Power aware adaptive polling

• US 7,093,141 B2
• Filed: 12/18/2002
• Issued: 08/15/2006
• Est. Priority Date: 12/18/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Elnozahy, Elmootazbellah N., Van Hensbergen, Eric
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): SURYAWANSHI, SURESH
• Application Number:
  US10/324,738
• Publication Number:
  US 20040123169A1
• Time in Patent Office: 1,336 Days
• Field of Search: 713/300, 713/310, 713/320, 713/324, 713/185, 713/323, 370/318, 710/15, 710/46
• US Class Current: 713/300
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections

Abstract

A method for adapting the periodicity of polling for pending service requests, by polling system devices for pending service requests, recording whether or not there was a pending service request and, based on accumulated data, determining whether or not the system devices are idle. Based on this determination, the system may elect to enter a power conservation mode until device activity is signaled, or an adjustable period of time elapses. The adaptation mechanism may alter the periodicity of the timer interrupt, disable or enable device interrupts, and modify variables used to determine system idleness (including minimum latency and minimum idleness thresholds). In this manner, the system can conserve power while maintaining system performance and responsiveness.

Claims

1. A method for adapting the periodicity of polling for pending device service requests in a data processing system having a system processor and one or more input/output (I/O) devices, comprising the steps of:

polling the I/O devices of the data processing system for pending service requests;

recording whether there was a pending service request;

adaptively adjusting one or more system polling variables when there is no pending service request from at least one of the I/O devices;

based on accumulated data, determining that the I/O devices are idle; and

in response to said determining step, placing the system processor in a low power state.

2. The method of claim 1, further comprising the step of handling one or more service requests received from said polling step.

3. The method of claim 1, wherein said adjusting adaptively sets a threshold of a minimum number of polls which do not find pending service requests before a device is considered idle.

4. The method of claim 1, wherein said adjusting adaptively sets a period of a timer quanta corresponding to how often the system processor is interrupted by a timer, in response to system and device inactivity.

5. The method of claim 1, further comprising the steps of enabling and disabling device interrupts in response to device activity and the lack thereof.

6. The method of claim 1, wherein said adjusting adaptively sets a minimum latency threshold for a maximum amount of time the system processor may stay in the low power state while there may be pending service requests.

7. The method of claim 1, further comprising the step of resuming operation of the system processor after it is placed in the low power state in response to a later interrupt.

8. A data processing system comprising:

at least one system processor;

a memory device connected to said system processor;

one or more input/output (I/O) devices connected to said system processor; and

program instructions stored in said memory device for adapting the periodicity of polling for pending service requests, by polling said I/O devices for pending service requests, recording whether there was a pending service request, adaptively adjusting one or more system polling variables when there in no pending service request from at least one of the I/O devices, based on accumulated data determining that the I/O devices are idle, and responsively placing said system processor in a low power state.

9. The data processing system of claim 8 wherein said program

instructions further handle one or more interrupts received from the polling.

10. The data processing system of claim 8 wherein said adjusting adaptively sets a threshold of a minimum number of polls which do not find pending service requests before a device is considered idle.

11. The data processing system of claim 8 wherein said adjusting adaptively sets a period of a timer quanta corresponding to how often said system processor is interrupted by a timer, in response to system and device inactivity.

12. The data processing system of claim 8 wherein said program instructions further enable and disable device interrupts in response to device activity and the lack thereof.

13. The data processing system of claim 8 wherein said adjusting adaptively sets a minimum latency threshold for a maximum amount of time the system processor may stay in the low power state while there may be pending service requests.

14. The data processing system of claim 8 wherein said program instructions resume operation of said system processor after it is placed in the low power state in response to a later interrupt.

15. A computer program product executed in a data processing system for adapting the periodicity of polling for pending device service requests,the data processing system having a system processor and one or more input/output (I/O) devices, comprising:

a computer-readable medium; and

program instruction residing in said medium for polling the I/O devices for pending service requests, recording whether there was a pending service request, adaptively adjusting one or more system polling variables where there is no pending request from at least one of the I/O devices, based on accumulated data determining that the I/O devices are idle, and responsively placing the system processor in a low power state.

16. The computer program product of claim 15 wherein said program instructions further handle one or more interrupts received from the polling.

17. The computer program product of claim 15 wherein said adjusting adaptively sets a threshold of a minimum number of polls which do not find pending service requests before a device is considered idle.

18. The computer program product of claim 15 wherein said adjusting adaptively sets a period of a timer quanta corresponding to how often the system processor is interrupted by a timer, in response to system and device inactivity.

19. The computer program product of claim. 15 wherein said program instructions further enable and disable device interrupts in response to device activity and the lack thereof.

20. The computer program product of claim 19 wherein said adjusting adaptively sets a minimum latency threshold for a maximum amount of time the system processor may stay in the low power state while there may be pending service requests.

21. The computer program product of claim 19 wherein said program instructions resume operation of the system processor after it is placed in the low power state in response to a later interrupt.