Apparatus and method for dynamic central processing unit clock adjustment

• US 5,774,704 A
• Filed: 07/30/1996
• Issued: 06/30/1998
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Silicon Graphics Incorporated (Graphics Properties Holdings, Inc.)
• Inventors: Williams, Ian Michael
• Primary Examiner(s): Heckler, Thomas M.
• Application Number:
  US08/688,501
• Time in Patent Office: 700 Days
• Field of Search: 395/556
• US Class Current: 713/501
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In a computer system having a cpu, a device for dynamic cpu clock adjustment. The device is comprised of a clock pulse generator for generating a clock frequency. The clock frequency is coupled to the cpu and is used by the cpu to synchronize and pace its internal operations. The clock frequency generated by the generator is variable over a range. A controller is coupled to the clock pulse generator, for adjusting the clock frequency from the clock pulse generator over the range. The controller interfaces with the computer system through an interface coupled to the controller. Through the interface, the controller communicates with the computer system or cpu and determines a load placed on the cpu. The controller adjusts the clock frequency generated by the clock pulse generator such that the clock frequency increases when the load on the cpu increases and the clock frequency decreases when the load on the cpu decreases, dynamically adjusting the clock frequency in response to the load on the cpu.

Claims

1. In a computer system having a central processing unit (cpu), a cpu clock adjustment device, comprising:

a clock pulse generator coupled to the cpu for generating a clock frequency, wherein the clock frequency is variable over a range;

a controller coupled to the clock pulse generator for adjusting the clock frequency from the clock pulse generator over the range;

an interface coupled to the controller, the interface adapted to detect a load on the cpu, the interface for communicating the load on the cpu to the controller, such that the controller adjusts the clock frequency of the clock pulse generator in response to the load on the cpu; and

a cooling device coupled to the controller for delivering an amount of cooling to the cpu, the amount of cooling dynamically adjusted depending upon the load placed on the cpu.

2. The clock adjustment device of claim 1 wherein the clock frequency from the clock pulse generator is dynamically adjusted by the controller depending upon the load placed on the cpu by a software program or a portion of a software program.

3. The clock adjustment device of claim 2 wherein the clock frequency coupled to the cpu is reduced when the load placed on the cpu by the software program is reduced and the clock frequency coupled to the cpu is increased when the load placed on the cpu is increased.

4. The clock adjustment device of claim 1, wherein the controller is adapted to dynamically control the cooling device to deliver the amount of cooling to the cpu.

5. The clock adjustment device of claim 4 wherein the amount of cooling delivered to the cpu is adjusted depending upon a load placed on the cpu, the amount of cooling increased when the load placed on the cpu increases.

6. The clock adjustment device of claim 1 wherein the controller adjusts the clock frequency coupled to a plurality of cpu'"'"'s in response to a load on the plurality of cpu'"'"'s.

7. The clock adjustment device of claim 6 wherein the controller adjusts the clock frequency coupled to the plurality of cpu'"'"'s on either an individual basis, or, a collective basis.

8. The clock adjustment device of claim 1 further comprising a temperature sensor coupled to the controller, the temperature sensor coupled to the cpu, for sending a temperature of the cpu to the controller, wherein the controller adjusts the clock frequency depending upon the temperature of the cpu.

9. In a microprocessor based computer system for running software, a central processing unit (cpu) clock adjustment device, comprising:

a clock pulse generator coupled to the cpu for generating a clock frequency, wherein the clock frequency is variable over a range;

a controller coupled to the clock pulse generator for adjusting the clock frequency from the clock pulse generator over the range, the controller adapted to detect a load on the cpu, wherein the controller adjusts the clock frequency of the clock pulse generator in response to the load on the cpu;

a temperature sensor coupled to the controller for sending a temperature of the cpu to the controller, wherein the controller adjusts the clock frequency depending upon th e temperature of the cpu; and

a cooling device coupled to the controller for delivering an amount of cooling to the cpu, the amount of cooling dynamically adjusted depending upon the load placed on the cpu.

10. The clock adjustment device of claim 9 wherein the clock frequency from the clock pulse generator is dynamically adjusted by the controller depending upon the load placed on the cpu by software.

11. The clock adjustment device of claim 10 wherein the clock frequency coupled to the cpu is reduced when the load placed on the cpu by the software is reduced and the clock frequency coupled to the cpu is increased when the load placed on the cpu is increased.

12. The clock adjustment device of claim 9 wherein the controller is adapted to dynamically control the cooling device to deliver the amount of cooling.

