Section: New Results

Communication monitoring in OpenMPI

Monitoring data exchanges is critical when it comes to optimize process placement in a large scale environment. We participated in adding in Open-MPI, which is one of the major MPI implementation, a fine grain, point-to-point monitoring component that keeps track of message exchanges. Unlike implementations using PMPI operations, the layer in which this monitoring acts allow us to record at a lower level the effective data communications, for example, after the covering tree has been calculated. This component has been enriched with a complete coverage of collectives, point-to-point and one-sided communications. This component also reports informations about message sizes distribution. Monitored informations can be accessed by using MPI_Tools interface, or by dumping data in files.