Thread synchronization with lock inflation methods and apparatus for managed run-time environments

• US 20050289546A1
• Filed: 06/28/2004
• Published: 12/29/2005
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Shpeisman, Tatiana, Murphy, Brian, Adl-Tabatabai, Ali-Reza
• Granted Patent: US 7,567,963 B2
• Time in Patent Office: Days
• US Class Current: 718/100
• CPC Class Codes: G06F 9/3004 to perform operations on memory
• CPC Class Codes: G06F 9/30087 Synchronisation or serialisation instructions
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/528 by using speculative mechanisms

Abstract

Thread synchronization with lock inflation methods and apparatus for managed run-time environments are disclosed. An example method disclosed herein comprises determining a locking operation to perform on a lock corresponding to the object, performing an optimistically balanced synchronization of the lock if the locking operation is not unbalanced, and modifying a lock shape of the lock if the locking operation is unbalanced.

Claims

1. A method to lock an object for a thread in a managed run-time environment comprising:

determining a locking operation to perform on a lock corresponding to the object;

performing an optimistically balanced synchronization of the lock if the locking operation is not unbalanced; and

modifying a lock shape of the lock if the locking operation is unbalanced.

2. A method as defined in claim 1 further comprising performing at least one of an unbalanced lock acquisition of the lock and an unbalanced release of the lock if the locking operation is unbalanced.

3. A method as defined in claim 1 wherein the lock shape corresponds to at least one of a first lock shape and a second lock shape, and wherein modifying the lock shape comprises converting the lock to correspond to the second lock shape if the lock shape corresponds to the first lock shape.

4. A method as defined in claim 3 wherein the first lock shape corresponds to a thin lock and the second lock shape corresponds to an inflated lock.

5. A method as defined in claim 1 wherein the optimistically balanced synchronization comprises setting a lock shape flag to indicate the lock shape of the lock during the optimistically balanced synchronization.

6. A method as defined in claim 1 wherein the optimistically balanced synchronization comprises an optimistically balanced lock acquisition of the lock and an optimistically balanced lock release of the lock, and wherein at least one of the optimistically balanced lock acquisition and the optimistically balanced lock release is performed based on the lock shape of the lock.

7. A method as defined in claim 6 wherein the optimistically balanced lock acquisition comprises setting a previous lock owner equal to a lock owner field associated with the lock if the lock shape corresponds to a first lock shape.

8. A method as defined in claim 6 wherein the optimistically balanced lock release comprises setting a lock owner field associated with the lock to a previous lock owner if the lock shape corresponds to a first lock shape.

9. A method as defined in claim 8 wherein, if the lock shape corresponds to the first lock shape, the lock is unlocked if the previous lock owner is a null thread and the lock is maintained for the thread if the previous lock owner is the thread.

10. A method as defined in claim 1 wherein the optimistically balanced synchronization comprises maintaining a synchronization map to store a set of active optimistically balanced acquisition states associated with a set of optimistically balanced synchronizations performed on the lock of the object.

11. A method as defined in claim 10 further comprising performing at least one of an unbalanced acquisition of the lock and an unbalanced release of the lock if the locking operation is unbalanced, and wherein performing the at least one of the unbalanced acquisition and the unbalanced release comprises determining a number of active optimistically balanced acquisition states stored in the synchronization map.

12. A method as defined in claim 11 wherein modifying the lock shape of the lock comprises determining a lock recursion count value corresponding to the number of active optimistically balanced acquisition states stored in the synchronization map.

13. A method as defined in claim 10 wherein the synchronization map comprises a set of synchronization map entries corresponding to the set of active optimistically balanced acquisition states, and wherein a synchronization map entry in the set of synchronization map entries comprises at least one of a previous lock owner of the lock and a lock shape flag corresponding to the lock shape of the lock.

14. A method as defined in claim 13 wherein modifying the lock shape of the lock comprises modifying the lock shape flag in the synchronization map entry.

15. A method as defined in claim 1 wherein determining the locking operation to perform on the lock comprises determining whether the locking operation is one of the optimistically balanced synchronization of the lock, a balanced synchronization of the lock, an unbalanced acquisition of the lock and an unbalanced release of the lock.

16. An article of manufacture storing machine readable instructions that, when executed, cause a machine to:

determine a locking operation to perform on a lock corresponding to the object;

perform an optimistically balanced synchronization of the lock if the locking operation is not unbalanced; and

modify a lock shape of the lock if the locking operation is unbalanced.

17. An article of manufacture as defined in claim 16 wherein the lock shape corresponds to at least one of a first lock shape and a second lock shape, and wherein to modify the lock shape the machine readable instructions cause the machine to convert the lock to correspond to the second lock shape if the lock shape corresponds to the first lock shape.

