Nodes and NUMA computer system includes a method of operating a non-uniform memory access (NUMA) computer system memory controller, a memory system, the memory system

摘要

A computer system includes a home node and one or more remote nodes coupled by a node interconnect. The home node includes a local interconnect, a node controller coupled between the local interconnect and the node interconnect, a home system memory, a memory directory including a plurality of entries, and a memory controller coupled to the local interconnect, the home system memory and the memory directory. The memory directory includes a plurality of entries that each provide an indication of whether or not an associated data granule in the home system memory has a corresponding cache line held in at least one remote node. The memory controller includes demand invalidation circuitry that, responsive to a data request for a requested data granule in the home system memory, reads an associated entry in the memory directory and issues an invalidating command to at least one remote node holding a cache line corresponding to the requested data granule. In addition, the memory controller includes directory scrubbing logic that, independently of any data request, periodically reads entries in the memory directory and, responsive to an entry indicating at least one remote node holds a cache line corresponding to the associated data granule, issues a flush query to the at least one remote node to request deallocation of the cache line corresponding to the associated data granule.