1. A computer system control method for dynamically changing a configuration of the system by computer processing so as to be suitable for content of network traffic information, the method comprising the steps of: storing, in advance, information that indicates tasks and assignment of resources with which the tasks are executed in a stream format so as to be adapted for phases corresponding to a plurality of different contents of the network traffic information; measuring the network traffic information; selecting stream-format resource assignment information that is relatively close to measured network traffic information as a next phase; and switching from the stream-format resource assignment in a selected present phase to stream-format resource assignment in the next phase, in which the resources that have been processed in the stream-format resource assignment in the present phase act as transient alternative tasks in stream-format resource assignment in the next phase.