SNOOP FILTER DIRECTORY MECHANISM IN COHERENCY SHARED MEMORY SYSTEM

Methods and apparatus that may be utilized to maintain coherency of data accessed by both a processor and a remote device are provided. Various mechanisms, such as a remote cache directory, castout buffer, and/or outstanding transaction buffer may be utilized by the remote device to track the state of processor cache lines that may hold data targeted by requests initiated by the remote device. Based on the content of these mechanisms, requests targeting data that is not in the processor cache may be routed directly to memory, thus reducing overall latency.