Method and apparatus for handling threads in a data processing system

• US 20040060049A1
• Filed: 09/19/2002
• Published: 03/25/2004
• Est. Priority Date: 09/19/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Schopp, Joel Howard, Mendoza, Alfredo V.
• Granted Patent: US 7,275,247 B2
• Time in Patent Office: Days
• US Class Current: 718/100
• CPC Class Codes: G06F 9/485 Task life-cycle, e.g. stopping, restarting, resuming execution G06F9/4881 takes precedence

Abstract

A method, apparatus, and computer instructions for managing threads. A kernel thread associated with a user thread is detected as being unneeded by the user thread. The kernel thread is semi-detached in which data for the thread does not change stacks in response to the kernel thread being unneeded.

Claims

1. A method in a data processing system for managing threads, the method comprising:

detecting a kernel thread associated with a user thread as being unneeded by the user thread; and

responsive to the kernel thread being unneeded, semi-detaching the kernel thread, wherein data for the thread does not change stacks.

2. The method of claim 1 further comprising:

placing the kernel thread on a semi-detached list; and

placing the kernel thread in an unrunnable state concurrent with the user thread.

3. The method of claim 2 further comprising:

responsive to the user thread waking from sleep, removing the kernel thread from the semi-detached list, wherein reattachment to the user thread is unnecessary.

4. The method of claim 1, wherein the threads execute in a AIX operating system.

5. The method of claim 1, wherein data for the kernel thread remains on a user stack without requiring copying of the data to a kernel stack to semi-detach the kernel thread.

6. The method of claim 1, wherein the detecting and semi-detaching steps are performed using a library.

7. The method of claim 2 further comprising:

responsive to the user thread waking from the sleep state, determining whether a second kernel thread is detached rather than semi-detached; and

responsive to the second kernel thread being detached, attaching the second kernel thread to the user thread.

8. The method of claim 2, wherein the unrunnable state is one of a waiting state or a sleeping state.

9. A data processing system for managing threads, the data processing system comprising:

a bus system;

a communications unit connected to the bus system;

a memory connected to the bus system, wherein the memory includes a set of instructions; and

a processing unit connected to the bus system, wherein the processing unit executes the set of instructions to detect a kernel thread associated with a user thread as being unneeded by the user thread; and

semi-detach the kernel thread in which data for the thread does not change stacks in response to the kernel thread being unneeded.

10. A data processing system for managing threads, the data processing system comprising:

detecting means for detecting a kernel thread associated with a user thread as being unneeded by the user thread; and

semi-detaching means, responsive to the kernel thread being unneeded, for semi-detaching the kernel thread, wherein data for the thread does not change stacks.

11. The data processing system of claim 10 further comprising:

first placing means for placing the kernel thread on a semi-detached list; and

second placing means for placing the kernel thread in an unrunnable state concurrent with the user thread.

12. The data processing system of claim 11 further comprising:

removing means, responsive to the user thread waking from sleep, for removing the kernel thread from the semi-detached list, wherein reattachment to the user thread is unnecessary.

13. The data processing system of claim 10, wherein the threads execute in a AIX operating system.

14. The data processing system of claim 10, wherein data for the kernel thread remains on a user stack without requiring copying of the data to a kernel stack to semi-detach the kernel thread.

15. The data processing system of claim 10, wherein the detecting and semi-detaching steps are performed using a library.

16. The data processing system of claim 11 further comprising:

determining means, responsive to the user thread waking from the sleep state, for determining whether a second kernel thread is detached rather than semi-detached; and

attaching means, responsive to the second kernel thread being detached, for attaching the second kernel thread to the user thread.

17. The data processing system of claim 11, wherein the unrunnable state is one of a waiting state or a sleeping state.

18. A computer program product in a computer readable medium for managing threads, the computer program product comprising:

first instructions for detecting a kernel thread associated with a user thread as being unneeded by the user thread; and

second instructions for responsive to the kernel thread being unneeded, semi-detaching the kernel thread, wherein data for the thread does not change stacks.