Patent ID: 8856457
Filing Date: 2014-10-07
Classification: G06F

Abstract:
1. Information processing system comprising: a first CPU unit having a first CPU and a first cache memory that stores cache tag information and cache data; a second CPU unit having a second CPU and a second cache memory that stores cache tag information and cache data and has a different capacity from a capacity of the first cache memory; and a system controller that is connected to the first CPU unit and the second CPU unit and searches a third cache memory that stores a copy of the cache tag information in the first cache memory and a fourth cache memory that stores a copy of the cache tag information in the second cache memory according to a request to the first cache memory and the second cache memory from the first CPU unit and the second CPU unit, wherein the system controller comprising: a cache synchronization unit that monitors whether or not preceding request and subsequent request require same cache address by monitoring range of busy that is set and make a retry of the subsequent request that requires the same cache address as the preceding request to a CPU that has required when receiving the subsequent request before completing update of the copy of the cache tag information by the preceding request; and a setting unit that sets different monitoring ranges of the busy between the third cache tag memory and the fourth cache tag memory to the cache synchronization unit.