JP2000122883A - Task managing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve service quality by discriminatingly managing a repetitive execution task which is changeable in service quality and re-executing the repetitive execution time in an excessive task execution allocation time when the excessive time is available at the time of task switching. SOLUTION: A task which performs a process for input to an input device and a process for output to an output device 107 is recorded in a storage device 103. An accepting process performed by a task acceptance part 110 is started when a request to set a cycle set previously for the task and a process time is made. The execution of a service quality task registered in a task management table 112 is checked by a task which has a short cycle at the time of task switching and when a task reaching the start time of the cycle is found, the task is executed until the process time of the task is consumed. Here, when a task having a shorter cycle than the task reaches the start time of the cycle during the task execution, the execution of the task is interrupted and the task having the shorter cycle is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a task management method, and more particularly to a task management method for controlling service quality of an application by controlling execution of a task.

[0002]

2. Description of the Related Art Generally, in a communication terminal that transmits and receives real-time information such as moving images and audios, it is necessary to perform tasks such as reception, display, and transmission of such information in parallel in real time. By switching and executing these tasks using a multitask system, various applications are provided. In such a multitask system, it is necessary to control the quality of service of an application by reliably assigning a predetermined processing time to each task at a predetermined cycle and executing the task.

[0003] The service quality of an application is required individually when each application is executed. For example, an application for transferring image data corresponds to the number of screen frames that can be transferred per unit time, the resolution of screen data, and the like, and when transferring audio data, it corresponds to the sound quality of reproduced sound. Therefore, in the multitask system, the processing time is controlled to be allocated to the task of each application so as to reliably provide the individually requested service quality.

Conventionally, as a task management method for controlling the service quality of an application by controlling the execution of a task, when a new task is reserved, a new task and all reserved tasks are requested separately. A task management method that performs tasks that require periodic execution and guarantees of delay from the time of execution by determining whether or not the service can be executed with the specified service quality and accepting new tasks only when the It has been proposed (see, for example, JP-A-10-171667).

[0005]

However, such a conventional task management method judges whether or not the task can be executed by a reservation process before executing the task, and only when the service quality control can be surely performed for all tasks, The task was accepted and the task was executed. This is because the service quality task executed in the multitask system is composed of tasks in which the requested service quality is fixed, that is, a single execution task in which each task is executed only once in the cycle, Further, it is assumed that the processing time required for each task at the maximum load is set as the processing time required for each task.

[0006] Therefore, it is not possible to cope with a task whose service quality is variable. For example, when a certain service quality is secured and the processing time of another task is left, the task of the task whose service quality is variable cannot be performed. There is a problem that the service quality cannot be improved by allocating the processing time.

For example, when a user wants to check video data while downloading the video data from a video-on-demand system connected to a network, the service quality that can be ensured for the task of displaying video data is low. If set,
Even when the download load is lighter than the set value and the allocated time is left, the service quality cannot be improved by allocating the remaining allocated time to the video data display task.

The present invention has been made to solve such a problem, and while maintaining a predetermined service quality, the service quality is allocated to a task having a variable service quality when there is an extra task assignment time. It aims to provide a task management method that can be enhanced.

[0009]

In order to achieve the above object, a task management method according to the present invention includes a service quality task in addition to the task management method described in Japanese Patent Laid-Open No. Hei 10-171667. Among them, the duplication execution task whose service quality is variable is distinguished and managed, and when the task execution assignment time is left at the time of task switching, the duplication execution task is re-executed in the surplus time.

More specifically, as service quality tasks requiring service quality control, there are provided a single execution task that is executed only once in the cycle and a duplicate execution task that can be executed a plurality of times in the cycle. When a task is reserved, set which task is set in the task management table. At the time of task switching, if there are single tasks and duplicate tasks that have not been executed within each cycle, select these tasks. If these tasks do not exist, it is determined that the task execution allotted time is left, and one of the duplicately executed tasks is selected and re-executed in the surplus time.

