Stream management in a multithreaded environment

• US 20040093603A1
• Filed: 09/16/2003
• Published: 05/13/2004
• Est. Priority Date: 11/13/1998
• Status: Active Grant

• Current Assignee: CRAY Incorporated (Hewlett-Packard Enterprise Company)
• Original Assignee: CRAY Incorporated (Hewlett-Packard Enterprise Company)
• Inventors: Alverson, Gail A., Koblenz, Brian D., Smith, Burton J., Callahan, Charles David II, Korry, Richard D., Coatney, Susan L.
• Granted Patent: US 7,191,444 B2
• Time in Patent Office: Days
• US Class Current: 718/107
• CPC Class Codes: G06F 2209/481 Exception handling
• CPC Class Codes: G06F 9/461 Saving or restoring of program or task context
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: G06F 9/485 Task life-cycle, e.g. stopping, restarting, resuming execution G06F9/4881 takes precedence
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A method and system that prepares a task for being swapped out from processor utilization that is executing on a computer with multiple processors that each support multiple streams. The task has one or more teams of threads, where each team represents threads executing on a single processor. The task designates, for each stream that is executing a thread, one stream as a team master stream and one stream as a task master stream. For each team master stream, the task notifies the operating system that the team is ready to be swapped out when each other thread of the team has saved its state and has quit its stream. Finally, for the task master stream, the task notifies the operating system that the task is ready to be swapped when it has saved its state and each other team has notified that it is ready to be swapped out.

Claims

1. A method in a computer system for returning a stream to a task executing an operating system call that is blocked, the computer system having a processor with multiple streams, the method comprising:

under control of the operating system executing on a stream, invoking a function provided by the task;

under control of the invoked function, executing instructions of the task on that stream; and

under control of the operating system, notifying the task when the operating system call is complete.

2. The method of claim 1 wherein the notifying includes

invoking a function provided by the task using a stream of the operating system;

and

under control of that invoked function,

indicating that the operating system call is complete; and

invoking another operating system call to return the operating system stream to the operating system.

3. The method of claim 1 wherein the executing of instructions on that stream includes

indicating that a thread that invoked the operating system call is blocked;

and

executing another thread on that stream.

4. A system for returning a stream to a task executing an operating system call that is blocked, the system having a processor with multiple streams and comprising:

a component that, under control of the operating system executing on a stream, invokes a function provided by the task;

a component that, under control of the invoked function, executes instructions of the task on that stream; and

a component that, under control of the operating system, notifies the task when the operating system call is complete.

5. The system of claim 4 wherein the notification includes

invoking a function provided by the task using a stream of the operating system;

and

under control of that invoked function,

indicating that the operating system call is complete; and

invoking another operating system call to return the operating system stream to the operating system.

6. The system of claim 4 wherein the instructions of the test on that stream include

an indication that a thread that invoked the operating system call is blocked;

and

execution of another thread on that stream.

7. A method in a computer system for assigning a processor resource to a thread of a task, the method comprising:

under control of a thread of the task, invoking an operating system call that will block and wait for the occurrence of an event; and

under control of the operating system, when the call is blocked, invoking a routine of the task so that the routine can assign the processor resource to another thread of the task.

8. The method of claim 7 wherein the processor resource is a stream of a processor that supports multiple streams.

9. The method of claim 7 wherein the task registers the routine with the operating prior to invoking the operating system call.

10. The method of claim 7 including notifying the task when a operating system call completes.

11. A system for assigning a processor resource to a thread of a task, the system comprising:

a component for under control of a thread of the task, invoking an operating system call that will block and wait for the occurrence of an event; and

a component for, under control of the operating system, invoking a routine of the task so that the routine can assign the processor resource to another thread of the task.

12. The system of claim 11 wherein the processor resource is a stream of a processor that supports multiple streams.

13. The system of claim 11 wherein the task registers the routine with the operating prior to invoking the operating system call.

14. The system of claim 11 including notifying the task when a operating system call completes.

15. A method in a computer system for returning a stream to a user program, the computer system having an operating system, the method comprising:

under control of the operating system,

when an operating system call in a stream will block, invoking a first function of a task that will return the stream to the task; and

when the operating system call becomes unblocked, invoking a second function of the task.

16. The method of claim 15 wherein the operating system invokes the first function using the stream that will block.

17. The method of claim 16 wherein invoking the first function returns the stream to the user program.

18. The method of claim 17 wherein the user program selects a thread that is not blocked for execution on the stream.

19. The method of claim 15 wherein the second function schedules for restarting a thread that was blocked on the operating system call that was blocked.

20. The method of claim 15 wherein the second function returns a stream provided by the operating system.

21. A method in a computer system for returning a stream to a user program, the computer system having an operating system, the method comprising:

under control of the user program, invoking an operating system call;

executing the operating system call in a user stream of the user program; and

under control of the operating system, when the operating system call will block,

when a thread making the operating system call is locked, waiting for the operating system call to become unblocked; and

when a thread making the operating system call is not locked,

invoking a first function of the user program that will return the stream to the task;

under control of a trap handler routine, placing the thread in a blocked pool and selecting another thread to execute on the stream; and

when the operating system call becomes unblocked, invoking a second function of the user program in a stream of the operating system.

22. The method of claim 21 wherein the second function schedules for restarting a thread that was blocked on the operating system call that was blocked.

23. The method of claim 21 wherein the second function returns a stream provided by the operating system.