Scaleable shared-memory multi-processor computer system having repetitive chip structure with efficient busing and coherence controls

Abstract

A novel structure for a highly-scaleable high-performance shared-memory computer system having simplified manufacturability. The computer system contains a repetition of system cells, in which each cell is comprised of a processor chip and a memory subset (having memory chips such as DRAMs or SRAMs) connected to the processor chip by a local memory bus. A unique type of intra-nodal busing connects each system cell in each node to each other cell in the same node. The memory subsets in the different cells need not have equal sizes, and the different nodes need not have the same number of cells. Each node has a nodal cache, a nodal directory and nodal electronic switches to manage all transfers and data coherence among all cells in the same node and in different nodes. The collection of all memory subsets in the computer system comprises the system shared memory, in which data stored in any memory subset is accessible to the processors on the other processor chips in the system. Each location in the system shared memory has a unique real address, which may be used by any processor in the system. Thus, the same memory addresses may be used in the executable instructions of all processors in the system. The nodal directories automatically manage the coherence of all data being changed in all processor caches in the computer system, regardless of where the data is stored in the shared memory of the system and regardless of which cell in the system contains the processor changing the data to provide data coherence across all nodes in the computer system.