Local region table for storage of information regarding memory access by other nodes

摘要

Information regarding memory access by other nodes within a coherency controller of a node is locally stored. The coherency controller receives a transaction relating a line of local memory of the node. In response to locally determining that the line of the local memory is not being cached by another node and/or has not been modified by another node, the coherency controller processes the transaction without accessing tag directory information regarding the line. A table within the controller may store entries corresponding to local memory sections. Each entry includes a count value tracking a number of lines of the section being cached by other nodes, and a count value tracking a number of lines of the section that have been modified by other nodes. The table may also include flags corresponding to the sections, each flag indicating the validity of the section's contents.