Method and apparatus for determining priorities in direct memory access device having multiple direct memory access request blocks

• US 8,065,447 B2
• Filed: 08/31/2007
• Issued: 11/22/2011
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lim, Jae-young, Ryu, Eun-jin, Kang, Dong-soo
• Primary Examiner(s): Kindred; Alford
• Assistant Examiner(s): Unelus; Ernest
• Application Number:
  US11/896,453
• Publication Number:
  US 20080183913A1
• Time in Patent Office: 1,544 Days
• Field of Search: 710/40, 710/116, 710/25, 710/123
• US Class Current: 710/22
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence

Abstract

A priority determining method and apparatus can reduce a total waiting time of DMA request blocks by granting priority to each of Direct Memory Access (DMA) request blocks transmitting a DMA request signal, based on Data Transfer Amounts (DTAs) of the DMA request blocks and Arrival Times (ATs) of the DMA request signals, counting the number of priority changes of each of DMA request blocks whose priority is changed in the priority granting process, and if a DMA request signal is received from a new DMA request block, determining priorities of the DMA request blocks based on the counted the number of priority changes.

Claims

1. A priority determining method, comprising:

granting priority to each of Direct Memory Access (DMA) request blocks transmitting a DMA request signal, based on Data Transfer Amounts (DTAs) of the DMA request blocks and Arrival Times (ATs) of the DMA request signals;

counting the number of times the granted priority is changed for each of the DMA request blocks whose granted priority is changed in the granting priority; and

if a DMA request signal is received from a new DMA request block, determining priorities of the DMA request blocks based on at least one of the DTAs and ATs considering the counted number of times the granted priority has changed for each of the DMA request blocks whose priority is changed,

wherein an arrival order of DMA request blocks is determined based on the ATs, and the priorities of the DMA request blocks are determined using the arrival order to reduce a total Waiting Time (WT),

wherein the determining priorities of the DMA request blocks comprises;

comparing the counted number of times the granted priority has changed for each of the DMA request blocks whose priority is changed, with a predetermined count threshold; and

determining priorities of the DMA request blocks and the new DMA request block based on at least one of the DTAs and ATs of the DMA request signals according to a result of the comparison.

2. The priority determining method of claim 1, wherein if the counted number of priority changes of one of the DMA request blocks whose priority is changed is equal to or greater than the predetermined count threshold in the determining priorities, the priorities of the DMA request blocks are maintained as the priorities, and priority of the new DMA request block is determined based on an AT of its DMA request signal.

3. The priority determining method of claim 1, wherein if the counted number of priority changes of one of the DMA request blocks whose priority is changed is equal to or greater than the predetermined count threshold in the determining priorities, the priority of the DMA request block whose counted number of priority changes is equal to or greater than the predetermined count threshold among the DMA request blocks is maintained as it is and priorities of the new DMA request block and the other DMA request blocks remaining by excluding the DMA request block maintaining its existing priority are determined based on DTAs.

4. The priority determining method of claim 1, wherein the granting priority comprises granting higher priority to a DMA request block having a smaller DTA.

5. The priority determining method of claim 1, wherein the new DMA request block and the DMA request blocks are processors which can perform data computation.

6. The priority determining method of claim 1, wherein the predetermined count threshold can be changed.

7. A non-transitory computer readable recording medium storing a computer readable program for executing the priority determining method of claim 1.

8. A priority determining apparatus, comprising:

a priority pre-processing unit to grant priority to each of Direct Memory Access (DMA) request blocks transmitting a DMA request signal, based on Data Transfer Amounts (DTAs) of the DMA request blocks and Arrival Times (ATs) of the DMA request signals;

a counter to count the number of times the granted priority is changed for each of the DMA request blocks whose priority is changed in the priority granting process; and

a priority determining module to determine priorities of the DMA request blocks based on at least one of the DTAs and ATs considering the counted number of times the granted priority has changed for each of the DMA request blocks whose priority is changed, when a DMA request signal is received from a new DMA request block,

wherein an arrival order of DMA request blocks is determined based on the ATs, and the priorities of the DMA request blocks are determined using the arrival order to reduce a total Waiting Time (WT), and

wherein the priority determining module comprises;

a comparator to compare the counted number of times the granted priority has changed for each of the DMA request blocks whose priority is changed, with a predetermined count threshold; and

a priority determiner to determine priorities of the DMA request blocks and the new DMA request block based on at least one of the DTAs and ATs of the DMA request signals according to a result of the comparison.

9. The priority determining apparatus of claim 8, wherein if the counted number of priority changes of one of the DMA request blocks whose priority is changed is equal to or greater than the predetermined count threshold, the priority determiner maintains the priorities of the DMA request blocks as the priorities and determines priority of the new DMA request block based on an AT of its DMA request signal.

10. The priority determining apparatus of claim 8, wherein if the counted number of priority changes of one of the DMA request blocks whose priority is changed is equal to or greater than the predetermined count threshold, the priority determiner maintains the priority of the DMA request block whose counted number of priority changes is equal to or greater than the predetermined count threshold among the DMA request blocks as it is and determines priorities of the new DMA request block and the other DMA request blocks remaining by excluding the DMA request block maintaining its existing priority based on DTAs.

11. The priority determining apparatus of claim 8, wherein the priority pre-processing unit grants higher priority to a DMA request block having a smaller DTA.

12. The priority determining apparatus of claim 8, wherein the new DMA request block and the DMA request blocks are processors which can perform data computation.

13. The priority determining apparatus of claim 8, wherein the predetermined count threshold can be changed.

14. A priority determining method, comprising:

granting priority to each of Direct Memory Access (DMA) request blocks; and

transmitting a DMA request signal, based on Data Transfer Amounts (DTAs) of the DMA request blocks, and Arrival Times (ATs) considering a number of times a granted priority is changed for each of the DMA request blocks,

wherein an arrival order of DMA request blocks is determined based on the ATs, and priorities of the DMA request blocks are determined using the arrival order to reduce a total Waiting Time (WT),

wherein the transmitting a DMA request signal comprises;

comparing the number of times the granted priority has changed for each of the DMA request blocks, with a predetermined count threshold; and

transmitting a DMA request signal, based on the DTAs of the DMA request blocks and the ATs, according to a result of the comparison.

15. The priority determining method of claim 14,

wherein the granting priority comprises granting higher priority to a DMA request block having a smaller DTA.