[0011]

Next, the present invention will be described with reference to the drawings. In the present invention, among tasks switched and controlled by the multitask system, a task requiring service quality control is called a service quality task, and a task not requiring service quality control is called a normal task. Also, among the service quality tasks, a task that requires a fixed service quality and is executed only once within the cycle is called a single execution task. Apart from this, the required service quality is variable. A task that can be executed a plurality of times in that cycle is called a duplicate execution task.

FIG. 1 is a block diagram of a multitask system used in a task management method according to an embodiment of the present invention. The multitask system 100 includes a CPU 101,
Timer 102, storage device 103 such as a hard disk device, memory 105, input device 106 such as a keyboard or mouse, and output device 107 such as a display
It has.

The CPU 101, timer 102, storage device 103, memory 105, input device 106, and output device 107 are interconnected by a bus 104. Timer 1
02 has a function of interrupting the CPU 101 at each set time, and it is possible to notify the CPU 101 of the elapse of the set time by this interrupt. Storage device 1
In 03, a task program and the like are recorded, and are read out to the memory 105 as needed.

The tasks of performing input processing for the input device 106 and output processing for the output device 107 are also recorded in the storage device 103, and are stored in the memory 105 as necessary.
Is read and executed. A task receiving unit 110 in which a task receiving program for causing the CPU 101 to execute a task receiving process described later is stored on the memory 105.
And a task execution unit 111 that stores a task execution program for causing the CPU 101 to execute the task.

The memory 105 has a task management table 112 for recording information on tasks necessary for realizing the multitask system, and is used when accepting and executing tasks. FIG. 2 is an explanatory diagram showing an example of the configuration of the task management table 112. The task management table 112 includes storage areas for task identifiers 201, task information 202, and service quality task management information 203 for the number of manageable tasks.

The task identifier 201 is used to distinguish each task. The task information 202 is for storing information necessary for task management in a normal multitask system. The task identifier 201 and the task information 202 are often used in a normal multitask system. The service quality task management information 203 is newly provided in the present invention.

FIG. 3 shows service quality task management information 203.
FIG. 4 is an explanatory diagram showing an example of the configuration of FIG. Task type 301
Is for indicating the type of service quality task. Here, after the processing time specified by the processing time 304 is assigned to the task and executed, the task is a task that can execute the same task again within the same cycle specified by the cycle 302, that is, a task that is a duplicate execution task. Used to indicate that

The cycle 302 is for recording a set value when the cycle is set for the task. The cycle counter 303 records the elapsed time of the cycle when executing a task in which the cycle and the processing time are set. The processing time 304 is for recording a set value when the processing time for the task is set.

The processing time counter 305 is used to record the time during which the task is executed. The re-execution counter 306 is for recording the number of times the same task is re-executed within the cycle specified by the cycle 302 after the processing time specified by the processing time 304 is assigned to the task for the duplicate execution task. It is.

Hereinafter, the task receiving process of the present invention will be described with reference to FIG. FIG. 4 is a flowchart showing an example of an operation for receiving a service quality task when the present invention is used. The reception process of the service quality task in which the cycle and the processing time are set is performed by the task reception unit 110. This reception processing is started when a request for setting a cycle and a processing time set in advance (or designated by the user) for the task occurs (step 40).
1).

Next, the cycle and the processing time are set for the task, and it is determined whether the processing time can be allocated to the set cycle for each task, and it is determined whether the request can be accepted (step 402). . The determination method is as follows: For tasks for which the cycle and processing time have already been set and for tasks for which new setting has been requested, it is determined that the processing time can be assigned to each task if the following conditions are satisfied. Accept.

