In response to an all-to-all inter-process communication request from a local process, a computer repeatedly determines a destination server in accordance with a destination-server determination procedure so that, in a same round of destination-server determinations repeatedly performed by the respective servers during all-to-all inter-process communication, the servers determine servers that are different from one another as destination servers. Each time the destination server is determined, the computer sequentially determines a process running on the determined destination server as a destination process. Each time the destination process is determined, the computer obtains transmission data for the destination process from a send buffer in which the transmission data is stored as a result of execution of the local process and transmits the obtained transmission data to the destination server so as to enable reading of the transmission data during execution of the determined destination process in the destination server.