Method, system, and program for determining a number of write operations to execute

• US 6,732,193 B1
• Filed: 06/09/2000
• Issued: 05/04/2004
• Est. Priority Date: 06/09/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Burton, David Alan, Webman, Erez, Morton, Robert Louis
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): SCHNEIDER, JOSHUA D
• Application Number:
  US09/591,023
• Time in Patent Office: 1,425 Days
• Field of Search: 710/5, 710/6, 710/57, 709/234, 709/235, 709/233, 709/238, 711/161, 711/162
• US Class Current: 710/5
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Disclosed is a method, system, program, and data structure for executing write operations. A first number of write operations is initiated. Performance data is gathered indicating a total time for a second number of the initiated write operations to complete. After at least one initiated write operation has completed, at least one additional write operation is initiated if a number of outstanding write operations is less than a maximum number of write operations. The maximum number of write operations is adjusted if the performance data meets at least one threshold.

Claims

1. A method for executing write operations, comprising:

initiating a first number of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold.

2. The method of claim 1, wherein the second number is greater than or equal to the first number.

3. A method for executing write operations, comprising:

initiating a first number of write operations, wherein the write operations are part of a series of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold, wherein performance data is gathered and adjustments to the maximum number considered each time the second number of write operations are completed while there are further write operations in the series of write operations to perform.

4. A method for executing write operations, comprising:

initiating a first number of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations;

comparing the total time for the second number of write operations to complete with a previous best time for the second number of write operations to complete; and

adjusting the maximum number of write operations if the time for the write operations to complete meets at least one threshold with respect to the previous best time.

5. The method of claim 4, wherein adjusting the maximum number comprises adjusting the maximum number upward if the total time exceeds the previous best time by a percentage amount.

6. The method of claim 5, further comprising initiating at least one additional write operation when adjusting the maximum number upwards.

7. The method of claim 4, wherein adjusting the maximum number comprises adjusting the maximum number downward if the total time is less than the previous best time by a percentage amount.

8. The method of claim 4, further comprising:

setting the best time to the total time if the total time exceeds the best time, wherein the adjusted best time is used when determining whether to adjust the maximum number.

9. A method for executing write operations, comprising:

initiating a first number of write operations;

gathering, performance data indicating a total time for a second number of the initiated write operations to complete by;

(i) starting a timer for each initiated write operation when the write operation is initiated;

(ii) adding a time value of one timer to the total time after receiving acknowledgment that the write operation for the timer has completed; and

(iii) resetting the total time to zero after gathering the performance data for the second number of write operations

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold.

11. The method of claim 9, further comprising:

transferring, with the first controller, the initiated write operations to a second controller, wherein the second controller executes the write operations against the second storage device.

10. A method for executing write operations, comprising:

initiating a first number of write operations, wherein a controller initiates write operations to copy data from a first storage device to a second storage device;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold.

12. A system for executing write operations, comprising:

means for initiating a first number of write operations;

means for gathering performance data indicating a total time for a second number of the initiated write operations to complete;

means for initiating at least one additional write operation if, after at least one initiated write operation has completed, a number of outstanding write operations is less than a maximum number of write operations; and

means for adjusting the maximum number of write operations if the performance data meets at least one threshold.

13. The system of claim 12, wherein the second number is greater than or equal to the first number.

22. The system of claim 12, wherein the controller comprises a first controller, further comprising:

a second controller;

means for transferring the initiated write operations from the first controller to the second controller, wherein the second controller executes the write operations against the second storage device.

14. A system for executing write operations, comprising:

means for initiating a first number of write operations, wherein the write operations are part of a series of write operations;

means for gathering performance data indicating a total time for a second number of the initiated write operations to complete;

means for initiating at least one additional write operation if, after at least one initiated write operation has completed, a number of outstanding write operations is less than a maximum number of write operations; and

means for adjusting the maximum number of write operations if the performance data meets at least one threshold, wherein performance data is gathered and adjustments to the maximum number considered each time the second number of write operations are completed while there are further write operations in the series of write operations to perform.

15. A system for executing write operations, comprising:

means for initiating a first number of write operations;

means for gathering performance data indicating a total time for a second number of the initiated write operations to complete;

means for initiating at least one additional write operation if, after at least one initiated write operation has completed, a number of outstanding write operations is less than a maximum number of write operations;

means for comparing the total time for the second number of write operations to complete with a previous best time for the second number of write operations to complete; and

adjusting the maximum number of write operations if the time for the write operations to complete meets at least one threshold with respect to the previous best time.