Condition: n tasks (n is an integer of 2 or more) are rearranged in the order of shortest cycle, and the i-th task (i is 1 ≦ i <
n), the period of the task i is Fi,
When the processing time per cycle is Pi, and the remainder obtained by dividing X by Y is expressed as mod (X / Y), when mod (Fn / Fi) = 0, Ri = Fn / Fi mod (Fn / Fi) ) ≠ 0, Ri = Fn / Fi +
1 Fn-Pn> Σ (RixPi) (where 1 ≦ i <n)

This corresponds to the cycle F of the task n having the longest cycle.
n, the product of the number of executions Ri of the task i having a shorter cycle than the task n and the processing time Pi of the task i (Ri
XPi) indicates a condition that the sum total of the tasks n is shorter than the idle time (Fn-Pn) in the cycle Fn of the task n. Therefore, by satisfying this condition, it becomes possible to allocate an execution time to all the tasks in the cycle of each task by the processing time.

If the request is not accepted (step 402: N0), the value is returned as acceptance failure (step 403), and the process is terminated (step 408). If the request is accepted (step 402: YE
S), the cycle and the processing time set for the task for which the request has been accepted are set to the cycle 302 and the processing time 3 of the service quality task management information 203 corresponding to the task identifier of this task.
04, and the task type 301 is registered as a service quality task (step 404).

Further, if the task is designated to have variable service quality (step 405: YE
S), the task type 301 of this task is registered as a duplication execution task (step 406), a value is returned as success reception (step 407), and the process ends (step 40).
8). In the case of a single execution task whose service quality is not variable (step 405: N0), a value is returned as success of reception (step 407), and the process ends (step 40).
8).

As described above, the task management table 11
The execution of the service quality task registered in 2 is checked starting from the task with the shortest cycle when the task is switched, and if a task having the cycle start time is found, the task is executed until the processing time of the task is consumed. Here, if the start time of the cycle of the task having a shorter cycle than the task is reached during the task execution, the execution of the task is interrupted and the task with the shorter cycle is executed.

When all the tasks accepted as service quality tasks consume a predetermined processing time, the duplicate execution task is executed until the start time of the next cycle of any task. As a result, among the service quality tasks, the service quality required by the single execution task can be accurately provided, and the better service quality can be provided for the duplicate execution task.

FIG. 5 is a flowchart showing an example of a processing operation at the time of task switching when the present invention is used. The task switching is performed at every task switching unit time set in the multitask system or at the end of each task (step 501). First, the cycle counters 303 of all the service quality tasks for which the cycle and the processing time are set are updated based on the time elapsed since the previous task switching.

Subsequently, if the task executed immediately before is a service quality task (step 503: YE
S), the processing time counter 305 of the task is updated (step 504). Next, if there is a service quality task whose cycle counter 303 has reached the cycle 302 (step 505: YES), the cycle counter 30 of that task
3, processing time counter 305, and re-execution counter 3
06 are reset (step 506).

Then, it is detected whether there is an operable single execution task and a duplicate execution task that have not been executed within the cycle (step 507). In this case, the task is examined starting from the task with the shortest cycle. If a task whose processing time counter 305 is smaller than the processing time 304 is found, the task is set as the next operation task.

If the processing time counter 305 finds no task smaller than the processing time 304, it is determined that there is no next operable service quality task. Therefore, in step 503, when there is a task to be operated next (step 507: YE
S), the task is switched to that task (step 508), and the task switching is completed (step 5).
09).

On the other hand, when there is no task to be operated next (step 503: NO), it is determined that the task execution allocation time is left, and it is determined whether there is a re-executable duplicate execution task (step 510). ). Here, the task type 301 of each quality service task is checked whether there is a duplicate execution task, and if there is no task type 301 indicating a duplicate execution task, the determination in step 510 is set to N0.

In step 510, if there are a plurality of overlapping execution tasks, the re-execution counters 306 are checked. If each of the re-execution counters 306 has reached a predetermined number, the judgment in step 510 is made. NO. As a result, the surplus time of the task execution allocation time is not used by the duplication execution task, and the processing time is allocated to the normal task that does not need the quality service control, and the normal task does not move at all. Can be avoided.

Therefore, if step 510: NO, an existing task switching process is performed to execute a normal task (step 511), and the task switching process ends (step 509). In a case where the normal task may not be moved at all, if there is a task with a variable service quality, the determination of step 510 is always YES.
It may be.

