Progressive CPU sleep state duty cycle to limit peak power of multiple computers on shared power distribution unit

• US 6,904,534 B2
• Filed: 09/29/2001
• Issued: 06/07/2005
• Est. Priority Date: 09/29/2001
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Koenen, David J.
• Primary Examiner(s): Browne, Lynne H.
• Assistant Examiner(s): Patel, Nitin C.
• Application Number:
  US09/968,416
• Publication Number:
  US 20030065961A1
• Time in Patent Office: 1,347 Days
• Field of Search: 713/300, 713/310, 713/320, 713/322, 713/323, 713/340, 713/324
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode

Abstract

A method and apparatus for distributing power to a plurality of computers in a network. A power management system including a feed-back mechanism, is employed to monitor power consumptions of the plurality of computers. Should the overall power consumption reach a threshold, the power management system instructs the microprocessors in the plurality of computers to enter into a lower power state, such as a sleep state, for a certain duration, thus lowering overall power.

Claims

1. A computer system, comprising:

a power management system; and

a plurality of computers, including a plurality of microprocessors, the plurality of computers coupled to the power management system;

the power management system to monitor a plurality of current demands of the computers, and

the power management system to instruct the plurality of microprocessors to enter into a certain lower power state for a certain duration responsive to changing current demands of the plurality of computers,

wherein the certain duration is a power down duty cycle.

2. The computer system of claim 1, wherein the microprocessor is a Pentium-type processor.

3. The computer system of claim 2, wherein the lower power state is a sleep state.

4. The computer system of claim 3, wherein the plurality of microprocessors can respond to snoops and interrupts in the sleep state.

5. The computer system of claim 3, wherein the sleep state is a stop-grant state.

6. The computer system of claim 1, wherein the power management system instructs the plurality of microprocessors to enter into a certain lower power state for certain duration by a command encoded in power lines from the power management system to the plurality of computers.

7. The computer system of claim 1, wherein the power management system instructs the plurality of microprocessors to enter into a certain lower power state for certain duration by a command over a data link.

8. The computer system of claim 1, wherein the power management system is not included in one of the plurality of computers.

9. The computer system of claim 1, wherein the power management system is included in one of the plurality of computers.

10. The computer system of claim 1, wherein the changing current demands is a cumulative current demand of the plurality of computers.

11. A computer system, comprising:

a power management system; and

a plurality of computers, including a plurality of microprocessors, the plurality of computers coupled to the power management system;

the power management system to monitor a plurality of current demands of the computers, and

the power management system to instruct the plurality of microprocessors to enter into a certain lower power state for a certain duration responsive to changing current demands of the plurality of computers,

wherein the plurality of computers include a plurality of monitors for measuring the plurality of current demands.

12. A method for providing power to a plurality of computers, comprising the steps of:

measuring current demands for the plurality of computers;

calculating a total current demand; and

placing each computer in a lower power state for a selected percentage of time in response to the total current demand exceeding a threshold,

wherein the selected percentage of time varies according to a predefined relationship with respect to the total current demand.

13. The method of claim 12, wherein the plurality of computers include Pentium-type microprocessors.

14. The method of claim 12, wherein the lower power state is a sleep state.

15. The method of claim 14, further comprising the step of responding to snoops and interrupts while each computer is in the sleep state.

16. The method of claim 15, wherein the sleep state is a stop-grant state.

17. The method of claim 12, wherein the predefined relationship is a linear relationship between the selected percentage of time and the total current demand over a range of the total current demand.

18. A method for providing power to a plurality of computers, comprising the steps of:

measuring current demands for the plurality of computers;

calculating a total current demand; and

placing each computer in a lower power state for a certain time should the total current demand exceed a threshold,

wherein placing each computer in a sleep state includes asserting a STPCLK signal.

19. A method for providing power to a plurality of computers, comprising the steps of:

measuring current demands for the plurality of computers;

calculating a total current demand; and

placing each computer in a lower power state for a certain time should the total current demand exceed a threshold,

wherein the certain time is a power down duty cycle.

20. The method of claim 19, wherein the power down duty cycle is less than 90%.

21. A method of managing power in a system having plural computers, comprising:

measuring, with current monitors in respective plural computers, a local current demand of each computer;

calculating a total current demand based on the measured local current demands of the computers; and

placing each computer into a lower power state for a selected time period in response to detecting that the total current demand exceeds a threshold.

22. A system comprising:

a power management controller; and

a plurality of computers coupled to the power management controller,

the power management controller to receive measured local current demands from the computers and to calculate a total current demand based on the measured local current demands,

the power management controller to further place each computer in a lower power state for a selected percentage of time in response to the total current demand exceeding a threshold,

wherein the selected percentage of time varies according to a predefined relationship with respect to the total current demand.

23. The system of claim 22, wherein the predefined relationship is a linear relationship between the selected percentage of time and the total current demand over a range of the total current demand.