JPH0417034A - Task scheduling device - Google Patents

Abstract

PURPOSE:To prevent the priority of a task performing a man-machine interface process from being lowered so as to prevent frequent interruption of a picture drawing process, etc., by providing a man-machine interface processing history storing means and task managing means. CONSTITUTION:A priority storing means 101 which stores the priority of each task, status transition information storing means 102 which stores status transition information indicating transition statuses, and man-machine interface processing history storing means 103 which stores the executing history of the man-machine interface process of each task are provided. In addition, a task managing means 104 which decides whether each task is to be set to an executing status or executable status whenever each task is transferred to a waiting status at a prescribed time or in an executing status and, when a task is transferred to the waiting status, raises the priority of the task is provided. The means 104, on the other hand, lowers the priority only when the extent of the man-machine interface process of the task is small. Therefore, efficient task scheduling can be performed without spoiling the responsiveness to the operation of the operator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a task scheduling device applied to a multitasking computer system that selectively executes a plurality of tasks.

In order to make effective use of the Disaster Natsashimori Computer, there is a multi-task computer system that selectively executes multiple tasks. This type of system is equipped with a task scheduling device that determines which tasks are to be placed in an execution state.

A conventional task scheduling device has a configuration as shown in FIG. 4, for example. In the figure, 401 is a priority storage means for storing the priority of each task;
402 is a state transition information storage means for storing state transition information indicating the state transition of each task; 403 is a state transition information storage means for storing state transition information indicating the state transition of each task; 403 is a state transition information storage means for storing state transition information indicating the state transition of each task; , and state transition information, the task management means determines whether each task is placed in an execution state or an executable state, and also determines the priority of each task.

The state transition information stored in the state transition information storage means 402 indicates the state transition of each task, such as whether the task is in a running state, an executable state, or a waiting state. .

The execution state is a state in which the task is being executed by the CPU 400, and the executable state is a state in which the execution is forcibly interrupted by the periodic operation of the task management means 403 and is waiting for it to be executed again. In addition, the wait state is a state in which the CPU is waiting for the completion of an event, such as waiting for the completion of an operation of a peripheral device in response to an input/output request made in the execution state.
The execution state is canceled by issuing a request to abandon execution by the PU 400, and the process is in a state where it is waiting for the conditions to become executable to be satisfied.

The task management unit 403 selects a task from among tasks in a running state or an executable state to a running state based on the task priority and state transition information at predetermined time intervals and each time a task in a running state becomes a waiting state. The CPU 400 determines a task to be executed and causes the CPU 400 to execute the task. The task management means 403 also raises the priority of a task in the running state when it transitions to the waiting state, and lowers the priority of the task in the running state at predetermined intervals. ing.

In the task scheduling device configured as described above, the task management means 403 issues a request to abandon execution by the CPU 400 because the task is waiting for the completion of an operation of a peripheral device, etc., and when the task enters a waiting state, , raises the priority of this task and puts other tasks in an executable state into an executable state.

The task management means 403 also allows the task to be executed by the CPU 400.
Even if you do not issue a request to abandon execution by Then, decide which tasks should be placed in the running state.

By managing the execution of tasks based on priority in this way, tasks that frequently perform input/output processing and are often in a waiting state can be given a high priority and the operations of peripheral devices can be completed. This increases the possibility that the next process will be performed quickly, while tasks that do not perform input/output processing and occupy a large amount of the CPU'U 400 are given a lower priority and are placed on the CPU 400.
It is designed to perform efficient task scheduling by reducing the amount of occupancy of the task and not interfering with the execution of other tasks.

In recent years, many computer systems have been used to improve the human-machine interface by performing interactive processing with graph ink displays. In this type of computer system, in order to improve operability, it is necessary to maintain high responsiveness to operator operations.

However, when the conventional task scheduling device is applied to such a computer system, tasks that frequently perform drawing processing, etc. tend to occupy a large amount of the CPU, so their priority level decreases, and tasks that frequently perform drawing processing, etc. This has the problem that the process is frequently interrupted and responsiveness to operator operations tends to deteriorate. This problem becomes even more noticeable in computer systems in which the CPU directly performs operations such as drawing on a display.

In view of this, the present invention does not perform input/output processing that requires waiting for event completion for tasks that frequently perform man-machine ink face processing, such as outputting visible information such as drawing on a display. In addition, even if the task occupies a large amount of the CPU, by preventing the priority from decreasing, drawing processing etc. are prevented from being frequently interrupted, and responsiveness to operator operations is not impaired. The object of the present invention is to provide a task scheduling device that can perform efficient task scheduling.

