COUPLED LOCK ALLOCATION AND LOOKUP FOR SHARED DATA SYNCHRONIZATION IN SYMMETRIC MULTITHREADING ENVIRONMENTS

• US 20130046939A1
• Filed: 02/29/2012
• Published: 02/21/2013
• Est. Priority Date: 08/17/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: WADDINGTON, Daniel, Liu, Tongping, Tian, Chen
• Granted Patent: US 8,868,849 B2
• Time in Patent Office: Days
• US Class Current: 711/152
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

In a shared memory process different threads may attempt to access a shared data variable in a shared memory. Locks are provided to synchronize access to shared data variables. Each lock is allocated to have a location in the shared memory relative to the instance of shared data that the lock protects. A lock may be allocated to be adjacent to the data that it protects. Lock resolution is facilitated because the memory location of a lock can be determined from an offset with respect to the data variable that is being protected by the lock.

Claims

1. A method of using locks in a multithreaded computing system having at least two processors or cores and a shared memory process configuration, comprising:

for each instance of shared data in at least a portion of a shared memory, allocating a lock in the shared memory where the lock location is designated according to an offset for the lock with respect to the corresponding respective instance of shared data protected by the lock.

2. The method of claim 1, wherein each of the locks is allocated to be adjacent in memory to the corresponding instance of shared data protected by a particular lock.

3. The method of claim 1, further comprising resolving a lock location for a particular instance of shared data in the shared memory based on the address of the particular instance of shared data adjusted by the offset.

4. The method of claim 1, wherein a particular shared data instance is allocated together with a corresponding lock.

5. The method of claim 1, wherein the locks are automatically allocated by a compiler.

6. The method of claim 1, wherein locks are implicitly defined with respect to the data they protect via a type system such that a programmer does not have to explicitly define locks.

7. A multithreaded computing system comprising:

at least two processors in a shared memory process configuration in which threads of at least two processors access a shared memory, wherein;

accesses to shared data in the shared memory are synchronized for individual instances of shared data via a lock allocation in which the lock location is selected according to an offset for the lock with respect to the corresponding respective instance of shared data protected by the lock.

8. The system of claim 7, wherein each of the locks is allocated to be adjacent in memory to the corresponding instance of shared data protected by a particular lock.

9. The system of claim 7, further comprising resolving a lock location for a particular instance of shared data in the shared memory based on the address of the particular instance of shared data adjusted by the offset.

10. The system of claim 7, wherein a particular shared data instance is allocated together with a corresponding lock.

11. The system of claim 7, wherein the locks are automatically allocated by a compiler.

12. The system of claim 7, wherein locks are implicitly defined with respect to the data they protect via a type system such that a programmer does not have to explicitly define locks.

13. A method of resolving locks in a multithreaded computing system having at least two processors or processor cores and a shared memory process configuration, comprising:

for an instance of an access to shared data in at least a portion of a shared memory, determining a memory location of a lock according to an offset for the lock with respect to the corresponding respective instance of shared data protected by the lock.

14. The method of claim 13, wherein each of the locks is allocated to be adjacent in memory to the corresponding instance of shared data protected by a particular lock.

15. The method of claim 14, further comprising resolving a lock location for a particular instance of shared data in the shared memory based on the address of the particular instance of shared data adjusted by the offset.

16. A multithreaded computing system comprising:

at least two processors in a shared memory process configuration in which threads of the at least two processors access a shared memory, wherein;

lock resolution for a lock to an instance of shared data in a shared memory is determined from a relative position with respect to the memory location of the instance of shared data.

17. The system of claim 16, wherein each of the locks is allocated to be adjacent in memory to the corresponding instance of shared data protected by a particular lock.

18. The system of claim 16, wherein the lock resolution includes adjusting an address of the particular instance of shared data adjusted by an offset.

19. A computer program product comprising computer readable instruction which when executed by a processor implement a method comprising:

for an instance of an access to shared data in at least a portion of a shared memory, determining a memory location of a lock according to an offset for the lock with respect to the corresponding respective instance of shared data protected by the lock.