Locating potential sources of memory leaks

• US 20040078540A1
• Filed: 12/12/2002
• Published: 04/22/2004
• Est. Priority Date: 10/18/2002
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: Computer Associates Think Inc. (Broadcom, Inc.)
• Inventors: Cirne, Lewis K., Puryear, Daryl L., Bley, John B., Latham, David
• Granted Patent: US 7,234,080 B2
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 11/3476 Data logging G06F11/14, G06F11/2205 take precedence
• CPC Class Codes: G06F 11/348 Circuit details, i.e. tracer hardware
• CPC Class Codes: G06F 11/362 Software debugging
• CPC Class Codes: G06F 2201/81 Threshold
• CPC Class Codes: G06F 2201/865 Monitoring of software

Abstract

Potential sources of memory leaks are identified by tracking the size of groups of stored items and determining based on the growth pattern of the groups whether the groups of stored items are potential sources of memory leaks. An example of a group of stored items is an instance of a Java collection. If the growth pattern of a particular group of stored items indicates that it may be the source of a memory leak, that group is reported to a user and will continue to be tracked.

Claims

1. A method of monitoring for potential sources of memory leaks, comprising the steps of:

tracking size of a first group of stored items; and

determining whether said first group of stored items is a potential memory leak source based on change in size of said first group of stored items.

2. A method according to claim 1, wherein:

said first group of stored items is a Java collection.

3. A method according to claim 2, wherein:

said step of determining is based on a growth pattern of said Java collection.

4. A method according to claim 2, wherein said step of determining comprises the steps of:

comparing a recently received size of said first group of stored items to a current value of a threshold; and

reporting that said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

5. A method according to claim 4, wherein:

a size of said set or previous values of said threshold is determined by a changeable sensitivity setting.

6. A method according to claim 4, wherein a first value of said previous values of said threshold was determined by multiplying a growth factor by a previous size.

7. A method according to claim 1, further comprising the step of:

determining that said first group of stored items is no longer the potential memory leak source.

8. A method according to claim 7, wherein said step of determining that said first group of stored items is no longer the potential memory leak source comprises the steps of:

determining whether a current size of said first group of stored items is greater than a current threshold;

determining a number of times said current threshold has been compared to size of said first group of stored items; and

comparing said number of times said current threshold has been compared to a number of times a previous threshold has been compared, said first group of stored items is no longer the potential memory leak source if said number of times said current threshold has been compared is greater than said number of times a previous threshold has been compared.

9. A method according to claim 1, further comprising the steps of:

(a) reporting that said first group of stored items is the potential memory leak source;

(b) reporting that said first group of stored items is no longer the potential memory leak source; and

(c) reporting that said first group of stored items is the potential memory leak source, step (b) is performed after step (a) and step (c) is performed after step (b).

10. A method according to claim 1, wherein:

said step of tracking tracks size for multiple groups of stored items;

said step of determining is performed for said multiple groups of stored items;

if a new group is created during a predetermined period, said step of tracking will track said new group and said step of determining will be performed for said new group during said predetermined period and after said predetermined period; and

if a new group is created after a predetermined period, said step of tracking will not track said new group and said step of determining will not be performed for said new group.

11. A method according to claim 1, further comprising the steps of:

determining that said first group has been created;

determining whether leak detection is enabled in response to said first group being created; and

maintaining a weak reference to said first group.

12. A method according to claim 1, wherein:

said step of tracking tracks size for multiple groups of stored items; and

said step of tracking includes maintaining weak references to said multiple groups of stored items.

13. A method according to claim 1, wherein:

said first group of stored items are Java collections used by an application; and

said steps of tracking and determining are performed using code that is added to said application using bytecode instrumentation.

14. A method according to claim 1, further comprising the steps of:

receiving original bytecode for an application, said first group of stored items is a Java collections used by said application; and

modifying said original bytecode including adding new byte code to said original bytecode, said new byte code enables said steps of tracking and determining.

15. A method according to claim 14, wherein:

said step of determining comprises the steps of comparing a recently received size of said first group of stored items to a current value of a threshold and reporting that of said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

16. A method according to claim 1, wherein:

said step of determining includes reporting about said first group of stored items.

17. A method according to claim 1, wherein:

said steps of tracking and determining are performed by a computing device.

18. A method according to claim 1, wherein:

said steps of tracking and determining are automatically performed by a computing device.

