Conserving energy in a data processing system by selectively powering down processors

• US 20030115495A1
• Filed: 12/13/2001
• Published: 06/19/2003
• Est. Priority Date: 12/13/2001
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Rawson, Freeman Leigh III
• Granted Patent: US 7,318,164 B2
• Time in Patent Office: Days
• US Class Current: 713/324
• CPC Class Codes: G06F 1/3228 Monitoring task completion, e.g. by use of idle timers, stop commands or wait commands
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: G06F 9/5061 Partitioning or combining of resources
• CPC Class Codes: G06F 9/5094 where the allocation takes into account power or heat criteria power management in computers in general G06F1/3203; thermal management in computers in general G06F1/206
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A system and method for selectively activating and deactivating processors in a multi-processor system environment in response to variations in the demand for CPU processing power presented to the system. During periods of reduced processing activity, the system may select one or more of its processors for deactivation. If the processing activity subsequently increases, the number of processors may be increased to insure that a minimum specified performance or response requirement is achieved. The system may include or employ various hardware facilities and/or software modules to monitor the system'"'"'s workload, typically measured in terms of the demand for CPU cycles. The system may include a policy manager that receives workload information from the workload module and determines the required number of processors based on a predetermined performance criteria. In addition, the system may include a resource pool module that determines which processors are to be activated and deactivated in response to changes in the required number of processors as determined by the policy manager. The resource pool module may be further responsible for preparing a selected processor for deactivation by migrating any processes or thread running on the selected processor to other processor(s) in the pool of available processors and by flushing the contents of the selected processor'"'"'s cache memory. The system may further include a CPU power control module that is configured to transition a processor selected for deactivation from a full power state to a low-power state.

Claims

1. A method of conserving power consumption in a multi-processor data processing system, comprising:

monitoring a workload of the system;

determining a number of processors required to process the monitored workload at a predetermined performance criterion;

activating or deactivating processors to conform the number of active processors in the system to the determined number of processors; and

processing the workload with the active processors while maintaining the deactivated processors in a reduced power state.

2. The method of claim 1, wherein determining the number of processors required comprises determining the minimum number of processors required to achieve the performance criterion.

3. The method of claim 1, wherein deactivating a processor includes selecting a processor for deactivation based on the processor'"'"'s workload.

4. The method of claim 1, wherein deactivating a processor includes migrating processes pending on a processor selected for deactivation to another processor.

5. The method of claim 4, wherein deactivating a processor further includes flushing the processor'"'"'s cache memory before deactivating the processor.

6. The method of claim 1, wherein deactivating a processor comprises transitioning a processor to the lowest power state supported by the processor.

7. The method of claim 1, wherein monitoring the workload comprises determining the demand for CPU cycles.

8. The method of claim 7, wherein monitoring the workload includes determining the instantaneous workload periodically and averaging the instantaneous workload data to obtain an average workload.

9. A data processing system including processor, memory, and I/O means, the system including a sequence of processor executable instructions for conserving power, the instructions being stored on a computer readable medium, comprising:

computer code means for monitoring a workload of the system;

computer code means for determining a number of processors required to process the monitored workload at a predetermined performance criterion;

computer code means for activating or deactivating processors to conform the number of active processors in the system to the determined number of processors; and

computer code means for processing the workload with the active processors while maintaining the deactivated processors in a reduced power state.

10. The system of claim 9, wherein the code means for determining the number of processors required comprises code means for determining the minimum number of processors required to achieve the performance criterion.

11. The system of claim 9, wherein the code means for deactivating a processor includes code means for selecting a processor for deactivation based on the processor'"'"'s workload.

12. The system of claim 9, wherein the code means for deactivating a processor includes code means for migrating processes pending on a processor selected for deactivation to another processor.

13. The system of claim 12, wherein the code means for deactivating a processor further includes code means for flushing the processor'"'"'s cache memory before deactivating the processor.

14. The system of claim 9, wherein the code means for deactivating a processor comprises code means for transitioning a processor to the lowest power state supported by the processor.

15. The system of claim 9, wherein the code means for monitoring the workload comprises code means for determining the demand for CPU cycles.

16. The system of claim 15, wherein the code means for monitoring the workload includes code means for determining the instantaneous workload periodically and averaging the instantaneous workload data to obtain an average workload.

17. A computer program product comprising a sequence of processor executable instructions for conserving power, the instructions being stored on a computer readable medium, comprising:

computer code means for monitoring a workload of the system;

computer code means for determining a number of processors required to process the monitored workload at a predetermined performance criterion;

computer code means for activating or deactivating processors to conform the number of active processors in the system to the determined number of processors; and

computer code means for processing the workload with the active processors while maintaining the deactivated processors in a reduced power state.

18. The computer program product of claim 17, wherein the code means for determining the number of processors required comprises code means for determining the minimum number of processors required to achieve the performance criterion.

19. The computer program product of claim 17, wherein the code means for deactivating a processor includes code means for selecting a processor for deactivation based on the processor'"'"'s workload.

20. The computer program product of claim 17, wherein the code means for deactivating a processor includes code means for migrating processes pending on a processor selected for deactivation to another processor.

21. The computer program product of claim 20, wherein the code means for deactivating a processor further includes code means for flushing the processor'"'"'s cache memory before deactivating the processor.

22. The computer program product of claim 17, wherein the code means for deactivating a processor comprises code means for transitioning a processor to the lowest power state supported by the processor.

23. The computer program product of claim 17, wherein the code means for monitoring the workload comprises code means for determining the demand for CPU cycles.

24. The computer program product of claim 23, wherein the code means for monitoring the workload includes code means for determining the instantaneous workload periodically and averaging the instantaneous workload data to obtain an average workload.