Instrumenting LogP parameters in GM: implementation and validation

This paper describes an apparatus which can be used to vary communication performance parameters for MPI applications, and provides a tool to analyze the impact of communication performance on parallel applications. Our apparatus is based on Myrinet (along with GM). We use an extension of the LogP model to allow higher flexibility in determining the parameter(s) to which parallel applications may be more sensitive. We show that individual communication parameters can be controlled within a small percentage error, and that the other parameters remain unchanged.