13. The clock adjustment device of claim 12 wherein the amount of cooling delivered to the cpu is adjusted depending upon a load placed on the cpu, the amount of cooling increased when the load placed on the cpu increases.

14. The clock adjustment device of claim 9 wherein the controller adjusts the clock frequency coupled to a plurality of cpu'"'"'s in response to a load on the plurality of cpu'"'"'s.

15. The clock adjustment device of claim 14 wherein the controller adjusts the clock frequency coupled to the plurality of cpu'"'"'s on either an individual basis, or, a collective basis.

16. In a computer system having a central processing unit (cpu), a method for adjusting a clock frequency coupled to the cpu, comprising the steps of:

generating the clock frequency, wherein the clock frequency is used by the cpu to synchronize internal operations of the cpu;

detecting a load on the cpu, wherein the load originates from software executing on the cpu;

increasing the clock frequency when the load placed on the cpu exceeds a threshold;

decreasing the clock frequency when the load placed on the cpu does not exceed the threshold, such that the clock frequency is dynamically adjusted in response to the load placed on the cpu by software;

setting an amount of cooling delivered to the cpu;

increasing the amount of cooling delivered to the cpu when the load placed on the cpu by software exceeds the threshold;

decreasing the amount of cooling delivered to the cpu when the load placed on the cpu by software does not exceed the threshold, such that the amount of cooling is dynamically adjusted in response to the load placed on the cpu.

17. The method of claim 16, further comprising the steps of:

determining whether an over temperature condition exists in the cpu;

decreasing the clock frequency if there is an over temperature condition in the cpu.

18. The method of claim 16, further comprising the steps of:

setting an amount of cooling delivered to the cpu;

increasing the amount of cooling delivered to the cpu when the load placed on the cpu by software exceeds the threshold;

decreasing the amount of cooling delivered to the cpu when the load placed on the cpu by software does not exceed the threshold, such that the amount of cooling is dynamically adjusted in response to the load placed on the cpu.

19. The method of claim 18, further comprising the steps of:

determining whether an over temperature condition exists in the cpu;

increasing the amount of cooling if there is an over temperature condition in the cpu.

20. In a computer system having a microprocessor, a microprocessor clock adjustment device, comprising:

a clock pulse generator coupled to the microprocessor for generating a clock frequency, wherein the clock frequency is variable over a range;

a controller coupled to the clock pulse generator for adjusting the clock frequency from the clock pulse generator over the range;

an interface coupled to the controller, the interface adapted to detect a load on the microprocessor, wherein the load is determined by monitoring a pipeline control within the microprocessor, the interface for communicating the load on the microprocessor to the controller, such that the controller adjusts the clock frequency of the clock pulse generator in response to the load on the microprocessor.

21. The clock adjustment device of claim 20 wherein the pipeline control is coupled to a floating point unit, a memory management unit, and a central processing unit to coordinate the operation of the microprocessor, the load determined by monitoring the activity of the pipeline control.

22. The clock adjustment device of claim 20 wherein the clock frequency from the clock pulse generator is dynamically adjusted by the controller depending upon the load placed on the microprocessor by a software program or a portion of a software program.

23. The clock adjustment device of claim 22 wherein the clock frequency coupled to the microprocessor is reduced when the load placed on the microprocessor by the software program is reduced and the clock frequency coupled to the microprocessor is increased when the load placed on the microprocessor is increased.

24. The clock adjustment device of claim 20 further comprising a cooling device coupled to the controller for delivering an amount of cooling to the microprocessor, the amount of cooling dynamically adjusted depending upon the load placed on the microprocessor.

25. The clock adjustment device of claim 24 wherein the amount of cooling delivered to the microprocessor is adjusted depending upon a load placed on the microprocessor, the amount of cooling increased when the load placed on the microprocessor increases.

26. The clock adjustment device of claim 20 wherein the controller adjusts the clock frequency coupled to a plurality of microprocessor'"'"'s in response to a load on the plurality of microprocessor'"'"'s.

27. The clock adjustment device of claim 26 wherein the controller adjusts the clock frequency coupled to the plurality of microprocessor'"'"'s on either an individual basis, or, a collective basis.

28. The clock adjustment device of claim 20 further comprising a temperature sensor coupled to the controller, the temperature sensor coupled to the microprocessor, for sending a temperature of the microprocessor to the controller, wherein the controller adjusts the clock frequency depending upon the temperature of the microprocessor.