In order to achieve the above object of reducing i to n.'', the present invention provides a task scheduling device that causes a CPU to selectively execute a plurality of tasks, and includes a priority storage means for storing the priority of each task. and each task is either in the running state where it is being executed by the CPU, in the runnable state where execution has been forcibly interrupted and is waiting to be put into the running state again, or in the runnable state. a state transition information storage means for storing state transition information indicating whether the state is in a waiting state waiting for a condition for the task to become satisfied; A man-machine ink face processing history storage means for storing the history, and each time a task in the running state transitions to the waiting state, the processing history is stored based on the priority of each task and the state transition information. In addition to determining whether a task is in a running state or a ready state, when a task in a running state transitions to a waiting state, the priority of the task is increased. The present invention is characterized by comprising task management means for lowering the priority of a task only when the degree of man-machine ink face processing in the task is small.

Production - J side - According to the above configuration, the man-machine ink face processing history storage means stores a history of whether each task has performed man-machine ink face processing, such as outputting visible information such as drawing on a display. remember. The task management means increases the priority of the task when the task in the running state transitions to the waiting state, and at predetermined intervals, increases the priority of the task.
Only when the degree of man-machine ink face processing in a running task is small, the priority of that task is lowered. Further, the task management means determines whether to put each task in an execution state or an executable state according to the priority set as described above.

Figure 1 is a block diagram showing the configuration of a task scheduling device in an embodiment of the present invention, Figure 2 is an explanatory diagram showing the state transition of tasks, and Figure 3 is a diagram showing the priority and priority of tasks. It is a time chart showing changes in state.

In FIG. 1, 101 is a priority storage means for storing the priority of each task, 102 is a state transition information storage means for storing state transition information indicating the state transition of each task, and 103 is a priority storage means for storing the priority of each task. A man-machine ink face processing history recording means 104 stores a history regarding whether or not man-machine interface processing has been executed, and 104 indicates the priority of each task at predetermined time intervals and each time a task in a running state transitions to a waiting state. , and state transition information, the task management means determines whether each task is placed in an execution state or an executable state, and also determines the priority of each task.

Further, 105 is a CPU that executes task A or task B based on the determination of the task status by the task management means 104, 106 is a peripheral device, and 107 is a display. This drawing process on the display 107 is performed by the CPU.
IO5 is designed to do this directly.

The state transition information stored in the state transition information storage means 102 indicates the state transition of each task, such as whether the task is in a running state, an executable state, or a waiting state. .

The execution state is a state in which the task is being executed on the CPUI 05, and the executable state is a state in which execution is forcibly interrupted by the periodic operation of the task management means 104 and waits for it to be executed again. The wait state is a state in which the CPU 105 issues a request to abandon execution in order to wait for the completion of an event, such as waiting for the peripheral device 106 to complete an operation in response to an input/output request made in the execution state. It is in a state where it is waiting for the execution state to be canceled and the conditions for becoming executable to be satisfied.

The man-machine ink face processing history storage means 103 includes:
The time during which each task is performing drawing processing on the display 107 is stored.

The task management unit 104 selects a running state from among tasks in a running state or an executable state, based on the task priority and state transition information, at predetermined time intervals and each time a task in a running state becomes a waiting state. a task determining means 111 which determines a task to be executed and causes the CPU 105 to execute this task; a priority increasing means 112 which increases the priority of a task when a task in an execution state transitions to a waiting state; A man-machine interface processing history determining means 113 that determines the degree of man-machine interface processing in a task in an execution state for each time;
Priority lowering means 114 is provided for lowering the priority of the task in the execution state only when the degree of man-machine ink face processing is small.

The task determining means 111 sets the task that has been in the executable state for a longer time to the execution state if tasks A and B are in the execution state or in the executable state and have the same priority. It has become. In addition, the priority increasing means 112 and the priority decreasing means 114 relatively raise and lower the priorities of tasks A and B, and
The upper limit of the difference in priority is set to 2 levels, and it is not possible to open more than 3 levels.

In the above configuration, the states of each task A and H can be changed as shown in FIG. 2 by the determination of the task management means 104.

That is, it is possible to transition to the execution state only from the executable state, it is possible to transition to the executable state from the execution state and the wait state, and it is possible to transition to the wait state only from the execution state.

Next, the task scheduling device schedules task A.
, H will be specifically explained based on the time chart shown in FIG. 3. In addition, the third
In the figure, thick lines indicate the execution state of the task, double lines indicate the execution state of the drawing process, solid cotton lines indicate the executable state, and dotted lines indicate the waiting state.

First, before time 1, task A is in the running state, task B
It is assumed that task A1B is in an executable state and has the same priority as task A1B.

