Method and system for dynamically adjusting DRAM refresh rate

• US 20060085616A1
• Filed: 10/20/2004
• Published: 04/20/2006
• Est. Priority Date: 10/20/2004
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Johnson, Brian M., Zeighami, Roy Mehdi, Soper, David Russel, Wastlick, John M.
• Granted Patent: US 7,305,518 B2
• Time in Patent Office: Days
• US Class Current: 711/167
• CPC Class Codes: G06F 13/1689 Synchronisation and timing concerns synchronisation on a memory bus G06F13/4234
• CPC Class Codes: G11C 11/406 Management or control of the refreshing or charge-regeneration cycles
• CPC Class Codes: G11C 11/40611 External triggering or timing of internal or partially internal refresh operations, e.g. auto-refresh or CAS-before-RAS triggered refresh
• CPC Class Codes: G11C 2211/4061 Calibration or ate or cycle tuning
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

One embodiment is a method of dynamically adjusting a rate at which a dynamic random access memory (“DRAM”) module is refreshed in a computer system. The method comprises monitoring a plurality of system conditions; detecting a change in at least one of the monitored system conditions; responsive to the detection, determining an optimum refresh rate for a current state of the computer system; and setting the refresh rate to the determined optimum refresh rate.

Claims

1. A method of dynamically adjusting a rate at which a dynamic random access memory (“

DRAM”

) module is refreshed in a computer system, the method comprising;

monitoring a plurality of system conditions;

detecting a change in at least one of the monitored system conditions;

responsive to the detection, determining an optimum refresh rate for a current state of the computer system; and

setting the refresh rate to the determined optimum refresh rate.

2. The method of claim 1 wherein the monitored system conditions are selected from a group of system conditions consisting of temperature, power consumption, altitude, air pressure, DRAM manufacturer, memory module loading locations, and bus utilization.

3. The method of claim 1 wherein the monitoring is performed using a thermal sensing element.

4. The method of claim 1 wherein the monitoring is performed using a performance counter.

5. The method of claim 1 wherein the monitoring is performed using an altimeter.

6. The method of claim 1 wherein the monitoring is performed using a barometer.

7. The method of claim 1 wherein the detecting comprises detecting failure of a cooling fan associated with the computer system.

8. The method of claim 7 wherein the determined optimum refresh rate is higher than an original refresh rate.

9. The method of claim 1 wherein the detecting comprises detecting repair of a cooling fan associated with the computer system.

10. The method of claim 9 wherein the determined optimum refresh rate is lower than an original refresh rate.

11. The method of claim 1 wherein the determining comprises obtaining an optimum refresh rate corresponding to the at least one system condition in a look-up table.

12. The method of claim 1 wherein the determining comprises applying a formula to the at least one system condition, wherein a result of the applying comprises an optimum refresh rate corresponding to the at least one system condition.

13. The method of claim 1 wherein the setting comprises sending a Set Refresh Rate (“

SRR”

) signal to a chipset connected to the DRAM module to set a rate at which Refresh commands are sent to the DRAM module.

14. A system for dynamically adjusting a rate at which a dynamic random access memory (“

DRAM”

) module is refreshed in a computer system, the system comprising;

means for monitoring a plurality of system conditions;

means for detecting a change in at least one of the monitored system conditions;

means responsive to detection of a change in at least one of the monitored system conditions for determining an optimum refresh rate for a current state of the computer system; and

means for setting the refresh rate to the determined optimum refresh rate.

15. The system of claim 14 wherein the monitored system conditions are selected from a group of system conditions consisting of temperature, power consumption, altitude, air pressure, DRAM manufacturer, memory module loading locations, and bus utilization.

16. The system of claim 14 wherein the means for monitoring comprises a measurement device selected from a group consisting of a thermal sensing element, a performance counter, an altimeter, and a barometer.

17. The system of claim 15 wherein the means for detecting comprises means for detecting failure of a cooling fan associated with the computer system.

18. The system of claim 17 wherein the determined optimum refresh rate is higher than an original refresh rate.

19. The system of claim 14 wherein the means for detecting comprises means for detecting repair of a cooling fan associated with the computer system.

20. The system of claim 19 wherein the determined optimum refresh rate is lower than an original refresh rate.

21. The system of claim 14 wherein the means for determining comprises a multi-dimensional look-up table wherein a current state of the computer system maps to a corresponding optimum refresh rate.

22. The system of claim 14 wherein the means for determining comprises means for applying a formula to the at least one system condition to calculate an optimum refresh rate corresponding to the at least one system condition.

23. The system of claim 14 wherein the means for setting comprises:

system firmware for issuing a Set Refresh Rate (“

SRR”

) signal to set a rate at which Refresh commands are sent to the DRAM module; and

a chipset responsive to the SRR signal for issuing Refresh commands to the DRAM module.

24. The system of claim 23 wherein the chipset comprises a cell controller connected to the DRAM module.

25. The system of claim 14 wherein the means for detecting comprises manageability firmware.

26. A computer-readable medium operable with a computer system dynamically adjusting a rate at which a dynamic random access memory (“

DRAM”

) module is refreshed in the computer system, the medium having stored thereon;

instructions executable by the computer system for causing a plurality of system conditions to be monitored;

instructions executable by the computer system for detecting a change in at least one monitored system condition;

instructions executable by the computer system responsive to detection of a change in at least one monitored system condition for determining an optimum refresh rate for a current state of the computer system; and

instructions executable by the computer system for setting the refresh rate to the determined optimum refresh rate.

27. The computer-readable medium of claim 26 wherein the at least one monitored system condition is selected from a group of system conditions consisting of temperature, power consumption, altitude, air pressure, DRAM manufacturer, memory module loading locations, and bus utilization.

28. The computer-readable medium of claim 26 wherein the instructions executable by the computer system for detecting comprise instructions for detecting failure of a cooling fan associated with the computer system.

29. The computer-readable medium of claim 28 wherein the determined optimum refresh rate is higher than an original refresh rate.

30. The computer-readable medium of claim 26 wherein the instructions executable by the computer system for detecting comprise instructions for detecting reinstatement of a cooling fan associated with the computer system.

31. The computer-readable medium of claim 30 wherein the determined optimum refresh rate is lower than an original refresh rate.

32. The computer-readable medium of claim 26 wherein the instructions executable by the computer system for determining comprise instructions for obtaining an optimum refresh rate corresponding to the at least one system condition in a look-up table.

33. The computer-readable medium of claim 26 wherein the instructions executable by the computer system for determining comprise instructions for applying a formula to the at least one system condition, wherein a result of the applying comprises an optimum refresh rate corresponding to the at least one system condition.

34. The computer-readable medium of claim 26 wherein the instructions executable by the computer system for setting comprise instructions for sending a Set Refresh Rate (“

SRR”

) signal to a chipset to set a rate at which Refresh commands are sent to the DRAM module.