Scheduling operations called by a task on a real-time or non-real-time processor

• US 20070083871A1
• Filed: 09/08/2005
• Published: 04/12/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: X Corp. (f/k/a Twitter, Inc.) (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: McKenney, Paul
• Granted Patent: US 7,734,833 B2
• Time in Patent Office: Days
• US Class Current: 718/105
• CPC Class Codes: G06F 2209/506 Constraint
• CPC Class Codes: G06F 9/4887 involving deadlines, e.g. rate based, periodic
• CPC Class Codes: G06F 9/5038 considering the execution order of a plurality of tasks, e.g. taking priority or time dependency constraints into consideration scheduling strategies G06F9/4881 and subgroups

Abstract

Provided is a method, system, and program for scheduling operations called by a task on a real-time or non-real-time processor. Execution durations are provided for operations. A call is received from a task for an operation. A determination is made of a latency requirement for a first processor and of the execution duration of the called operation. The called operation is executed on the first processor in response to determining that the determined execution duration is less than the latency requirement. The called operation is executed on a second processor in response to determining that the determined execution duration is greater than the latency requirement.

Claims

1. An article of manufacture including code executed to perform operations to schedule tasks between a first processor and a second processor, the operations comprising:

providing execution durations for operations;

receiving a call from a task for an operation;

determining a latency requirement for the first processor;

determining the execution duration of the called operation;

executing the called operation on the first processor in response to determining that the determined execution duration is less than the latency requirement; and

executing the called operation on the second processor in response to determining that the determined execution duration is greater than the latency requirement.

2. The article of manufacture of claim 1, wherein transferring execution of a task from one processor comprising one of the first and second processors to another processor comprising one of the first and second processor further comprises placing the task in a shared queue to be transferred from one processor to another.

3. The article of manufacture of claim 1, wherein determining the latency requirement comprises:

providing delay tolerances for a set of tasks indicating a time within which execution of the task must begin in response to being called; and

determining a minimum delay tolerance for the set of tasks, wherein the determined latency requirement comprises the determined minimum delay tolerance.

4. The article of manufacture of claim 3, wherein tasks may be of a first type or a second type, wherein tasks of the first type are assigned to the first processor to execute and wherein tasks of the second type are assigned to the second processor to execute, wherein the set of tasks for which delay tolerances are provided comprises the first type of tasks.

5. The article of manufacture of claim 4, wherein tasks of the first type have a higher execution priority over tasks of the second type.

6. The article of manufacture of claim 4, wherein the first type of task is deterministic and wherein the second type of task is non-deterministic.

7. The article of manufacture of claim 1, wherein the latency requirement is a maximum delay time during which execution of tasks assigned to the first processor must begin.

8. The article of manufacture of claim 1, wherein each task is executed on a thread in the operating system, wherein each task invokes multiple operations, and wherein the operations invoked by the tasks are members of a set of operations comprising system calls, interrupts, and exceptions.

9. The article of manufacture of claim 1, wherein the latency requirement comprises a first latency requirement associated with the first processor and wherein a second latency requirement is associated with a third processor and is greater than the first latency requirement, wherein the task is executing on the first processor when the call for the operation is received, and wherein the operations further comprise:

determining whether the determined execution duration is less than the second latency requirement in response to determining that the determined execution duration is greater than the first latency requirement; and

executing the called operation on the third processor in response to determining that the determined execution duration is less than the second latency requirement, wherein the called operation is executed on the second processor in response to determining that the determined execution duration is greater than both the first and second latency requirements.

10. An article of manufacture including code executed to perform operations to schedule tasks between a first processor and a second processor, the operations comprising:

providing execution durations for operations;

receiving a call from a task for an operation;

determining a latency requirement for the first processor;

determining the execution duration of the called operation;

determining whether the called operation is deterministic or non-deterministic;

executing the called operation on the first processor in response to determining that the operation is deterministic and that the determined execution duration is less than the latency requirement; and

executing the operation on the second processor in response to determining that the operation is non-deterministic or that the operation is deterministic and that the execution duration is greater than the latency requirement.

11. The article of manufacture of claim 10, wherein the task is executing on the first processor, and wherein the operations further comprise:

transferring the task to the second processor to execute the called operation in response to determining that the operation is to be executed on the second processor; and

transferring the task to the first processor to continue executing the task in response to the second processor completing execution of the called operation.

12. A system, comprising:

a first processor;

a second processor;

a memory; and

an operating system executed in the memory to perform operations, the operations comprising;

providing execution durations for operations;

receiving a call from a task for an operation;

determining a latency requirement for the first processor;

determining the execution duration of the called operation;

executing the called operation on the first processor in response to determining that the determined execution duration is less than the latency requirement; and

executing the called operation on the second processor in response to determining that the determined execution duration is greater than the latency requirement.

13. The system of claim 12, wherein the operations further comprise:

determining whether the called operation is deterministic or non-deterministic; and

executing the operation on the second processor in response to determining that the operation is of the non-deterministic or that the operation is of deterministic type and that the execution duration is greater than the latency requirement, wherein the operation is executed on the first processor in response to determining that the operation is deterministic and that the determined execution duration is less than the latency requirement.

14. A system, comprising:

a first processor;

a second processor;

a third processor;

a memory;

an operating system executed in the memory to perform operations, the operations comprising;

providing execution durations for operations;

receiving a call from a task for an operation;

determining a first latency requirement for the first processor, wherein a second latency requirement is associated with the third processor and is greater than the first latency requirement,;

determining the execution duration of the called operation;

executing the called operation on the first processor in response to determining that the determined execution duration is less than the latency requirement;

executing the called operation on the second processor in response to determining that the determined execution duration is greater than the latency requirement;

determining whether the determined execution duration is less than the second latency requirement in response to determining that the determined execution duration is greater than the first latency requirement; and

executing the called operation on the third processor in response to determining that the determined execution duration is less than the second latency requirement, wherein the called operation is executed on the second processor in response to determining that the determined execution duration is greater than both the first and second latency requirements.

15. A method, comprising:

providing execution durations for operations;

receiving a call from a task for an operation;

determining a latency requirement for a first processor;

determining the execution duration of the called operation;

executing the called operation on the first processor in response to determining that the determined execution duration is less than the latency requirement; and

executing the called operation on a second processor in response to determining that the determined execution duration is greater than the latency requirement.

16. The method of claim 15, further comprising:

determining whether the called operation is deterministic or non-deterministic; and

executing the operation on the second processor in response to determining that the operation is of the non-deterministic or that the operation is of deterministic type and that the execution duration is greater than the latency requirement, wherein the operation is executed on the first processor in response to determining that the operation is deterministic and that the determined execution duration is less than the latency requirement.

17. The method of claim 16, wherein the task is executing on the first processor, further comprising:

transferring the task to the second processor to execute the called operation in response to determining that the operation is to be executed on the second processor; and

transferring the task to the first processor to continue executing the task in response to the second processor completing execution of the called operation.

18. The method of claim 15, wherein determining the latency requirement comprises:

providing delay tolerances for a set of tasks indicating a time within which execution of the task must begin in response to being called; and

determining a minimum delay tolerance for the set of tasks, wherein the determined latency requirement comprises the determined minimum delay tolerance.

19. The method of claim 18, wherein tasks may be of a first type or a second type, wherein tasks of the first type are assigned to the first processor to execute and wherein tasks of the second type are assigned to the second processor to execute, wherein the set of tasks for which delay tolerances are provided comprises the first type of tasks.

20. The method of claim 15, wherein the latency requirement is a maximum delay time during which execution of tasks assigned to the first processor must begin.