Task management system

• US 7,302,686 B2
• Filed: 07/03/2002
• Issued: 11/27/2007
• Est. Priority Date: 07/04/2001
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Togawa, Atsushi
• Primary Examiner(s): An; Meng-Al T.
• Assistant Examiner(s): To; Jennifer N.
• Application Number:
  US10/190,203
• Publication Number:
  US 20030014463A1
• Time in Patent Office: 1,973 Days
• Field of Search: 718100-108, 711/151, 709223-225, 709/203, 710240-244
• US Class Current: 718/103
• CPC Class Codes: G06F 9/4887 involving deadlines, e.g. rate based, periodic

Abstract

A task management system that inherit priority and that can reduce the queue operation required for transition to/return from a mutual exclusion awaiting state The task management system can execute a task without considering its priority, start or stop a server task and inherit priority without operating the dispatch queue. The task management system includes activity retaining information, context retaining information, and a dispatch queue used to select the highest priority task. Information on a task is divided and managed by the activity and the context, where each activity is inserted into/deleted from the dispatch queue. When the priority of a task is inherited by another task, only the correspondence between activity and context is changed.

Claims

1. A task management system using a single processor to manage tasks, said task management system comprising:

first data retaining means for retaining first data information related to scheduling of the managed tasks which is included in information on arbitrary tasks;

second data retaining means for retaining second data information which is not recorded in said first data;

a dispatch queue for selecting the highest priority task from among executable tasks;

a mutex awaiting queue for recording a task waiting for an owner of a mutex which is a mutual exclusion of tasks; and

a possession object queue for recording said mutex possessed by said tasks,

wherein information on one task is divisionally managed by said first data and said second data,

wherein said first data is used as data to be inserted into or deleted from said dispatch queue, and

when priority inheritance from one task to another task is performed using said dispatch queue, said mutex awaiting queue and said possession object queue, only the correspondence between said first data and said second data is changed,

wherein the mutex awaiting queue is formed as a bidirectional link list comprising an acquirement request class as an element.

2. A task management system according to claim 1, when task execution must be stopped based on one condition variable for performing the priority inheritance, an operation for said dispatch queue is delayed until the time said task execution must be stopped based on another condition variable without immediately performing the operation for said dispatch queue.

3. A task management system using a single processor to manage tasks, said task management system comprising:

first data retaining means for retaining first data information related to scheduling of the managed tasks which is included in information on arbitrary tasks;

second data retaining means for retaining second data information which is not recorded in said first data;

a dispatch queue for selecting the highest priority task from among executable tasks;

a server task in one module which is started by a service request from a task operating in another module and which processes said service request;

a client task for issuing a service request to said server task; and

a service awaiting queue for recording a service request waiting for processing,

wherein information on one task is divisionally managed by said first data and said second data,

wherein said first data is used as data to be inserted into or deleted from said dispatch queue,

wherein said server task is a particular task having no first data thereof,

wherein when said server task and said client task are started or terminated, and when priority inheritance for said server task and said client task is performed, using said dispatch queue and said service awaiting queue, only the correspondence between said first data and said second data is changed,

wherein the inutex awaiting queue is formed as a bidirectional link list comprising an acquirement request class as an element.

4. A task management system according to claim 3, when said client task stops to await the service request from said server task, an operation for said dispatch queue is delayed until the time said task management system finds that said client task is mistakenly selected from said dispatch queue without immediately deleting said client task from said dispatch queue.