Method and system for scheduling threads to perform real-time operations

An information processing system performs a real-time operation including a combination of a plurality of tasks. The system includes a plurality of processors (12), a unit which stores structural description information (117) and a plurality of programs (111 to 116) describing procedures corresponding to the tasks, the structural description information (117) indicating a relationship in input/output between the programs (111 to 116) and including cost information concerning time required for executing each of the programs (111 to 116), a unit which determines an execution start timing and execution term of each of a plurality of threads for execution of the programs (111 to 116) based on the structural description information (117), and a unit which performs a scheduling operation of assigning the threads to at least one of the processors (12) according to a result of the determining.