority of studied benchmarks, increasing more significantly for those with highly fine-grained workloads.