19. A method according to claim 1, wherein:

said first group of stored items are used by an application; and

said steps of tracking and determining are performed during production operation of said application.

20. A method according to claim 1, wherein:

said first group of stored items is a Java collection;

said step of determining comprises the steps of comparing a recently received size of said first group of stored items to a current value of a threshold and reporting that of said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied;

a first value of said previous values of said threshold was determined by multiplying a growth factor by a previous size;

said step of tracking includes maintaining a weak reference to said first group of stored items; and

said method further includes the step of determining that said first group of stored items is no longer the potential memory leak source.

21. One or more processor readable storage devices having processor readable code embodied on said processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising the steps of:

tracking size of a first group of stored items; and

determining whether said first group of stored items is a potential source of a memory leak based on change in said size of said first group of stored items.

22. One or more processor readable storage devices according to claim 21, wherein:

said first group of stored items is a Java collection.

23. One or more processor readable storage devices according to claim 21, wherein said step of determining comprises the steps of:

comparing a recently received size of said first group of stored items to a current value of a threshold; and

reporting that said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

24. One or more processor readable storage devices according to claim 23, wherein a first value of said previous values of said threshold was determined by multiplying a growth factor by a previous size.

25. One or more processor readable storage devices according to claim 21, wherein said method further comprises the step of:

determining that said first group of stored items is no longer the potential memory leak source.

26. One or more processor readable storage devices according to claim 25, wherein said step of determining that said first group of stored items is no longer the potential memory leak source comprises the steps of:

determining whether a current size of said first group of stored items is greater than a current threshold;

determining a number of times said current threshold has been compared to size of said first group of stored items; and

comparing said number of times said current threshold has been compared to a number of times a previous threshold has been compared, said first group of stored items is no longer the potential memory leak source if said number of times said current threshold has been compared is greater than said number of times a previous threshold has been compared.

27. One or more processor readable storage devices according to claim 22, wherein said method further comprises the step of:

(a) reporting that said first group of stored items is the potential memory leak source;

(b) reporting that said first group of stored items is no longer the potential memory leak source; and

(c) reporting that said first group of stored items is the potential memory leak source, step (b) is performed after step (a) and step (c) is performed after step (b).

28. One or more processor readable storage devices according to claim 27, wherein:

said step of tracking tracks size for multiple groups of stored items;

said step of determining is performed for said multiple groups of stored items;

if a new group is created during a predetermined period, said step of tracking will track said new group and said step of determining will be performed for said new group during said predetermined period and after said predetermined period; and

if a new group is created after a predetermined period, said step of tracking will not track said new group and said step of determining will not be performed for said new group.

29. One or more processor readable storage devices according to claim 21, wherein:

said step of tracking tracks size for multiple groups of stored items; and

said step of tracking includes maintaining weak references to said multiple groups of stored items.

30. One or more processor readable storage devices according to claim 21, wherein:

said first group of stored items are used by an application; and

said steps of tracking and determining are performed during production operation of said application.

31. One or more processor readable storage devices according to claim 30, wherein:

said first group of stored items is a Java collection.

32. One or more processor readable storage devices according to claim 31, wherein said step of determining comprises the steps of:

comparing a recently received size of said first group of stored items to a current value of a threshold; and

reporting that of said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

33. An apparatus, comprising:

one or more storage devices; and

one or more processors in communication with said one or more storage devices, said one or more processors perform a method comprising the steps of;

tracking size of a first group of stored items, and

determining whether said first group of stored items is a potential source of a memory leak based on change in said size of said first group of stored items.

34. An apparatus according to claim 33, wherein:

said first group of stored items is a Java collection of objects.

35. An apparatus according to claim 34, wherein said step of determining comprises the steps of:

comparing a recently received size of said first group of stored items to a current value of a threshold; and

reporting that said first group of stored items is said potential memory leak source if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

36. An apparatus according to claim 34, wherein said method further comprises the step of:

determining that said first group of stored items is no longer the potential memory leak source.

37. An apparatus according to claim 34, wherein:

said step of tracking tracks size for multiple groups of stored items; and

said step of tracking includes maintaining weak references to said multiple groups of stored items.

38. An apparatus according to claim 34, wherein:

said first group of stored items are used by an application; and

said steps of tracking and determining are performed during production operation of said application.

