SYSTEM AND METHOD TO REDUCE OVERHEAD OF REFERENCE COUNTING

• US 20180232304A1
• Filed: 02/16/2017
• Published: 08/16/2018
• Est. Priority Date: 02/16/2017
• Status: Abandoned Application

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wang, Haichuan, Ma, Lin, Zheng, Ruohuang, Yang, Xuejun
• Application Number:
  US15/434,270
• Publication Number:
  US 20180232304A1
• Time in Patent Office: Days
• CPC Class Codes: G06F 12/0261 using reference counting
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 2212/1016 Performance improvement

Abstract

The disclosure relates to technology for reference counting. A global reference counter associated with a lock to count one or more threads of a process referencing an object allocated in the memory is established. Each reference to the object by a thread is then tracked using a corresponding local reference counter. The global reference counter is updated whenever a reference to the object by each of the one or more threads is an initial reference or a final reference. Otherwise, local counters are used to track a local reference count of the object.

Claims

1. An device for reference counting, comprising:

a non-transitory memory storage comprising instructions; and

one or more processors in communication with the memory, wherein the one or more processors execute the instructions to perform operations comprising;

establishing a global reference counter associated with a lock to count one or more threads of a process referencing an object allocated in the memory;

tracking, by each of the threads, each reference to the object by the thread using a corresponding local reference counter; and

updating the global reference counter whenever a reference to the object by each of the one or more threads is and initial reference to the object or final reference to the object.

2. The device of claim 1, wherein tracking, by a first thread, a reference to the object by the first thread using a corresponding local reference counter comprises:

determining whether the reference by the thread is the initial reference to the object;

in response to determining that reference to the object is the initial reference to the object;

the updating comprising increasing the global reference counter and initializing the local reference counter with a zero value;

and

increasing the local reference counter without locking the local reference counter.

3. The device of claim 1, wherein tracking, by a first thread, a reference to the object by the first thread using a corresponding local reference counter comprises:

decreasing the local reference counter without locking the local reference counter;

determining whether the local reference counter has a zero value;

in response to determining that the local reference counter has a non-zero value, the updating comprising decreasing the global reference counter; and

releasing the object from the memory when the global reference counter is updated to a zero value.

4. The device of claim 1, wherein a first of the one or more threads corresponds to a first local reference counter and second of the one or more threads corresponds to a second local reference counter, and wherein the operations further comprise:

increasing the first local reference counter when the first thread references the object and decreasing the first local reference counter when the first thread no longer references the object;

increasing the second local reference counter when the second thread references the object and decreasing the second local reference counter when the second thread no longer references the object; and

releasing the object from the memory and the lock associated with the global reference counter when the first local counter and the second local counter have a zero value.

5. The device of claim 1, wherein the corresponding local reference counter employs a lock-free reference count.

6. The device of claim 1, wherein the global reference counter has a count value equal to a number of references by the one or more threads to the object in the memory.

7. The device of claim 4, wherein the operations further comprise:

updating a layout of the object to include the global reference counter; and

mapping an address of the object to a local address of each of the first and second corresponding local reference counters.

8. The device of claim 7, wherein mapping an address of the object to a local address of each of the first and second local reference counters comprises one of:

(1) mapping the shared object address to addresses of the first and second local reference counters by changing associated page addresses,

(2) using a hashmap to store a mapping of an address of the object to a local address of the associated reference counter, and

(3) employing the first and second local reference counters when satisfying an activity level threshold for the one or more threads.

9. The device of claim 1, wherein the lock is retrieved from a lock manager and is coupled to a distributed data store to

lock access to the object,

grant a lock to the process for the object stored in the memory, and

prevent other processes from accessing the object while locked.

10. The device of claim 7, wherein the object is a class instance of a programming language.

11. A computer-implemented method for reference counting, comprising:

establishing a global reference counter associated with a lock to count one or more threads of a process referencing an object allocated in the memory;

tracking, by each of the threads, each reference to the object by the thread using a corresponding local reference counter; and

updating the global reference counter whenever a reference to the object by each of the one or more threads is an initial reference to the object or a final reference to the object.

12. The method of claim 11, wherein tracking, by a first thread, a reference to the object by the first thread using a corresponding local reference counter comprises:

determining whether the reference by the thread is the initial reference to the object;

in response to determining that reference to the object is the initial reference to the object;

the updating comprises increasing the global reference counter and initializing the local reference counter with a zero value; and

increasing the local reference counter without locking the local reference counter.

13. The method of claim 11, wherein tracking, by a first thread, a reference to the object by the first thread using a corresponding local reference counter comprises:

decreasing the local reference counter without locking the local reference counter;

determining whether the local reference counter has a zero value;

in response to determining that the local reference counter has a non-zero value, the updating comprising decreasing the global reference counter; and

releasing the object from the memory when the global reference counter is updated to a zero value.

14. The method of claim 11, wherein a first of the one or more threads corresponds to a first local reference counter and second of the one or more threads corresponds to a second local reference counter, and further comprising:

increasing the first local reference counter when the first thread references the object and decreasing the first local reference counter when the first thread no longer references the object;

increasing the second local reference counter when the second thread references the object and decreasing the second local reference counter when the second thread no longer references the object; and

releasing the object from the memory and the lock associated with the global reference counter when the first local counter and the second local counter have a zero value.

15. The method of claim 11, wherein the corresponding local reference counter employs a lock-free reference count.

16. The method of claim 11, wherein the global reference counter has a count value equal to a number of references by the one or more threads to the object in the memory.

17. The method of claim 14, further comprising:

updating a layout of the object to include the global reference counter; and

mapping an address of the object to a local address of each of the first and second corresponding local reference counters.

18. The method of claim 17, wherein mapping an address of the object to a local address of each of the first and second local reference counters further comprises one of:

(1) mapping the shared object address to addresses of the first and second local reference counters by changing associated page addresses,

(2) using a hashmap to store a mapping of an address of the object to a local address of the associated reference counter, and

(3) employing the first and second local reference counters when satisfying an activity level threshold for the one or more threads.

19. A non-transitory computer-readable medium storing computer instructions for accessing cloud-based phone services over a distributed network by a remote device, that when executed by one or more processors, perform the steps of:

establishing a global reference counter associated with a lock to count one or more threads of a process referencing an object allocated in the memory;

tracking, by each of the threads, each reference to the object by the thread using a corresponding local reference counter; and

updating the global reference counter whenever a reference to the object by each of the one or more threads is and initial reference to the object or final reference to the object.

20. The non-transitory computer-readable medium of claim 19, wherein tracking, by a firth thread, a reference to the object by the first thread using a corresponding local reference counter, causing the one or more processors to further performs the steps of:

determining whether the reference by the thread is an initial reference to the object;

in response to determining that reference to the object is the initial reference to the object;

the updating comprising increasing the global reference counter and initializing the local reference counter with a zero value; and

increasing the local reference counter without locking the local reference counter.

21. The non-transitory computer-readable medium of claim 19, wherein tracking, by a firth thread, a reference to the object by the first thread using a corresponding local reference counter, causing the one or more processors to further performs the steps of:

decreasing the local reference counter without locking the local reference counter;

determining whether the local reference counter has a zero value;

in response to determining that the local reference counter has a non-zero value, the updating comprising decreasing the global reference counter; and

releasing the object from the memory when the global reference counter is updated to a zero value.