Memory bank group interleaving
Memory utilization in an SDRAM system may be improved by increasing memory bank group and memory bank interleaving. Memory bank group interleaving and memory bank interleaving may be increased by a memory controller generating a physical memory address in which the bank group address bits are positioned nearer the LSB of the physical memory address than the MSB. Alternatively, or in addition to positioning the bank group address bits in such a manner, memory bank group interleaving and memory bank interleaving may be increased by hashing the bank group address bits and bank address bits of the physical memory address with row address bits of the initial physical memory address, A rank address bit may also be involved in the hashing.
1. A method for memory bank interleaving in a synchronous dynamic random access memory (SDRAM) system, comprising:
generating, by a memory controller, an initial physical memory address, the initial physical memory address comprising a plurality of bank group address bits, a plurality of bank address bits and a plurality of row bits;
generating, by the memory controller, a plurality of new bank group address bits and a plurality of new bank address bits by a primitive polynomial hash algorithm that utilizes all row bits; the primitive polynomial hash algorithm comprising: a string of bitwise exclusive-OR operations among a plurality of row bits and each bank group address bit, and a string of bitwise exclusive-OR operations among a plurality row bits and each bank address bit;
generating a modified physical memory address by replacing the plurality of bank group address bits and the plurality of bank address bits of the initial physical memory address with the respective plurality of new bank group address bits and plurality of new bank address bits, while the plurality of row bits of the physical memory address remain unchanged; and
providing, by the memory controller, the modified physical memory address to an SDRAM chip.
2. The method of claim 1 , wherein primitive polynomial hash algorithm comprises applying a poly19 hash.
3. The method of claim 1 , wherein the bank group address bits are in 11th and 12th bit positions of the initial and modified physical memory addresses, and the bank address bits are in 13th and 14th bit positions of the initial and modified physical memory addresses.
4. The method of claim 1 , wherein the bank group address bits are in 7th and 11th bit positions of initial and modified physical memory addresses, and the bank address bits are in 13th and 14th bit positions of the initial and modified physical memory addresses.
5. The method of claim 1 , wherein the primitive polynomial hash algorithm comprises hashing the plurality of bank group address bits in combination with the plurality of bank address bits in combination with a rank address bit with the row address bits.
6. The method of claim 5 , wherein the primitive polynomial hash algorithm comprises applying a poly37 hash.
7. A system for memory bank interleaving in a synchronous dynamic random access memory (SDRAM) system, comprising:
a memory controller configured to generate an initial physical memory address, the initial physical memory address comprising a plurality of bank group address bits, a plurality of bank address bits and a plurality of row bits, and the memory controller further configured to generate a plurality of new bank group address bits and a plurality of new bank address bits by a primitive polynomial hash algorithm that utilizes all row bits; the primitive polynomial hash algorithm comprising: a string of bitwise exclusive-OR operations among a plurality of row bits and each bank group address bit, and a string of bitwise exclusive-OR operations among a plurality of row bits and each bank address bit;
the memory controller further configured to generate a modified physical memory address by replacing the plurality of bank group address bits and plurality of bank address bits of the initial physical memory address with the plurality of new bank group address bits and the plurality of new bank address bits, while the plurality of row bits of the physical memory address remain unchanged; and
wherein the memory controller is further configured to provide the modified physical memory address to an SDRAM chip.
8. The system of claim 7 , wherein the primitive polynomial hash algorithm comprises applying a poly19 hash.
9. The system of claim 7 , wherein the primitive polynomial hash algorithm comprises hashing the plurality of bank group address bits in combination with the plurality of bank address bits in combination with a rank address bit with the row address bits.
10. The system of claim 9 , wherein the bank group address bits are in 11th and 12th bit positions of the initial and modified physical memory addresses, and the bank address bits are in 13th and 14th bit positions of the initial and modified physical memory addresses.
11. The system of claim 9 , wherein the bank group address bits are in 7th and 11th bit positions of the initial and modified physical memory addresses, and the bank address bits are in 13th and 14th bit positions of the initial and modified physical memory addresses.
12. The system of claim 7 , wherein the primitive polynomial hash algorithm comprises applying a poly37 hash.