Apparatus and method for direct switching of software threads

• US 20090037927A1
• Filed: 07/30/2007
• Published: 02/05/2009
• Est. Priority Date: 07/30/2007
• 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: Sangili, Vasudevan, Sharpe, Edward J., Parekh, Harshadrai
• Granted Patent: US 8,584,138 B2
• Time in Patent Office: Days
• US Class Current: 718/108
• CPC Class Codes: G06F 9/461 Saving or restoring of program or task context
• CPC Class Codes: G06F 9/485 Task life-cycle, e.g. stopping, restarting, resuming execution G06F9/4881 takes precedence

Abstract

An embodiment of the invention provides an apparatus and a method for direct switching of software threads. The apparatus and method include performing acts including: issuing a wakeup call from a first thread to a second thread in a sleep state; removing the second thread from the sleep state; switching out the first thread from the resource; switching in the second thread to the resource; and running the second thread on the resource.

Claims

1. A method for direct switching of software threads, the method comprising:

issuing a wakeup call from a first thread to a second thread in a sleep state;

removing the second thread from the sleep state;

switching out the first thread from the resource;

switching in the second thread to the resource; and

running the second thread on the resource.

2. The method of claim 1, wherein switching out the first thread comprises:

placing the first thread in a run queue.

3. The method of claim 1, further comprising:

checking a selection criteria to determine if direct switching of the second thread into the resource is permissible.

4. The method of claim 1, wherein the resource comprises a processor resource.

5. The method of claim 1, wherein the second thread runs on the resource for a remaining timeslice value that is not used by the first thread.

6. The method of claim 1, further comprising:

switching out the first thread and switching in the second thread to the resource if the first thread and second thread are bound to a same locality domain.

7. The method of claim 1, further comprising:

switching out the first thread and switching in the second thread to the resource if the first thread and second thread are bound to different locality domains and the second thread has been in the sleep state beyond a threshold time value.

8. The method of claim 1, further comprising:

avoiding in switching out the first thread and avoiding in switching in the second thread to the resource if the first thread and second thread are bound to different locality domains and the second thread has not been in the sleep state beyond a threshold time value.

9. The method of claim 1, further comprising:

switching out the first thread and switching in the second thread to the resource based on particular resources held by the first thread and resources that the second thread is waiting to obtain.

12. The apparatus of claim 10 of claim 1, wherein the scheduler is configured to check a selection criteria to determine if direct switching of the second thread into the resource is permissible.

10. An apparatus for direct switching of software threads, the apparatus comprising:

a first thread;

a second thread;

wherein the first thread is configured to issue a wakeup call to the second thread in a sleep state; and

a scheduler configured to remove the second thread from the sleep state, switch out the first thread from the resource, switch in the second thread to the resource, and run the second thread on the resource.

11. The apparatus of claim 10, wherein the scheduler is configured to switch out the first thread by placing the first thread in a run queue.

13. The apparatus of claim 10, wherein the resource comprises a processor resource.

14. The apparatus of claim 10, wherein the second thread is configured to run on the resource for a remaining timeslice value that is not used by the first thread.

15. The apparatus of claim 10, wherein the scheduler is configured to switch out the first thread and switch in the second thread to the resource if the first thread and second thread are bound to a same locality domain.

16. The apparatus of claim 10, wherein the scheduler is configured to switch out the first thread and switch in the second thread to the resource if the first thread and second thread are bound to different locality domains and the second thread has been in the sleep state beyond a threshold time value.

17. The apparatus of claim 10, wherein the scheduler is configured to avoid in switching out the first thread and avoid in switching in the second thread to the resource if the first thread and second thread are bound to different locality domains and the second thread has not been in the sleep state beyond a threshold time value.

18. The apparatus of claim 10, wherein the scheduler is configured to switch out the first thread and switch in the second thread to the resource based on particular resources held by the first thread and resources that the second thread is waiting to obtain.

19. An apparatus for direct switching of software threads, the apparatus comprising:

means for issuing a wakeup call from a first thread to a second thread in a sleep state;

means for removing the second thread from the sleep state;

means for switching out the first thread from the resource;

means for switching in the second thread to the resource; and

means for running the second thread on the resource.

20. The apparatus of claim 19, further comprising:

means for checking a selection criteria to determine if direct switching of the second thread into the resource is permissible.

21. An article of manufacture comprising:

a machine-readable medium having stored thereon instructions to;

issue a wakeup call from a first thread to a second thread in a sleep state;

remove the second thread from the sleep state;

switch out the first thread from the resource;

switch in the second thread to the resource; and

run the second thread on the resource.

22. The article of manufacture of claim 21 wherein the instructions will check a selection criteria to determine if direct switching of the second thread into the resource is permissible.