39. A method of monitoring for potential sources of memory leaks, comprising the steps of:

automatically tracking size of a first group of stored items; and

automatically determining whether said size of said first group of stored items grows in a manner that suggests a memory leak.

40. A method according to claim 39, wherein:

said first group of stored items is a Java collection.

41. A method according to claim 40, further comprising the step of:

determining in real-time that said first group of stored items is not said potential source of said memory leak.

42. A method according to claim 40, wherein:

said first group of stored items are used by an application; and

said steps of tracking and determining are performed during production operation of said application.

43. One or more processor readable storage devices having processor readable code embodied on said processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising the steps of:

tracking size of a first group of stored items; and

determining whether said size of said first group of stored items has a growth pattern that suggests a memory leak.

44. One or more processor readable storage devices according to claim 43, wherein:

said first group of stored items is a Java collection.

45. One or more processor readable storage devices according to claim 44, wherein said method further comprises the step of:

determining in real-time that said first group of stored items is not a potential source of a memory leak.

46. One or more processor readable storage devices according to claim 45, wherein:

said first group of stored items are used by an application; and

said steps of tracking and determining are performed during production operation of said application.

47. A method of monitoring for potential sources of memory leaks, comprising the steps of:

receiving a size of a group of stored items;

comparing said received size to a current value of a threshold; and

reporting that said group of stored items is a potential source of a memory leak if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

48. A method according to claim 47, wherein:

said group of stored items is a Java collection.

49. A method according to claim 47, wherein:

a size of said set or previous values of said threshold are determined by a changeable sensitivity setting.

50. A method according to claim 47, further comprising the step of:

determining in real time that said first group of stored items is no longer the potential memory leak source.

51. A method according to claim 50, wherein said step of determining in real time that said first group of stored items is no longer the potential source of said memory leak comprises the steps of:

determining whether a current size of said first group of stored items is greater than a current threshold;

determining a number of times said current threshold has been compared to size of said first group of stored items since; and

comparing said number of times said current threshold has been compared to a number of times a previous threshold has been compared, said first group of stored items is no longer the potential source of said memory leak if said number of times said current threshold has been compared is greater than said number of times a previous threshold has been compared.

52. A method according to claim 51, wherein:

said group of stored items is a Java collection of objects.

53. A method according to claim 47, further comprising the steps of:

(a) reporting that said first group of stored items is the potential source of the memory leak;

(b) reporting that said first group of stored items is no longer the potential source of the memory leak; and

(c) reporting that said first group of stored items is the potential memory leak source of the memory leak, step (b) is performed after step (a) and step (c) is performed after step (b).

54. One or more processor readable storage devices having processor readable code embodied on said processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising the steps of:

receiving a size of a group of stored items;

comparing said received size to a current value of a threshold; and

determining that said group of stored items is a potential source of a memory leak if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

55. One or more processor readable storage devices according to claim 54, wherein:

said group of stored items is a Java collection of objects.

56. One or more processor readable storage devices according to claim 54, wherein:

a size of said set or previous values of said threshold are determined by a changeable sensitivity setting.

57. One or more processor readable storage devices according to claim 55, further comprising the step of:

determining that said first group of stored items is not said potential source of said memory leak.

58. One or more processor readable storage devices according to claim 57, wherein said step of determining in real time that said first group of stored items is no longer the potential source of said memory leak comprises the steps of:

determining whether a current size of said first group of stored items is greater than a current threshold;

determining a number of times said current threshold has been compared to size of said first group of stored items since; and

comparing said number of times said current threshold has been compared to a number of times a previous threshold has been compared, said first group of stored items is no longer the potential source of said memory leak if said number of times said current threshold has been compared is greater than said number of times a previous threshold has been compared.

59. One or more processor readable storage devices according to claim 58, wherein:

said group of stored items is a Java collection of objects.

60. An apparatus, comprising:

one or more storage devices; and

one or more processors in communication with said one or more storage devices, said one or more processors perform a method comprising the steps of;

receiving a size of an instance of a collection, comparing said received size to a current value of a threshold, and

determining that said instance of said collection is a potential source of a memory leak if said received size satisfies said current value of said threshold and a set of previous values of said threshold have also been satisfied.

61. An apparatus, comprising:

one or more storage devices; and

one or more processors in communication with said one or more storage devices, said one or more processors perform a method comprising the steps of;

tracking size of a first instance of a collection, and

determining whether said size of said first instance of said collection grows in a manner that suggests a memory leak.