On the other hand, if step 510: YES,
Switch task execution to duplicate execution task (Step 5
12), end the process (step 509). In this case, if there is one duplicate execution task, the task is switched to that task. In addition, when there are a plurality of duplicate execution tasks, in order to equalize the task assignment, first, from the duplicate execution tasks, select the task with the shortest cycle and the earliest registration, and record the task identifier, From the next time on, tasks are switched in order of short cycle and registration order, and tasks are switched.

When there are a plurality of duplicate execution tasks, the re-execution counter 306 may be checked, and the re-execution task having the smaller number of re-executions may be preferentially selected and executed. As a result, it is possible to suppress a bias in the number of executions among the duplication tasks, and to execute the tasks equally.

As described above, at the time of task switching, if there are operable single-execution tasks and duplicate-execution tasks that have not been executed in each cycle, the tasks are executed based on the cycle and the processing time. If there are no operable single-execution tasks and duplicate execution tasks that have not yet been executed within the cycle and the task execution allocation time has been left, the duplicate execution task is re-executed. The performed service quality control is executed accurately, and the execution amount of the duplicate execution task can be increased by using the surplus time.

[0038]

As described above, according to the present invention, in the execution of a task whose service quality is variable, the service quality can be improved by utilizing the surplus time during which the task whose period and processing time are set is not executed. Re-executing variable overlapping execution tasks increases the task allocation opportunities for tasks with variable service quality without hindering the execution of service quality tasks with a set period and processing time, resulting in higher service quality. The service quality of the variable task can be improved, and the surplus time of task assignment can be effectively used.

[Brief description of the drawings]

FIG. 1 is a block diagram of a multitask system to which a task management method according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram illustrating an example of a configuration of a task management table.

FIG. 3 is an explanatory diagram illustrating an example of a configuration of service quality task management information.

FIG. 4 is a flowchart illustrating an example of a receiving operation for setting a cycle and a processing time.

FIG. 5 is a flowchart illustrating an example of a processing operation at the time of task switching.

[Explanation of symbols]

100: Multitask system, 101: CPU, 10
2: timer, 103: recording device, 104: bus, 105
... memory, 106 ... input device, 107 ... output device, 11
0: task reception unit, 111: task execution unit, 112: task management table, 201: task identifier, 202: task information, 203: service quality task management information, 30
1: Task type, 302: Period, 303: Period counter, 304: Processing time, 305: Processing time counter, 3
06 ... Re-execution counter.

Claims (4)

[Claims] 1. Among a plurality of tasks switched and controlled by a multitask system, for a task that requires service quality control, a cycle for executing the task, and a processing time available for executing the task within one cycle In a task management method that controls service quality of tasks by managing the execution of each task based on these cycles and processing time, the task management table manages A single execution task that is executed only once within a task and a duplicate execution task that can be executed multiple times within the cycle are provided. When each task is reserved, which task is set in the task management table, , If there are single and duplicate tasks that have not yet been executed in each cycle,
If these tasks are selected and executed, and these tasks do not exist, it is determined that the task execution allotted time is left, and it is determined that one of the duplicate execution tasks is selected and re-executed in the surplus time. A featured task management method. 2. The task management method according to claim 1, wherein when re-executing the duplicate execution task, a processing time shorter than a remaining time until the start of execution of a single task to be executed next among the duplicate execution tasks. A task management method characterized by selecting and re-executing a duplicate execution task having the following. 3. The task management method according to claim 1, wherein the number of re-executions in the cycle is managed in a task management table for each of the duplicate execution tasks. A task management method characterized in that, when the number of re-executions of an execution task has reached a predetermined number, a re-execution of the duplicate execution task is not performed, and a normal task that does not require service quality control is executed in the remaining time. 4. The task management method according to claim 1, wherein the number of re-executions in the cycle is managed in a task management table for each of the duplication tasks, and when the duplication task is re-executed, the re-execution is performed. A task management method, wherein a task is selected and executed in order from a duplication execution task having a small number of times.