Non-uniform memory access (NUMA) data processing system having remote memory cache incorporated within system memory

• US 20030009623A1
• Filed: 06/21/2001
• Published: 01/09/2003
• Est. Priority Date: 06/21/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fields, James Stephen Jr., Arimilli, Ravi Kumar, Dodson, John Steven
• Granted Patent: US 6,760,809 B2
• Time in Patent Office: Days
• US Class Current: 711/119
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0817 using directory methods
• CPC Class Codes: G06F 12/0831 using a bus scheme, e.g. with bus monitoring or watching means

Abstract

A non-uniform memory access (NUMA) computer system and associated method of operation are disclosed. The NUMA computer system includes at least a remote node and a home node coupled to an interconnect. The remote node contains at least one processing unit coupled to a remote system memory, and the home node contains at least a home system memory. To reduce access latency for data from other nodes, a portion of the remote system memory is allocated as a remote memory cache containing data corresponding to data resident in the home system memory. In one embodiment, access bandwidth to the remote memory cache is increased by distributing the remote memory cache across multiple system memories in the remote node.

Claims

1. A non-uniform memory access (NUMA) computer system, comprising:

a node interconnect; and

a remote node and a home node coupled to said node interconnect, wherein said remote node includes at least one processing unit coupled to a remote system memory and wherein said home node includes a home system memory, wherein said remote system memory includes a remote memory cache containing data corresponding to data resident in said home system memory.

2. The NUMA computer system of claim 1, said remote node including a plurality of processing units and a plurality of remote system memories, wherein said remote memory cache is distributed among said plurality of remote system memories.

3. The NUMA computer system of claim 1, said remote system memory further comprising a remote memory directory specifying contents of said remote memory cache.

4. The NUMA computer system of claim 1, said remote system memory further comprising a system memory address space.

5. The NUMA computer system of claim 1, wherein said remote system memory comprises one or more dynamic random access memory (DRAM) chips.

6. The NUMA computer system of claim 1, said at least one processing unit including a remote memory cache controller.

7. The NUMA computer system of claim 1, wherein said at least one processing unit has an associated cache hierarchy and wherein said remote memory cache is inclusive of data from said home node held in said cache hierarchy.

8. A remote node for a non-uniform memory access (NUMA) computer system including a home node coupled to the remote node by a node interconnect, said remote node comprising:

a local interconnect;

a node controller coupled to said local interconnect and the node interconnect;

at least one processing unit coupled to said local interconnect; and

a remote system memory coupled to said at least one processing unit, wherein said remote system memory includes a remote memory cache containing data corresponding to data resident in a home system memory in the home node.

9. The remote node of claim 8, said remote node including a plurality of processing units and a plurality of remote system memories, wherein said remote memory cache is distributed among said plurality of remote system memories.

10. The remote node of claim 8, said remote system memory further comprising a remote memory directory specifying contents of said remote memory cache.

11. The remote node of claim 8, said remote system memory further comprising a system memory address space.

12. The remote node of claim 8, wherein said remote system memory comprises one or more dynamic random access memory (DRAM) chips.

13. The remote node of claim 8, said at least one processing unit including a remote memory cache controller.

14. The remote node of claim 8, wherein said at least one processing unit has an associated cache hierarchy and wherein said remote memory cache is inclusive of data from said home node held in said cache hierarchy.

16. The method of claim 15, wherein said remote node includes a plurality of processing units and a plurality of remote system memories, and wherein creating a remote memory cache comprises creating a remote memory cache distributed among said plurality of remote system memories.

17. The method of claim 15, and further comprising creating within said remote system memory a remote memory directory specifying contents of said remote memory cache.

18. The method of claim 15, and further comprising allocating a portion said remote system memory as system memory address space.

19. The method of claim 15, wherein creating a remote memory cache in said home system memory comprises creating said remote memory cache within one or more dynamic random access memory (DRAM) chips.

20. The method of claim 15, wherein said accessing step comprises accessing said remote memory caches utilizing a remote memory cache controller within said at least one processing unit.

21. The method of claim 15, wherein said at least one processing unit has an associated cache hierarchy and wherein creating said remote memory cache comprises creating a remote memory cache that is inclusive of data from said home node held in said cache hierarchy.

15. A method operating a non-uniform memory access (NUMA) computer system including a remote node and a home node coupled by a node interconnect, said method comprising:

in a remote system memory in said remote node, creating a remote memory cache containing data corresponding to data resident in a home system memory in said home node; and

in response to a request by a processing unit that specifies an address associated with a storage location in said home system memory, servicing said request by accessing said remote memory in said remote system memory.