A Memory Saving Communication Method Using Remote Atomic Operations

The MPI library for the K computer introduced a memory saving protocol. However, the protocol still requires memory in proportion to the number of MPI processes and a memory shortage can occur when the number of processes reaches millions or tens of millions. In order to solve the problem, we propose the shared receive buffer method which is a new communication protocol using remote atomic operations. This method is easily implemented if an interconnect has remote memory access and remote atomic memory operation. We implemented shared receive buffer method on PRIMEHPC FX100 system and evaluated. The per process memory usage of the proposed method is about one tenth compared to that of existing method.