1. A method of periodically performing a real-time operation including a plurality of chained tasks using a plurality of processors, the method comprising: inputting structural description information and a plurality of programs describing procedures corresponding to the chained tasks, the structural description information indicating a relationship in input/output between the programs, each of the programs being executed as one task of the chained tasks, the structural description information indicating a program of the programs that is coupled to an input of each of the programs and a program of the programs that is coupled to an output of each of the programs, and the structural description information including cost information indicating an execution term of each of the programs; determining whether a total execution term of the programs is longer than a regular time interval based on the cost information; dividing, if the total execution term is longer than the regular time interval, the chained tasks into a first task group whose total execution term is not longer than a regular time interval and a second task group whose total execution term is not longer than the regular time interval based on the cost information and the relationship in input/output between the programs, each task of the second task group being completed after each task of the first task group is completed; and performing a scheduling operation of periodically assigning the first task group and the second task group to different processors of the processors to periodically execute each task of the first task group at the regular time interval and periodically execute each task of the second task group at the regular time interval with a one-period delay relative to the first task group, the first task group and the second task group being executed in parallel while the second group is delayed one-period relative to the first task group.