A trace controller receives data access information during load instruction execution and ID (AID) of a load/store buffer to store the data access information during load instruction execution. Then, it generates trace control information TC based on the received data access information and selects a buffer to store the generated trace control information from a plurality of trace control buffers according to the received AID. After that, it receives read data information after load instruction execution and ID (RID) of a load/store buffer used for load instruction execution. Finally, it selects a buffer storing the trace control information TC from the plurality of trace control buffers according to the RID.