1. A multiprocessor system comprising: a plurality of processors which send and receive predetermined information to and from each other; and a shared memory which is shared and accessed by said plurality of processors one after another, and wherein each of said plurality of processors requests at least one of other processors included in said plurality of processors to access said shared memory that is to be done by the at least one of other processors, in a case where each of said plurality of processors has accessed said shared memory.