1. A multi-core processor system comprising: a plurality of cores that execute a process having a plurality of threads; and a memory accessible to the plurality of cores, wherein a first core of the plurality of cores generates, when the process is executed by a second core other than the first core, a monitoring thread that saves to the memory state information including an executed state of the process, and causes the second core to suspend an execution of the process before the first core executes the monitoring thread.