System and method for thread prioritization during lock processing

• US 20040216112A1
• Filed: 04/23/2003
• Published: 10/28/2004
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Dunshea, Andrew, Michel, Dirk, Accapadi, Jos Manuel, Van Fleet, James W.
• Granted Patent: US 7,278,141 B2
• Time in Patent Office: Days
• US Class Current: 718/103
• CPC Class Codes: G06F 9/4881 Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

A system and method is altering the priority of a process, or thread of execution, when the process acquires a software lock. The priority is altered when the lock is acquired and restored when the process releases the lock. Thread priorities can be altered for every lock being managed by the operating system or can selectively be altered. In addition, the amount of alteration can be individually adjusted so that a process that acquires one lock receive a different priority boost than a process that acquires a different lock. Furthermore, a method of tuning a computer system by adjusting lock priority values is provided.

Claims

1. A method for altering a priority of a thread of execution that is being executed by a computer operating system, said method comprising:

receiving a request for a software lock from the thread, wherein the software lock is a data structure used to control access to a shared resource;

determining that the software lock is available;

granting the thread access to the shared resource in response to the determination; and

altering the priority of the thread in conjunction with the granting.

2. The method of claim 1 further comprising:

retrieving a priority change value corresponding to the software lock, wherein the altering includes adjusting the priority by the priority change value.

3. The method of claim 1 further comprising:

receiving a release instruction from the thread;

revoking the access previously granted in response to receiving the release instruction; and

readjusting the priority of the thread in conjunction with the revoking.

4. The method of claim 3 further comprising:

retrieving a priority change value corresponding to the software lock, wherein the altering includes adjusting the priority by the priority change value, and wherein the readjusting includes removing the priority change value from the priority.

5. The method of claim 1 wherein the adjusting further comprises:

applying an algorithm to the priority of the thread, the application resulting in a new priority;

determining a differential value between the priority and the new priority;

storing the differential value; and

readjusting the new priority of the thread by the differential value in response to the thread releasing the software lock.

6. The method of claim 1 further comprising:

initializing a plurality of priority change values prior to receiving the request, each of the priority change values corresponding to a different software lock; and

retrieving the priority change value corresponding to the requested software lock prior to the altering, wherein the altering includes adjusting the priority change value by the retrieved priority change value.

7. The method of claim 6 further comprising:

testing the computer operating system following the initialization of the plurality of priority change values; and

changing one or more of the plurality of priority change values in response to the testing.

8. An information handling system comprising:

one or more processors;

a memory accessible by the processors;

a nonvolatile storage device accessible by the processors;

a computer operating system for controlling the use of the processors, the memory, and the storage device, the computer operating system including one or more software lock data structures used to control access to shared resources;

a software lock tool for altering a priority of a thread of execution that is being executed by the computer operating system, the software lock tool including;

means for altering a priority of a thread of execution that is being executed by a computer operating system, said method comprising;

means for receiving a request for a software lock from the thread, wherein the software lock is a data structure used to control access to a shared resource;

means for determining that the software lock is available;

means for granting the thread access to the shared resource in response to the determination; and

means for altering the priority of the thread in conjunction with the granting.

9. The information handling system of claim 8 further comprising:

means for retrieving a priority change value corresponding to the software lock, wherein the means for altering includes means for adjusting the priority by the priority change value.

10. The information handling system of claim 8 further comprising:

means for receiving a release instruction from the thread;

means for revoking the access previously granted in response to receiving the release instruction; and

means for readjusting the priority of the thread in conjunction with the revoking.

11. The information handling system of claim 10 further comprising:

means for retrieving a priority change value corresponding to the software lock, wherein the altering includes adjusting the priority by the priority change value, and wherein the readjusting includes removing the priority change value from the priority.

12. The information handling system of claim 8 wherein the means for adjusting further comprises:

means for applying an algorithm to the priority of the thread, the application resulting in a new priority;

means for determining a differential value between the priority and the new priority;

means for storing the differential value; and

means for readjusting the new priority of the thread by the differential value in response to the thread releasing the software lock.

13. The information handling system of claim 8 further comprising:

means for initializing a plurality of priority change values prior to receiving the request, each of the priority change values corresponding to a different software lock; and

means for retrieving the priority change value corresponding to the requested software lock prior to the altering, wherein the altering includes adjusting the priority change value by the retrieved priority change value.

14. A computer program product stored in a computer operable media for altering a priority of a thread of execution that is being executed by a computer operating system, said computer program product comprising:

means for receiving a request for a software lock from the thread, wherein the software lock is a data structure used to control access to a shared resource;

means for determining that the software lock is available;

means for granting the thread access to the shared resource in response to the determination; and

means for altering the priority of the thread in conjunction with the granting.

15. The computer program product of claim 14 further comprising:

means for retrieving a priority change value corresponding to the software lock, wherein the means for altering includes means for adjusting the priority by the priority change value.

16. The computer program product of claim 14 further comprising:

means for receiving a release instruction from the thread;

means for revoking the access previously granted in response to receiving the release instruction; and

means for readjusting the priority of the thread in conjunction with the revoking.

17. The computer program product of claim 16 further comprising:

means for retrieving a priority change value corresponding to the software lock, wherein the means for altering includes means for adjusting the priority by the priority change value, and wherein the means for readjusting includes means for removing the priority change value from the priority.

18. The computer program product of claim 14 wherein the adjusting further comprises:

means for applying an algorithm to the priority of the thread, the application resulting in a new priority;

means for determining a differential value between the priority and the new priority;

means for storing the differential value; and

means for readjusting the new priority of the thread by the differential value in response to the thread releasing the software lock.

19. The computer program product of claim 14 further comprising:

means for initializing a plurality of priority change values prior to receiving the request, each of the priority change values corresponding to a different software lock; and

means for retrieving the priority change value corresponding to the requested software lock prior to the altering, wherein the altering includes adjusting the priority change value by the retrieved priority change value.

20. The computer program product of claim 19 further comprising:

means for testing the computer operating system following the initialization of the plurality of priority change values; and

means for changing one or more of the plurality of priority change values in response to the testing.