Graphics system with virtual memory pages and non-power of two number of memory elements

• US 8,072,463 B1
• Filed: 10/04/2006
• Issued: 12/06/2011
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: NVIDIA Corporation
• Inventors: Van Dyke, James M., Edmondson, John H., Montrym, John S.
• Primary Examiner(s): Wu, Xiao M.
• Assistant Examiner(s): Welch, David T
• Application Number:
  US11/538,755
• Time in Patent Office: 1,889 Days
• Field of Search: 345/568, 345/540, 345/543, 345/544, 711/117, 711/127, 711/157, 711/203
• US Class Current: 345/568
• CPC Class Codes: G06F 12/0607 Interleaved addressing
• CPC Class Codes: G06F 12/10 Address translation

Abstract

A graphics system utilizes virtual memory pages and has a partitioned graphics memory that includes memory elements. The system supports having an non-power of two number of active memory elements. Additionally, a partition swizzling operation is used to adjust the partition numbers associated with individual units of virtual memory allocation on particular virtual memory pages to achieve a selected partition interleaving pattern.

Claims

1. A graphics system, comprising:

a partitioned graphics memory having a plurality of independently addressable partitions each including at least one dynamic random access memory (DRAM), with a total number of operative DRAMs being a non power of two number, and at least one of said partitions including multiple DRAMs;

a graphics processing unit coupled to said partitioned graphics memory;

an address translation module in said graphics processing unit performing an address translation mapping virtual addresses to physical addresses and determining individual partitions associated with memory accesses for individual units of virtual memory allocation, said address translation module configured to perform a first modulo operation to select an individual partition in said partitioned graphics memory, said address translation module configured to perform a second modulo operation to select an individual DRAM included in said selected partition;

said graphics system performing partition interleaving in which data for an individual unit of virtual memory allocation is assigned to one partition and different individual units of virtual memory allocation are assigned to different partitions;

said graphics system performing a partition swizzling operation to adjust the partition numbers associated with said individual units of virtual memory allocation on particular virtual memory pages to achieve a selected partition interleaving pattern.

2. The graphics system of claim 1, wherein said selected partition interleaving pattern is a checkerboard pattern that prevents rows or columns of said individual units of virtual memory allocation on a virtual page from being assigned to the same partition.

3. The graphics system of claim 1, wherein said swizzling operation is based on the number of partitions in said partitioned memory such that said graphics system supports both a power of two number of partitions and a non power of two number of partitions.

4. The graphics system of claim 1, wherein said partition interleaving is based on the total number of said plurality of partitions and a partition offset indicating the first partition for a particular virtual memory page.

5. The graphics system of claim 4, wherein a partition offset is either stored as part of a page table entry or calculated at translation time.

6. The graphics system of claim 4, wherein said partition interleaving is further based on partition stride indicative of an integer number of individual units of virtual memory allocation.

7. The graphics system of claim 6, wherein said partition stride is stored as a page table entry.

8. The graphics system of claim 1, wherein said graphics system further performs bank swizzling to optimize bank utilization.

9. The graphics system of claim 1, wherein a memory format organizes said individual units of virtual memory allocation on particular virtual memory pages into blocks, said blocks further organized into rows.

10. The graphics system of claim 1, wherein said address translation module is configured to perform said first modulo operation based on a subset of physical address bits and a total number of partitions to arrive at a partition number, and said selected partition includes a non power of two number of DRAMs.

11. A graphics system, comprising:

a partitioned graphics memory having a plurality of independently addressable partitions each including at least one dynamic random access memory (DRAM), with a total number of operative DRAMs being a non power of two number, and at least one of said partitions including multiple DRAMs;

a central processing unit (CPU) utilizing virtual memory addressing in which at least one type of graphics data is represented on virtual pages as virtual tiles having units of virtual memory allocation organized according to a memory format; and

a graphics processing unit coupled to said partitioned graphics memory;

an address translation module in said graphics processing unit performing an address translation mapping physical addresses to individual partitions and DRAM addresses within partitions, said address translation module being programmable to specify a number of partitions in said partitioned graphics memory, said address translation being based on said specified number of partitions, said address translation module configured to perform a first modulo operation to select an individual partition in said partitioned graphics memory, said address translation module configured to perform a second modulo operation to select an individual DRAM included in said selected partition;

said graphics system performing partition interleaving in which data for an individual unit of virtual memory allocation is assigned to one partition and different individual units of virtual memory allocation are assigned to different partitions;

said graphics system performing a partition swizzling operation to adjust the partition numbers associated with said individual units of virtual memory allocation on particular virtual memory pages to achieve a selected partition interleaving pattern.

12. The graphics system of claim 11, wherein said selected partition interleaving pattern is a checkerboard pattern that prevents rows of said individual units of virtual memory allocation on a virtual page from being assigned to the same partition.

13. The graphics system of claim 11, wherein said swizzling operation is based on the specified number of partitions in said partitioned memory such that said graphics system supports both a power of two number of partitions and a non power of two number of partitions.

14. The graphics system of claim 11, wherein said partition interleaving is based on the specified number of partitions and a partition offset indicating the first partition for a particular virtual memory page.

15. The graphics system of claim 14, wherein said partition offset is stored as part of a page table entry.

16. The graphics system of claim 14, wherein said partition interleaving is further based on partition stride indicative of an integer number of individual units of virtual memory allocation.

17. The graphics system of claim 16, wherein said partition stride is stored as part of a page table entry.

18. The graphics system of claim 11, wherein said graphics system further performs bank swizzling to optimize bank utilization.

19. The graphics system of claim 11, wherein said memory format organizes said individual units of virtual memory allocation into blocks, said blocks further organized into rows.

20. The graphics system of claim 11, further comprising a non-volatile memory to store an indication corresponding to said specified number of partitions, and said specified number of partitions is different from a total number of partitions in said partitioned graphics memory.