Adaptive spin latches

• US 6,976,107 B2
• Filed: 09/12/2002
• Issued: 12/13/2005
• Est. Priority Date: 04/15/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hagen, Dale J., Schormann, Stephen A., Huras, Matthew A., Wilding, Mark F., Limoges, Joseph Serge, Evans, Dominique J.
• Primary Examiner(s): Vo, Tim
• Assistant Examiner(s): Knoll, Clifford
• Application Number:
  US10/242,524
• Publication Number:
  US 20030196015A1
• Time in Patent Office: 1,188 Days
• Field of Search: 707/8, 707/9, 707/10, 707/200, 718/102, 718/104
• US Class Current: 710/220
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

An adaptive spin latch system is provided for use in a multiprocessor computer system. The spin latch system includes a run queue, a spin latch module and a wait queue. The run queue is adapted to store agent index data correlated to at least one agent in run mode. The spin latch module is adapted to put the at least one agent into sleep mode for a period of time correlated to a number of agents awaiting access to a resource. The wait queue is adapted to store agent index data correlated to the at least one agent in sleep mode. A method of regulating access by agents to a resource in a multiprocessor computing system is also provided.

Claims

1. An adaptive spin latch system for use in a multiprocessor computer system, the spin latch system comprising:

a run queue adapted to store agent index data correlated to at least one agent in execution;

a spin latch module adapted to put the at least one agent into sleep mode for a period of time multiplied by a number of agents awaiting access to a resource whereby as the number of agents awaiting access increases the amount of time each waiting agent is put into sleep mode correspondingly increases; and

a wait queue adapted to store agent index data correlated to the at least one agent in sleep mode, awaiting access to a resource.

2. The adaptive spin latch system as claimed in claim 1, wherein the spin latch module is adapted to detect if the resource is unavailable for access by the at least one agent in execution mode.

3. The adaptive spin latch system as claimed in claim 2, wherein the spin latch module is operatively coupled to an operating system, and wherein the spin latch module is adapted to cause the deletion of index data in the run queue correlated to the agent in execution mode and cause the storage of index data in the wait queue correlated to the agent.

4. The adaptive spin latch system of claim 1 operatively coupled to a database management system.

5. The adaptive spin latch system as claimed in claim 1, further comprising means for determining the number of agents awaiting access to the resource.

6. The adaptive spin latch system as claimed in claim 2, further comprising a resource waiter counter adapted to store data correlated to the number of agents awaiting access to the resource.

7. A computer program stored on a computer readable medium having executable instructions for directing a computer processing system to implement an adaptive spin latch system, comprising:

a run queue adapted to store agent index data correlated to at least one agent in execution mode;

a spin latch module adapted to put the at least one agent into sleep mode for a period of time multiplied by a number of agents awaiting access to a resource whereby as the number of agents awaiting access increases the amount of time each waiting agent is put into sleep mode correspondingly increases; and

a wait queue adapted to store agent index data correlated to the at least one agent in sleep mode, awaiting access to a resource.

8. A method of regulating access by agents to a resource in a multiprocessor computing system, the method comprising:

providing at least one agent, wherein the at least one agent is capable of being set in at least a run mode and a sleep mode;

determining the number of agents awaiting access to the resource;

determining if the resource is unavailable for access by the at least one agent; and

upon determining that the resource is unavailable for access by the at least one agent, putting the at least one agent into sleep mode for a period of time multiplied by the number of agents awaiting access to the resource whereby as the number of agents awaiting access increases the amount of time each waiting agent is put into sleep mode correspondingly increases.

9. The method as claimed in claim 8, further comprising providing a run queue adapted to store agent index data correlated to at least one agent in run mode and providing a wait queue adapted to store agent index data correlated to the at least one agent in sleep mode, wherein said agent in sleep mode is awaiting access to a resource.

10. The method as claimed in claim 9, wherein said upon determining comprises storing agent index data correlated to the at least one agent in the wait queue, and deleting agent index data correlated to the at least one agent from the run queue.

11. The method as claimed in claim 10, further comprising providing a resource waiter counter adapted to store data correlated to the number of agents awaiting access to the resource.

12. The method as claimed in claim 11, further comprising:

determining the expire of the period of time; and

upon the expire of the period of time, putting the at least one agent into run mode.

13. A computer program product having a computer readable medium having instructions for directing a computer system to perform a method of regulating access by agents to a resource in a multiprocessor computing system, comprising:

providing at least one agent, wherein the at least one agent is capable of being set in at least a run mode and a sleep mode;

determining the number of agents awaiting access to the resource;

determining if the resource is unavailable for access by the at least one agent;

upon determining that the resource is unavailable for access by the at least one agent, puffing the at least one agent into sleep made for a period of time multiplied by the number of agents awaiting access to the resource whereby as the number of agents awaiting access increases the amount of time each waiting agent is put into sleep mode correspondingly increases; and

upon the expire of the period of time, putting the at least one agent into run mode.