Flexible collective communication tuning architecture applied to Open MPI

Collective communications are invaluable to modern high performance applications, although most users of these communication patterns do not always want to know their inner most working. The implementation of the collectives are often left to the middle-ware developer such as those providing an MPI library. As many of these libraries are designed to be both generic and portable the MPI developers commonly offer internal tuning options suitable only for knowledgeable users that allow some level of customization. The work presented in this paper aims not only to provide a very efficient set of collective operations for use with the Open MPI implementation but also to make the control and tuning of them straightforward and flexible. Additionally this paper demonstrates a novel example of the proposed frameworks flexibility, by dynamically tuning a MPI Alltoallv algorithm during runtime.