Method and apparatus for controlling operating speed of processor in computer

• US 6,513,124 B1
• Filed: 05/14/1999
• Issued: 01/28/2003
• Est. Priority Date: 05/20/1998
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shimotono, Susumu, Furuichi, Sanehiro, Aihara, Toru
• Primary Examiner(s): BUTLER, DENNIS
• Application Number:
  US09/311,926
• Time in Patent Office: 1,355 Days
• Field of Search: 713/300, 713/320, 713/322, 713/500, 713/501, 713/502, 713/600, 713/601
• US Class Current: 713/322
• 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 1/324 by lowering clock frequency
• CPC Class Codes: G06F 11/3409 for performance assessment
• CPC Class Codes: G06F 2201/81 Threshold
• CPC Class Codes: G06F 2201/88 Monitoring involving counting
• CPC Class Codes: G06F 9/30083 Power or thermal control instructions
• CPC Class Codes: G06F 9/3836 Instruction issuing, e.g. dynamic instruction scheduling or out of order instruction execution
• CPC Class Codes: G06F 9/3869 Implementation aspects, e.g. pipeline latches; pipeline synchronisation and clocking
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

The number of executed instructions (I_u) in a user mode as one of performance indexes of a computer, and the total number of executed instructions (I_t) as one of power consumption indexes are used. These parameters have a relationship of E−I_t/I_u with energy index E. An operating speed (operating frequency) of CPU is increased or decreased so that a value of the performance index may be increased within a range of the power consumption index specified by a user, or a value of the energy index E may be decreased. By doing so, power management processing may be performed, which balances the power saving with the performance.

Claims

1. A method for controlling operating speed of a processor in a computer, comprising the steps of:

counting the number of executed instructions (I_u) in a user mode during a first predetermined period; and

changing the operating speed of said processor based on said I_u.

2. The method according to claim 1, further comprising the steps of:

recounting I_u after execution of said changing step; and

performing said changing step again.

3. The method according to claim 1, further comprising the steps of:

counting the number of executed instructions (I_u2) in a user mode during a second predetermined period; and

if the rate of change from said I_u to said I_u2 is higher than a predetermined value, setting the operating speed of said processor to the predetermined value.

4. The method according to claim 1, further comprising a step of counting the total number of executed instructions (I_t) during a second predetermined period.

5. The method according to claim 4, further comprising a step of changing the operating speed of said processor by referring to said I_t.

6. The method according to claim 4, wherein said first predetermined period and said second predetermined period are the same.

7. The method according to claim 6, wherein said changing step includes a step of switching a change control mode of the operating speed by referring to a ratio of said I_t and I_u.

8. The method according to claim 6, wherein said changing step includes a steps of switching the change control flow of the operating speed by referring to a ratio of said I_t and I_u.

9. The method according to claim 6, further comprising a step of, after performing said changing step, changing the operating frequency of said processor by recounting said I_t and I_u and referring to a ratio of said I_t and I_u.

10. A method for controlling operating speed of a processor in a computer, comprising the steps of:

counting the number of executed instructions (I_u) in a user mode during a predetermined period;

counting the total number of executed instructions (I_t) during said predetermined period;

by referring to a ratio of said I_t and I_u, switching a policy for changing the operating speed; and

by referring to said policy, changing the operating speed of said processor.

11. A method for controlling operating speed of a processor in a computer, comprising the steps of:

measuring a value of a first performance index during a first predetermined period;

changing the operating speed of said processor;

measuring a value of a second performance index during a second predetermined period; and

by referring to measured values of said first and second performance indexes, changing the operating speed of said processor.

12. The method according to claim 11, further comprising the steps of:

measuring a value of a power consumption index during a third predetermined period; and

based on the value of said power consumption index, changing the operating speed of said processor.

13. The method according to claim 11, wherein each of said changing steps comprises changing the operating speed of said processor so that the performance is increased.

14. A method for controlling operating speed of a processor in a computer, comprising the steps of:

measuring values of a performance index and a power consumption index;

by referring to a ratio of the measured values of said performance index and said power consumption index, changing a policy for changing the operating speed of said processor; and

by referring to said policy, changing the operating speed of said processor.

15. A method for controlling an operating speed of a processor in a computer, comprising the steps of:

measuring values of a performance index and a power consumption index;

calculating a value of an energy index from the measured value of said performance index and said power consumption index; and

changing the operating speed of said processor so as to decrease the value of said energy index.

16. A computer comprising:

a first counter for counting the number of instructions (I_u) in a user mode executed by a processor during a predetermined period; and

a controller for changing the operating speed of said processor by referring to said I_u.

17. The computer according to claim 16, further comprising a second counter for counting the total number of instructions (I_t) executed by said processor during said predetermined period, wherein said controller changes the operating speed of said processor by referring to a ratio of said I_u and I_t.

18. A computer comprising:

a measuring device for measuring a value of a performance index of said computer; and

a controller for changing an operating speed of a processor in said computer,

wherein said measuring device measures a value of a first performance index during a first predetermined period, and said controller thereafter changes the operating speed of said processor, and after the change of said operating speed, said measuring device measures a value of a second performance index during a second predetermined period, and said controller changes operating speed of said processor by referring to measured values of said first and second performance indexes.

19. The computer according to claim 18, wherein said controller changes the operating speed of said processor so as to increase the performance by referring to values of said first and second performance indexes.

20. A computer comprising:

a first measuring device for measuring a value of a performance index of said computer;

a second measuring device for measuring a value of a power consumption index of said computer; and

a controller for changing the operating speed of said processor by referring to a ratio of the measured values of said performance index and said power consumption index.

21. A computer comprising:

a first measuring device for measuring a value of a performance index of said computer;

a second measuring device for measuring a value of a power consumption index of said computer; and

a controller for calculating a value of an energy index from the measured values of said performance index and said power consumption index and changing the operating speed of said processor so as to decrease the value of said energy index.

22. A storage medium for storing a program for causing a processor in a computer to change its operating speed, said program comprising the steps of:

reading out a count of the number of executed instructions (I_u) in a user mode during a predetermined period; and

by referring to said I_u, setting the operating speed of said processor.

23. The storage medium according to claim 22, said program further comprising a step of reading out a count of the total number of executed instructions (I_t) during said predetermined period, wherein said setting step includes a step of switching a control flow of said operating speed by referring to a ratio of said I_t and I_u.

24. A storage medium for storing a program for causing a processor in a computer to change its operating speed, said program comprising the steps of:

reading out a count of the number of executed instructions (I_u) in a user mode during a predetermined period;

reading out a count of the total number of executed instructions (I_t) during said predetermined period; and

by referring to a ratio of said I_t and I_u, setting the operating speed of said processor.

25. A storage medium for storing a program for causing a processor in a computer to change an operating speed of said processor, said program comprising the steps of:

reading out measurement result of a first performance index during a first predetermined period;

instructing a change of the operating speed of said processor;

reading out the measurement result of a second performance index during a second predetermined period; and

by referring to measured values of said first and second performance indexes, setting the operating speed of said processor.

26. A storage medium for storing a program for causing a processor in a computer to change an operating speed of said processor, said program comprising the steps of:

reading out measurement results of a performance index and a power consumption index; and

by referring to a ratio of the measured values of said performance index and said power consumption index, setting the operating speed of said processor.

27. A storage medium for storing a program for causing a processor in a computer to change an operating speed of said processor, said program comprising the steps of:

reading out measurement results of a performance index and a power consumption index;

calculating a value of an energy index from the measured values of said performance index and said power consumption index; and

setting the operating speed of said processor so as to decrease the value of said energy index.