PLACEMENT OF A PROCESSING UNIT IN UNFAIR LOCK MODE IN RESPONSE TO A QUEUE IN A FAIR LOCK MODE

• US 20180004411A1
• Filed: 06/30/2016
• Published: 01/04/2018
• Est. Priority Date: 06/30/2016
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Inventors: Long, Wai Man
• Granted Patent: US 9,959,055 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 2009/4557 Distribution of virtual machine instances; Migration and load balancing
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

Examples herein disclose identification of a presence of a processing unit that is to obtain the lock within a queue in a fair lock mode. In response to the presence of the processing unit within the queue, the examples place a separate processing unit in an unfair lock mode.

Claims

1. A method to obtain a lock, the method comprising:

identifying a presence of a processing unit that is to obtain the lock within a queue in a fair lock mode; and

in response to the presence of the processing unit within the queue, placing a separate processing unit in an unfair lock mode.

2. The method of claim 1 comprising:

in response to an empty queue, placing the separate processing unit in the queue in the fair lock mode.

3. The method of claim 1 comprising:

identifying a status of a queue head;

based on the identification of an active status of the queue head, proceeding to place the separate processing unit in the queue; and

based on the identification of an inactive status of the queue head and the presence of the processing unit within the queue, proceeding to place the separate processing unit in the unfair lock mode.

4. The method of claim 1 comprising:

transferring the separate processing unit from the unfair lock mode to the fair lock mode via placement of the queue.

5. The method of claim 1 wherein the fair lock mode and the unfair lock mode operate as spinlocks.

6. The method of claim 1 comprising:

acquiring the lock by the separate processing unit; and

setting a value in the lock by the separate processing unit to indicate the acquirement of the lock.

7. The method of claim 1 wherein the fair lock mode and the unfair lock mode operate in a virtualized environment.

8. A lock system comprising:

a queue to;

operate in a fair spinlock mode; and

list which processing unit is to obtain a lock;

a separate processing unit that;

determine a presence of a processing unit with the queue; and

operate in an unfair spinlock mode in response to the presence of the processing unit within the queue.

9. The lock system of claim 8 wherein the separate processing unit to:

identify a status of a queue head; and

based on confirmation of an inactive status of the queue head and in response to the presence of the processing unit within the queue, operate in the unfair spinlock mode.

10. The lock system of claim 9 wherein the separate processing unit:

based on a confirmation of an active status of the queue head and in response to the presence of the processing unit within the queue, operate in the fair spinlock mode.

11. A non-transitory machine-readable storage medium comprising instructions that when executed by a processing resource cause a computing device to:

determine a presence of a processing unit within a queue that is obtain a lock in a fair lock mode;

identify a status of a queue head; and

in response to the presence of the processing unit within the queue and identification of an inactive status of the queue head, place a separate processing unit in an unfair lock mode.

12. The non-transitory machine-readable storage medium of claim 11 wherein to confirm the inactive state of the queue head comprises instructions that when executed by the processing resource cause the computing device to:

in response to the presence of the processing unit within the queue and identification of an active status of the queue head, place the separate processing unit in the queue in the fair lock mode.

13. The non-transitory machine-readable storage medium of claim 11 comprising instructions that when executed by the processing resource cause the computing device to:

in response to an empty queue and identification of an inactive status of the queue head, place the separate processing unit in the queue in the fair lock mode.

14. The non-transitory machine-readable storage medium of claim 11 comprising instructions that when executed by the processing resource cause the computing device to:

operate the fair lock mode and unfair lock mode within a virtualized environment.

15. The non-transitory machine-readable storage medium of claim 11 comprising instructions that when executed by the processing resource cause the computing device to:

transfer the separate processing unit from the unfair lock mode to the fair lock mode via placement of the separate processing unit in the queue.