CACHE DEVICE CONTROLLING A STATE OF A CORRESPONDING CACHE MEMORY ACCORDING TO A PREDETERMINED PROTOCOL

It assumes that “SO” represents a state, in which that data in a responsible region storing the data to be accessed most frequently by the corresponding processor is updated in a cache memory to be controlled by a cache device, and other data is stored in other cache memory. In this case, one or more cache devices controlling each of the remaining cache memories changes the state of the data in a region other than the responsible region of the cache memory controlled by itself from “SN” to “I” (invalid). Therefore, in the case where the data designated by the same address is shared by the plurality of cache memories, the data can be invalidated in the cache memories other than the cache memory corresponding to the processor including the designated address in its own responsible region. Therefore, a data sharing rate can be low.