Multi-threaded break-point

• US 6,681,384 B1
• Filed: 12/23/1999
• Issued: 01/20/2004
• Est. Priority Date: 12/23/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Day, Paul Reuben, Bates, Cary Lee
• Primary Examiner(s): DAS, CHAMELI
• Application Number:
  US09/470,839
• Time in Patent Office: 1,489 Days
• Field of Search: 717/124, 717/129, 717/127, 717/128, 717/130, 717/126, 717/131, 717/151, 717/140, 714/707, 714/34, 714/47, 714/51, 714/775, 714/35
• US Class Current: 717/129
• CPC Class Codes: G06F 11/3632 of specific synchronisation aspects
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A way to synchronize threads in a multi-threaded program. In the preferred embodiment, a debugger provides a break-point that does not interrupt the user when the first thread reaches it; instead, the debugger halts this thread at the break-point and waits for other threads to accumulate at the break-point before the debugger notifies the user. The user can specify a condition under which this notification should occur; for example, when a specific thread or a certain number of threads have accumulated at the break-point. Once the condition is satisfied, the debugger suspends other threads that have not reached the break-point. The debugger then provides for synchronized stepping or running of the threads that are halted at the break-point.

Claims

1. A method of synchronizing execution of a multi-thread program, comprising the computer-executed steps:

executing the multi-thread program, wherein the multi-thread program comprises a plurality of threads;

halting execution of a first thread at a synchronization break-point;

while the first thread is halted, continuing execution of other of the plurality of threads that have not yet reached the synchronization break-point;

thereafter determining that a synchronization break condition has been satisfied, while said first thread remains halted, wherein said synchronization break condition includes at least one condition from the set consisting of;

(a) determining that a pre-determined number of the plurality of threads have reached the synchronization break-point,

(b) determining that a pre-determined amount of time has elapsed since said first thread reached the synchronization break-point, and

(c) determining that a user-specified thread has reached the synchronization break-point; and

responsive to determining that a synchronization break condition has been satisfied, halting execution of all threads of said multi-thread program.

2. The method of claim 1, further comprising:

halting any of the other threads that subsequently reach the synchronization break-point before said step of determining that a break condition has been satisfied.

3. The method of claim 1, wherein the break condition further comprises:

determining that a pre-determined number of the plurality of threads have reached the synchronization break-point.

4. The method of claim 3, wherein the predetermined number is user-specified.

5. The method of claim 1, wherein the break condition further comprises:

determining that a pre-determined amount of time has elapsed since said first thread reached the synchronization break-point.

6. The method of claim 5, wherein the pre-determined amount of time is user-specified.

7. The method of claim 1, wherein the break condition further comprises:

determining that a user-specified thread has reached the synchronization break-point.

8. The method of claim 1, further comprising:

executing a next statement after the synchronization break-point in a last thread that was halted.

9. The method of claim 1, further comprising:

executing a next statement after the synchronization break-point in all threads that were halted.

10. The method of claim 1, further comprising:

resuming execution of the other threads that have not reached the synchronization break-point.

11. An apparatus comprising:

a processor;

a memory coupled to the processor;

a multi-threaded program resident in memory and executing on the processor, the program comprising a plurality of threads; and

a debug controller, resident in the memory and executing on the processor, wherein the debug controller is configured to execute a portion of the multi-threaded program for debugging, wherein the debug controller, when read and executed by the processor, comprises steps of;

executing the multi-thread program, wherein the multi-thread program comprises a plurality of threads,

halting execution of a first thread at a synchronization break-point,

while the first thread is halted, continuing execution of other of the plurality of threads that have not yet reached the synchronization break-point;

thereafter determining that a synchronization break condition has been satisfied, while said first thread remains halted, wherein said synchronization break condition includes at least one condition from the set consisting of;

(a) determining that a pre-determined number of the plurality of threads have reached the synchronization break-point,

(b) determining that a pre-determined amount of time has elapsed since said first thread reached the synchronization break-point, and

(c) determining that a user-specified thread has reached the synchronization break-point; and

responsive to determining that a synchronization break condition has been satisfied, halting execution of all threads of said multi-threaded program.

12. The apparatus of claim 11, further comprising:

halting any of the other threads that subsequently reach the synchronization break-point before said step of determining that a break condition has been satisfied.

13. The apparatus of claim 11, wherein the break condition further comprises:

determining that a pre-determined number of the plurality of threads have reached the synchronization break-point.

14. The apparatus of claim 13, wherein the predetermined number is user-specified.

15. The apparatus of claim 11, wherein the break condition further comprises:

determining that a pre-determined amount of time has elapsed since said first thread reached the synchronization break-point.

16. The apparatus of claim 15, wherein the pre-determined amount of time is user-specified.

17. The apparatus of claim 11, wherein the break condition further comprises:

determining that a user-specified thread has reached the synchronization break-point.

18. The apparatus of claim 11, further comprising:

executing a next statement after the synchronization break-point in a last thread that was halted.

19. The apparatus of claim 11, further comprising:

executing a next statement after the synchronization break-point in all threads that were halted.

20. The apparatus of claim 11, further comprising:

resuming execution of the other threads that have not reached the synchronization break-point.

21. The apparatus of claim 11, further comprising a break-point table, wherein the break-point table defines the synchronization break-points.

22. A program product, comprising:

a debug controller configured to execute a portion of multi-thread program for debugging, the program comprising a plurality of threads, and the debug controller is configured to execute a portion of the multi-threaded program for debugging, wherein the debug controller, when read and executed by the processor, comprises steps of;

executing the multi-thread program, wherein the multi-thread program comprises a plurality of threads,

halting execution of a first thread at a synchronization break-point,

while the first thread is halted, continuing execution of other of the plurality of threads that have not yet reached the synchronization break-point;

thereafter determining that a synchronization break condition has been satisfied, while said first thread remains halted, wherein said synchronization break condition includes at least one condition from the set consisting of;

(a) determining that a pre-determined number of the plurality of threads have reached the synchronization break-point,

(b) determining that a predetermined amount of time has elapsed since said first thread reached the synchronization break-point, and

(c) determining that a user-specified thread has reached the synchronization break-point; and

; and

responsive to determining that a break condition has been satisfied, halting execution of all threads of said multi-thread program.

23. The program product of claim 22, further comprising:

halting any of the other threads that subsequently reach the synchronization break-point before said step of determining that a break condition has been satisfied.

24. The program product of claim 22, wherein the break condition further comprises:

determining that a pre-determined number of the plurality of threads have reached the synchronization break-point.

25. The program product of claim 24, wherein the predetermined number is user-specified.

26. The program product of claim 22, wherein the break condition further comprises:

determining that a pre-determined amount of time has elapsed since said first thread reached the synchronization break-point.

27. The program product of claim 26, where in the pre-determined amount of time is user-specified.

28. The program product of claim 22, wherein the break condition further comprises:

determining that a user-specified thread has reached the synchronization break-point.

29. The program product of claim 22, further comprising:

executing a next statement after the synchronization break-point in a last thread that was halted.

30. The program product of claim 22, further comprising:

executing a next statement after the synchronization break-point in all threads that were halted.

31. The program product of claim 22, further comprising:

resuming execution of the other threads that have not reached the synchronization break-point.

32. The program product of claim 22, further comprising a break-point table, wherein the break-point table defines the synchronization break-point.