Section: New Results

Impact of progress threads placement for MPI Non-Blocking Collectives

MPI Non-Blocking Collectives (NBC) allow communication overlap with computation. A good overlapping ratio is obtained when computation and communication are running in parallel. To achieve this, some implementations use progress threads to manage communication tasks. These threads should be bound on different cores to maximize the overlap. Thus, we elaborate several threads placement algorithms. These algorithms have been implemented within the MPC framework, using the hwloc software to get a global view of the machine topology. We propose [18] a thread placement algorithm taking into account the NUMA topology of the machine in order to improve the overlapping ratio of non-blocking collective communications.