Apparatus and method for software specified power management performance using low power virtual threads

1. A processor, comprising:

a software control module specifying a power performance metric;

a policy manager responsive to said software control module; and

a dispatch scheduler responsive to said policy manager to operate said processor in accordance with said power performance metric;

wherein said dispatch scheduler is within the core of said processor and said policy manager is a customizable multi-thread scheduling unit outside the core of said processor;

wherein said policy manager specifies a low power virtual thread responsive to said power performance metric, said dispatch scheduler scheduling said low power virtual thread but never selecting said low power virtual thread;

wherein said policy manager instructs selected threads to be shut down in response to said power performance metric and said dispatch scheduler shuts down said selected threads.

2. The processor of claim 1 wherein said power performance metric is an instructions per unit time parameter.

3. The processor of claim 1 wherein said policy manager tracks the operation of said low power virtual thread.

4. The processor of claim 1 wherein said dispatch scheduler specifies that no operations are performed in pipeline positions corresponding to pipeline positions of said low power virtual thread.

5. A processor, comprising:

a software control module specifying a power performance metric;

a policy manager responsive to said software control module; and

a dispatch scheduler responsive to said policy manager to operate said processor in accordance with said power performance metric;

wherein said dispatch scheduler is within the core of said processor and said policy manager is a customizable multi-thread scheduling unit outside the core of said processor;

wherein said policy manager instructs selected threads to be shut down in response to said power performance metric and said dispatch scheduler shuts down said selected threads.

6. The processor of claim 5 wherein said policy manager instructs selected threads to be shut down on a cycle-by-cycle basis.

7. A processor, comprising:

a software control module specifying a power performance metric;

a bifurcated thread scheduler including a multi-thread internal processor core component and a customizable multi-thread external processor core component in direct communication with said software control module, said bifurcated thread scheduler operating said processor in accordance with said power performance metric;

wherein said customizable multi-thread external processor core component specifies a low power virtual thread responsive to said power performance metric, said multi-thread internal processor core component scheduling said low power virtual thread but never selecting said low power virtual thread.

8. The processor of claim 7 wherein said power performance metric is an instructions per unit time parameter.

9. The processor of claim 7 wherein said customizable multi-thread external processor core component tracks the operation of said low power virtual thread.

10. The processor of claim 7 wherein said multi-thread internal processor core component specifies that no operations are performed in pipeline positions corresponding to pipeline positions of said low power virtual thread.

11. A processor, comprising:

a software control module specifying a power performance metric;

a bifurcated thread scheduler including a multi-thread internal processor core component and a customizable multi-thread external processor core component in direct communication with said software control module, said bifurcated thread scheduler operating said processor in accordance with said power performance metric;

wherein said customizable multi-thread external processor core component instructs selected threads to be shut down in response to said power performance metric and said multi-thread internal processor core shuts down said selected threads.

12. The processor of claim 11 wherein said customizable multi-thread external processor core component instructs selected threads to be shut down on a cycle-by-cycle basis.

13. A method of operating a processor, comprising:

specifying a power performance metric via software control;

responding to said power performance metric at a customizable multi-thread external processor core component; and

implementing said power performance metric with a multi-thread internal processor core component responsive to said customizable multi-thread external processor core component;

wherein responding includes specifying a low power virtual thread responsive to said power performance metric, and implementing includes scheduling said low power virtual thread but never selecting said low power virtual thread.

14. The method of claim 13 wherein specifying includes specifying an instructions per unit time parameter.

15. The method of claim 13 further comprising stopping operations in pipeline positions corresponding to pipeline positions of said low power virtual thread.

16. A method of operating a processor, comprising:

specifying a power performance metric via software control;

responding to said power performance metric at a customizable multi-thread external processor core component; and

implementing said power performance metric with a multi-thread internal processor core component responsive to said customizable multi-thread external processor core component;

wherein responding includes instructing selected threads to be shut down in response to said power performance metric, wherein responding includes instructing selected threads to be shut down on a cycle-by-cycle basis.

17. A computer readable storage medium, comprising executable instructions to:

define a policy manager responsive to a power performance metric from a software control module, wherein said policy manager is a customizable multi-thread scheduling unit outside the core of a processor; and

specify a dispatch scheduler within said core of said processor to be responsive to said policy manager to operate in accordance with said power performance metric;

wherein said executable instructions to define a policy manager include executable instructions to specify a low power virtual thread responsive to said power performance metric, and wherein said executable instructions to specify a dispatch scheduler include executable instructions to specify a dispatch scheduler to schedule said low power virtual thread but never select said low power virtual thread.

18. The computer readable storage medium of claim 17 wherein said executable instructions to define a policy manager include executable instructions to define a policy manager that tracks the operation of said low power virtual thread.

19. The computer readable storage medium of claim 17 wherein said executable instructions to specify a dispatch scheduler include executable instructions to specify a dispatch scheduler that specifies that no operations are performed in pipeline positions corresponding to pipeline positions of said low power virtual thread.

20. A method of enabling a computer to generate a processor, comprising:

selecting executable instructions that

define a policy manager responsive to a power performance metric from a software control module, wherein the policy manager is a customizable multi-thread scheduling unit outside the core of said processor; and

specify a dispatch scheduler responsive to said policy manager to operate a processor in accordance with said power performance metric, wherein said dispatch scheduler is within the core of said processor; and

transmitting said executable instructions over a network to a designated computer;

wherein selecting executable instructions includes selecting executable instructions that define a policy manager that specifies a low power virtual thread responsive to said power performance metric, and wherein selecting executable instructions includes selecting executable instructions that specify a dispatch scheduler to schedule said low power virtual thread but never select said low power virtual thread.

21. The method of claim 20 wherein selecting executable instructions includes selecting executable instructions to define a policy manager that tracks the operation of said low power virtual thread.

22. The method of claim 20 wherein selecting executable instructions includes selecting executable instructions to specify a dispatch scheduler that specifies that no operations are performed in pipeline positions corresponding to pipeline positions of said low power virtual thread.