Technique for referencing distributed shared memory locally rather than remotely

• US 6,598,130 B2
• Filed: 07/30/2001
• Issued: 07/22/2003
• Est. Priority Date: 07/31/2000
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Harris, Kevin W., Bircsak, John A., Wibecan, Brian F.
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US09/918,251
• Publication Number:
  US 20020087813A1
• Time in Patent Office: 722 Days
• Field of Search: 709/201, 709/213-217, 712/13, 712/14, 712/28, 711/147, 711/170, 711/148, 711/153, 711/202
• US Class Current: 711/147
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

The invention comprises a technique for allocating memory in a multiprocessing computing system. In a first aspect, a method in accordance with the present invention begins by collecting a plurality of descriptions of shared data items. The shared data items are then dynamically allocated into a local virtual address space shared by a plurality of CPUs within a single node. The description of this allocation is the then stored. The method then accesses the stored allocation description to determine the virtual memory address of a shared data item. Whenever a data request is generated, it is determined from this virtual memory address whether the shared data item is available within the shared local virtual address space. If so, the access is performed in the shared local virtual address space. If the data is unavailable in the local virtual address space, it is accessed from a remote memory space.

Claims

1. A method for allocating memory in a multiprocessing computing system including a plurality of nodes, the method comprising:

collecting a plurality of partially completed descriptions of programmer-specified shared data items at program start-up time;

dynamically allocating the shared data items into a local address space shared by a plurality of CPUs within each node;

storing the address of the allocation into each partial description;

determining from the stored allocation address in the stored descriptions a address of a shared data item;

determining from the determined address whether a data request seeking to access the shared data item is seeking data available within the shared local address space

accessing the data from the local address space if the data is determined to be available in the local address space; and

accessing the data from a remote address space if the data is determined to be unavailable in the local address space.

2. The method of claim 1, further comprising compiling a user program to generate the partially completed descriptions of programmer-specified shared data items.

3. The method of claim 1, wherein collecting the plurality of descriptions of shared data items includes collection a plurality of descriptions including the name, size, granularity, and alignment of each of the data items.

4. The method of claim 1, wherein dynamically allocating the shared data items includes allocating the shared items upon detecting the geometry of the hardware configuration.

5. The method of claim 1, wherein storing the description of the allocation includes storing the description in the private memory of each CPU in a computing system.

6. The method of claim 1, wherein the address space is a virtual address space.

7. The method of claim 1, wherein the address is a virtual address.

8. A program storage medium encoded with instructions that, when executed by a computer, perform a method for allocating memory in a multiprocessing computing system including a plurality of nodes, the method comprising:

collecting a plurality of partially completed descriptions of programmer-specified shared data items at program start-up time;

dynamically allocating the shared data items into a local address space shared by a plurality of CPUs within each node;

storing the address of the allocation into each partial description;

determining from the stored allocation address in the stored descriptions a address of a shared data item;

determining from the determined address whether a data request seeking to access the shared data item is seeking data available within the shared local address space

accessing the data from the local address space if the data is determined to be available in the local address space; and

accessing the data from a remote address space if the data is determined to be unavailable in the local address space.

9. The program storage medium of claim 8, wherein the encoded method further comprises compiling a user program to generate the partially completed descriptions of programmer-specified shared data items.

10. The program storage medium of claim 8, wherein collecting the plurality of descriptions of shared data items in the encoded method includes collection a plurality of descriptions including the name, size, granularity, and alignment of each of the data items.

11. The program storage medium of claim 8, wherein dynamically allocating the shared data items in the encoded method includes allocating the shared items upon detecting the geometry of the hardware configuration.

12. The program storage medium of claim 8, wherein storing the description of the allocation in the encoded method includes storing the description in the private memory of each CPU in a computing system.

13. The program storage medium of claim 8, wherein the address space is a virtual address space.

14. The program storage medium of claim 8, wherein the address is a virtual address.

15. A computer programmed to perform a method for allocating memory in a multiprocessing computing system including a plurality of nodes, the method comprising:

collecting a plurality of partially completed descriptions of programmer-specified shared data items at program start-up time;

dynamically allocating the shared data items into a local address space shared by a plurality of CPUs within each node;

storing the address of the allocation into each partial description;

determining from the stored allocation address in the stored descriptions a address of a shared data item;

determining from the determined address whether a data request seeking to access the shared data item is seeking data available within the shared local address space

accessing the data from the local address space if the data is determined to be available in the local address space; and

accessing the data from a remote address space if the data is determined to be unavailable in the local address space.

16. The programmed computer of claim 15, wherein the programmed method further comprises compiling a user program to generate the partially completed descriptions of programmer-specified shared data items.

17. The programmed computer of claim 15, wherein collecting the plurality of descriptions of shared data items in the programmed method includes collection a plurality of descriptions including the name, size, granularity, and alignment of each of the data items.

18. The programmed computer of claim 15, wherein dynamically allocating the shared data items in the programmed method includes allocating the shared items upon detecting the geometry of the hardware configuration.

19. The programmed computer of claim 15, wherein storing the description of the allocation in the programmed method includes storing the description in the private memory of each CPU in a computing system.

20. The programmed computer of claim 15, wherein the address space is a virtual address space.

21. The programmed computer of claim 15, wherein the address is a virtual address.

22. A computing system comprising:

a plurality of SMP nodes, each SMP node including;

a plurality of CPUs; and

a plurality of a private memories, one for each of the CPUs;

a memory space distributed across the SMP nodes and being shared by each of the CPUs; and

a user program resident on the computing system that, when executed, performs the following method;

collecting a plurality of partially completed descriptions of programmer-specified shared data items at program start-up time;

dynamically allocating the shared data items into a local address space shared by a plurality of CPUs within each node;

storing the address of the allocation into each partial description;

determining from the stored allocation address in the stored descriptions a address of a shared data item;

determining from the determined address whether a data request seeking to access the shared data item is seeking data available within the shared local address space;

accessing the data from the local address space if the data is determined to be available in the local address space; and

accessing the data from a remote address space if the data is determined to be unavailable in the local address space.