16. The system of claim 15, wherein the means for adjusting the maximum number adjusts the maximum number upward if the total time exceeds the previous best time by a percentage amount.

17. The system of claim 16, further comprising means for initiating at least one additional write operation when adjusting the maximum number upwards.

18. The system of claim 15, wherein the means for adjusting the maximum number adjusts the maximum number downward if the total time is less than the previous best time by a percentage amount.

19. The system of claim 15, further comprising:

means for setting the best time to the total time if the total time exceeds the best time, wherein the adjusted best time is used when determining whether to adjust the maximum number.

20. A system for executing write operations, comprising:

means for initiating a first number of write operations;

means for gathering performance data indicating a total time for a second number of the initiated write operations to complete by;

(i) starting a timer for each initiated write operation when the write operation is initiated;

(ii) adding a time value of one timer to the total time after receiving acknowledgment that the write operation for the timer has completed; and

(iii) resetting the total time to zero after gathering the performance data for the second number of write operations; and

means for initiating at least one additional write operation if, after at least one initiated write operation has completed, a number of outstanding write operations is less than a maximum number of write operations; and

means for adjusting the maximum number of write operations if the performance data meets at least one threshold.

21. A system for executing write operations, comprising:

a first storage device;

a second storage device; and

a controller, wherein the controller performs;

(i) initiating a first number of write operations to copy data from the first storage device to the second storage device;

(ii) gathering performance data indicating a total time for a second number of the initiated write operations to complete;

(iv) initiating at least one additional write operation if, after at least one initiated write operation has completed, a number of outstanding write operations is less than a maximum number of write operations; and

(v) adjusting the maximum number of write operations if the performance data meets at least one threshold.

23. An information bearing medium for executing write operations, wherein the information bearing medium includes code capable of causing a processor to perform:

initiating a first number of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold.

24. The information bearing medium of claim 23, wherein the second number is greater than or equal to the first number.

32. The information bearing medium of claim 23, wherein a controller initiates write operations to copy data from a first storage device to a second storage device.

25. An information bearing medium for executing write operations, wherein the information bearing medium includes code capable of causing a processor to perform:

initiating a first number of write operations, wherein the write operations are part of a series of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold, wherein performance data is gathered and adjustments to the maximum number considered each time the second number of write operations are completed while there are further write operations in the series of write operations to perform.

26. An information bearing medium for executing write operations, wherein the information bearing medium includes code capable of causing a processor to perform:

initiating a first number of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete;

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations;

comparing the total time for the second number of write operations to complete with a previous best time for the second number of write operations to complete; and

adjusting the maximum number of write operations if the time for the write operations to complete meets at least one threshold with respect to the previous best time.

27. The information bearing medium of claim 26, wherein adjusting the maximum number comprises adjusting the maximum number upward if the total time exceeds the previous best time by a percentage amount.

28. The information bearing medium of claim 27, further causing the processor to perform initiating at least one additional write operation when adjusting the maximum number upwards.

29. The information bearing medium of claim 26, wherein adjusting the maximum number comprises adjusting the maximum number downward if the total time is less than the previous best time by a percentage amount.

30. The information bearing medium of claim 26, further causing the processor to perform:

setting the best time to the total time if the total time exceeds the best time, wherein the adjusted best time is used when determining whether to adjust the maximum number.

31. An information bearing medium for executing write operations, wherein the information bearing medium includes code capable of causing a processor to perform:

initiating a first number of write operations;

gathering performance data indicating a total time for a second number of the initiated write operations to complete by;

(i) starting a timer for each initiated write operation when the write operation is initiated;

(ii) adding a time value of one timer to the total time after receiving acknowledgment that the write operation for the timer has completed; and

(iii) resetting the total time to zero after gathering the performance data for the second number of write operations; and

after at least one initiated write operation has completed, initiating at least one additional write operation if a number of outstanding write operations is less than a maximum number of write operations; and

adjusting the maximum number of write operations if the performance data meets at least one threshold.

33. The information bearing medium of claim 31, further causing the processor to perform:

transferring, with the first controller, the initiated write operations to a second controller, wherein the second controller executes the write operations against the second storage device.