18. An article of manufacture as defined in claim 16 wherein the machine readable instructions cause the machine to maintain a synchronization map to store a set of synchronization map entries corresponding to a set of active optimistically balanced acquisition states associated with a set of optimistically balanced synchronizations performed on the lock of the object, and wherein a synchronization map entry in the set of synchronization map entries comprises at least one of a previous lock owner of the lock and a lock shape flag corresponding to the lock shape of the lock.

19. An article of manufacture as defined in claim 18 wherein the machine readable instructions cause the machine to perform at least one of an unbalanced acquisition of the lock and an unbalanced release of the lock if the locking operation on the lock is unbalanced, and wherein to perform the at least one of the unbalanced acquisition and the unbalanced release, the machine readable instructions cause the machine to at least one of determine the number of active optimistically balanced acquisition states stored in the synchronization map and modify at least one lock shape flag in at least one synchronization map entry of the synchronization map.

20. An apparatus to lock an object for a thread in a managed run-time environment comprising:

an optimistically balanced lock synchronization unit to perform an optimistically balanced synchronization of a lock corresponding to the object; and

a balanced synchronization state tracker/modifier to at least one of determine and modify a state of the optimistically balanced synchronization unit based on an occurrence of at least one of an unbalanced lock acquisition of the lock and an unbalanced lock release of the lock.

21. An apparatus as defined in claim 20 wherein the optimistically balanced lock synchronization unit is configured to:

acquire the lock by setting a previous lock owner of the lock equal to a lock owner field of the lock if the lock shape is a first lock shape; and

release the lock by resetting the lock owner field equal to the previous lock owner if the lock shape is the first lock shape.

22. An apparatus as defined in claim 20 wherein the optimistically balanced lock synchronization unit is configured to set a lock shape flag to indicate the lock shape of the lock during an optimistically balanced synchronization operation performed on the lock.

23. An apparatus as defined in claim 20 wherein the optimistically balanced lock synchronization unit comprises a synchronization map to store a set of active optimistically balanced acquisition states corresponding to a set of optimistically balanced synchronizations performed on the lock of the object.

24. An apparatus as defined in claim 23 wherein the synchronization map comprises a set of synchronization map entries corresponding to the set of active optimistically balanced acquisition states, and wherein a synchronization map entry in the set of synchronization map entries comprises at least one of a previous lock owner of the lock and a lock shape flag corresponding to the lock shape of the lock.

25. An apparatus as defined in claim 24 wherein the balanced synchronization state tracker/modifier is configured to at least one of determine the state of the optimistically balanced synchronization unit by determining the number of active optimistically balanced acquisition states stored in the synchronization map and modify the state of the optimistically balanced synchronization unit by modifying at least one lock shape flag in at least one synchronization map entry of the synchronization map.

26. An apparatus as defined in claim 20 wherein the optimistically balanced synchronization comprises an optimistically balanced acquisition of the lock and an optimistically balanced release of the lock, and wherein the optimistically balanced synchronization unit is configured to perform at least one of the optimistically balanced acquisition and the optimistically balanced release based on the lock shape of the lock.

27. An apparatus as defined in claim 20 further comprising at least one of an unbalanced lock acquisition unit to perform an unbalanced acquisition of the lock and an unbalanced lock release unit to perform an unbalanced release of the lock, and wherein the at least one of the unbalanced lock acquisition unit and the unbalanced lock release unit is configured to modify the lock shape of the lock.

28. A system to lock an object for a thread in a managed run-time environment comprising:

a processor configured to;

determine a locking operation to perform on a lock corresponding to the object;

perform an optimistically balanced synchronization of the lock if the locking operation is not unbalanced; and

modify a lock shape of the lock if the locking operation is unbalanced; and

a memory to store at least one of a lock owner field of the lock, a previous lock owner of the lock and a lock shape flag corresponding to the lock shape of the lock.

29. A system as defined in claim 28 wherein the processor is configured to store a synchronization map in the memory comprising a set of synchronization map entries corresponding to a set of active optimistically balanced acquisition states associated with a set of optimistically balanced synchronizations performed on the lock of the object, and wherein a synchronization map entry in the set of synchronization map entries comprises at least one of a previous lock owner of the lock and a lock shape flag corresponding to the lock shape of the lock.

30. A system as defined in claim 29 wherein the processor is configured to perform at least one of an unbalanced acquisition of the lock and an unbalanced release of the lock if the locking operation on the lock is unbalanced, and wherein to perform the at least one of the unbalanced acquisition and the unbalanced release, the processor is configured to at least one of determine the number of active optimistically balanced acquisition states stored in the synchronization map and modify at least one lock shape flag in at least one synchronization map entry of the synchronization map.