BUSY-WAIT TIME FOR THREADS

• US 20110167428A1
• Filed: 01/07/2010
• Published: 07/07/2011
• Est. Priority Date: 01/07/2010
• Status: Active Grant

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: GEORGE, Sherin Thyil, CHANDRAMOULEESWARAN, Aswin, SASIDHARAN NAIR, Rakesh
• Granted Patent: US 8,769,546 B2
• Time in Patent Office: Days
• US Class Current: 718/106
• CPC Class Codes: G06F 9/524 Deadlock detection or avoidance

Abstract

Method to selectively assign a reduced busy-wait time to threads is described. The method comprises determining whether at least one thread is spinning on a mutex lock associated with a condition variable and assigning, when the at least one thread is spinning on the mutex lock, a predetermined reduced busy-wait time for a subsequent thread spinning on the mutex lock.

Claims

1. A method comprising:

determining whether at least one thread is spinning on a mutex lock associated with a condition variable; and

assigning, when the at least one thread is spinning on the mutex lock, a predetermined reduced busy-wait time for a subsequent thread spinning on the mutex lock.

2. The method as claimed in claim 1, further comprising

determining, when no thread is spinning on the mutex lock, whether at least one other thread is waiting on the condition variable;

and

assigning the predetermined reduced busy-wait time for the subsequent thread spinning on the mutex lock.

3. The method as claimed in claim 1, wherein the method further comprises determining whether the mutex lock is associated with the condition variable.

4. The method as claimed in claim 1, wherein the predetermined reduced busy-wait time is deterministically computed.

5. A device comprising:

a processor;

a memory coupled to the processor, the memory comprising;

a thread identification module configured to at least determine whether at least one thread is waiting on a condition variable associated with a mutex lock; and

a spin control module configured to assign, based on the determination by the thread identification module, at least one of a predetermined reduced busy-wait time and a default busy-wait time for a subsequent thread.

6. The device as claimed in claim 5, wherein the thread identification module is configured to further determine whether the at least one thread is spinning on the mutex lock.

7. The device as claimed in claim 6, wherein the spin control module is configured to assign the predetermined reduced busy-wait time for the subsequent thread when the at least other thread is spinning on the mutex lock.

8. The device as claimed in claim 6, wherein the spin control module is configured to assign the default busy-wait time when neither the at least one other thread is spinning on the mutex lock nor the at least one thread is waiting on the condition variable associated with the mutex lock.

9. The device as claimed in claim 5, wherein the spin control module is configured to assign the default busy-wait time for the subsequent thread when the condition variable is not associated with the mutex lock.

10. The device as claimed in claim 5, wherein the spin control module is further configured to determine an association of the mutex lock with the condition variable.

11. The device as claimed in claim 5, wherein the at least one thread and the subsequent thread are one of a master thread and a worker thread.

12. A computer-readable medium having computer-executable instructions that when executed, perform acts comprising:

determining whether the mutex lock is associated with a condition variable, wherein the mutex lock is acquired by a thread;

determining whether at least one of,

one or more other threads are spinning on the mutex lock; and

one or more other threads are waiting on the condition variable;

and

assigning, based on the determining, a predetermined reduced busy-wait time to a subsequent thread spinning on the mutex lock.

13. The computer readable medium as claimed in claim 12, further comprising instructions for associating a default busy-wait time to the subsequent thread if the mutex lock is not associated with the condition variable.

14. The computer readable medium as claimed in claim 12, further comprising instructions for assigning a default busy-wait time for the subsequent thread, when only the subsequent thread is spinning on the mutex lock

15. The computer readable medium as claimed in claim 13, wherein the predetermined reduced busy-wait time is less than the default busy-wait time by at least three orders of magnitude.