COMMAND SELECTION METHOD AND ITS APPARATUS, COMMAND THROW METHOD AND ITS APPARATUS

• US 20090064153A1
• Filed: 08/27/2008
• Published: 03/05/2009
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: ISHIMURA, Naoya, Unno, Hideyuki
• Granted Patent: US 8,161,274 B2
• Time in Patent Office: Days
• US Class Current: 718/103
• CPC Class Codes: G06F 2209/5021 Priority
• CPC Class Codes: G06F 2209/507 Low-level
• CPC Class Codes: G06F 9/3836 Instruction issuing, e.g. dynamic instruction scheduling or out of order instruction execution
• CPC Class Codes: G06F 9/5005 to service a request
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals

Abstract

When selecting one command within a processor from a plurality of command queues vested with order of priority, the order of priority assigned to the plurality of command queues is dynamically changed so as to select a command, on a priority basis, from a command queue vested with a higher priority from among the plurality of command queues in accordance with the post-change order of priority.

Claims

1. A command selection method for selecting, within a processor, one command from a plurality of command queues vested with order of priority, comprising:

changing dynamically the order of priority assigned to the plurality of command queues; and

selecting a command from a command queue in which a higher priority exists from among the plurality of command queues in accordance with the post-change order of priority.

2. The command selection method according to claim 1, wherein

said order of priority is temporarily changed at random.

3. The command selection method according to claim 1, further comprising

counting, for each of command queue, a number of times in which a command has not been selected continuously by other command queue, and

changing said order of priority temporarily when the number of times reaches a predetermined value.

4. The command selection method according to claim 1, wherein

said command is a command output externally to said processor as a request.

5. A command selection apparatus which is an apparatus mounted on a processor for selecting one command from a plurality of command queues vested with order of priority, comprising:

an order change unit for dynamically changing order of priority assigned to the plurality of command queues; and

a command selection unit for selecting a command from the plurality of command queues in accordance with a post-change order priority if the order of priority is changed by the order change unit.

6. The command selection apparatus according to claim 5, wherein

said order change unit counts, for each of command queue, a number of times in which a command has not been selected continuously by other command queue,

changes said order of priority temporarily when the number of times reaches a predetermined value, and

makes said command selection unit select a command from a command queue of which the number of times has reached a predetermined value.

7. A command throw method used for throwing a command into a pipeline process unit mounted on a processor, comprising:

monitoring rethrowing of command for each priority of the command threw into the pipeline process unit; and

changing timings of throwing the command into the pipeline process unit on the basis of the monitoring result.

8. The command throw method according to claim 7, wherein

said monitoring is carried out by counting, for each priority designated to said command, a number of times in which the command has been re-throw, and

said timings are changed by deterring throwing a command to said pipeline process unit for a predetermined period of time if a command of a priority of which the number of times has reached a predetermined value.

9. A command throw apparatus which is an apparatus mounted on a processor for throwing a command into a pipeline process unit for performing pipeline processing, comprising:

a re-throw monitoring unit for monitoring the re-throwing of a command for each priority of commands threw into the pipeline process unit; and

a throw unit for changing timings of throwing the command into the pipeline process unit on the basis of a monitoring result of the re-throw monitoring unit.