When task A performs input/output processing at time 1, task A enters a wait state until the operation of peripheral device 106 is completed. Therefore, the priority raising means 112 raises the priority of task A to 2, and the task determining means 111 puts task B, which is in an executable state, into an execution state.

At time 2, the man-machine interface processing history determining means 113 determines that task B in the execution state has not performed drawing processing on the display 107 during the period from time 1 to time 2, and the priority lowering means 114 , in order to lower the priority of task B relative to task A, the priority of task A is raised. Furthermore, at time 2, since task A is still in the waiting state, the task determining means 111 causes task B to continue in the execution state.

During the period from time 2 to time 3, the operation of the peripheral device 106 due to the input/output processing of task A is completed, and task A becomes executable.

At time 3, the man-machine ink face processing history determining means 113 determines that task B in the execution state is
It is determined that no drawing processing is performed on the display 107 during the period up to this point. Therefore, the priority lowering means 114 attempts to raise the priority level of task B in order to relatively lower the priority level of task B, but since the difference in priority levels is already two levels, which is the upper limit, Leave the priority as is. Further, since the priority of task A is higher than the priority of task B, the task determining means 111 puts task A into an execution state and puts task B into an executable state.

At time 4, the man-machine ink face processing history determining means 113 determines that task A, which is in the execution state, has not performed drawing processing on the display 107 during the period from time 3 to time 4, and its priority is lowered. Means 114 lowers the priority of task A by a certain level. Task determining means 11
1 continues the execution state of task A because the priority of task A is still higher than the priority of task B.

At time 5, the man-machine interface processing history determining means 113 determines that task A frequently performs drawing processing on the display 107 during the period from time 4 to time 5. Therefore, the priority lowering means 114 is not activated and the priority of task A is not lowered. Therefore, task A
The priority of task B is still higher than the priority of task B, so
The task determining means 111 continues the execution state of task A.

At time 6, the man-machine ink face processing history determining means 113 determines that the frequency of drawing processing on the display 107 performed by task A during the period from time 5 to time 6 is low, and the priority lowering means 1.14 lowers the priority of task A. In this case, the priority of task A and the priority of task B are the same, but since task B has been in an executable state for a longer period of time, the task determining means 111 places task B in an executable state. and make task A executable.

As described above, in the task scheduling device of this embodiment, the man-machine ink face processing history storage means 103 records the time during which each task performs drawing processing when it performs drawing processing on the display 107. If the task does not issue a request to abandon the CPU 105 and the task determining means 111 determines whether to put each task into the execution state or into the executable state at predetermined intervals, the man-machine ink The face processing history determining means 113 determines, based on the drawing processing time stored in the man-machine interface processing history storage means 103,
It is determined whether the task in the execution state frequently performs drawing processing on the display 107, and if it is determined that the task is drawing, the priority lowering means 114 does not lower the priority of the task. Therefore, tasks that frequently perform drawing processing on the display 107 do not perform input/output processing, and their priority is not lowered even if they occupy a large amount of the CPU 105. Processing interruptions are suppressed.

In this embodiment, the priority level is increased and decreased relatively between the two tasks, but a method of absolute priority may be adopted. Also, unless the difference in priority between tasks exceeds a predetermined level, the priority is always raised or lowered, but it is not always necessary to raise or lower the priority, but there is a certain absolute priority. It is also possible to adopt a method that does not lower the temperature below the level of 100%. Furthermore, in this embodiment, the task management means 104 determines the task to be placed in the execution state based on the priority after raising and lowering the priority, but It is also possible to adopt a method of determining based on degree.

As described above, according to the present invention, the man-machine ink face processing history storage means stores the history regarding whether or not the man-machine interface processing of each task is executed; Only when the degree of man-machine interface processing in the task in the execution state is small;
By being equipped with a task management means that lowers the priority of the task, tasks that are performing man-machine ink face processing, such as outputting visible information such as drawing on a display, can be prevented from waiting for event completion. Even if there is no input/output processing and the CPU occupancy is large,
Since the priority does not drop, drawing processing etc. are not frequently interrupted.

Therefore, there is an effect that efficient task scheduling can be performed without impairing responsiveness to operator operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a task scheduling device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing task state transitions, and FIG. 3 is a time chart showing task priorities and state changes. , FIG. 4 is a block diagram showing the configuration of a conventional task scheduling device. 101... Priority storage means, 102... State transition information storage means, 103... Man-machine interface processing history storage means, 104... Task management means, 105
...CPU Agent Patent Attorney Shiro Neptune I Ku= Hehe

Claims (1)

[Claims] (1) A task scheduling device that causes a CPU to selectively execute a plurality of tasks, comprising a priority storage means for storing the priority of each task, and an execution state in which each task is being executed by the CPU. Either the execution is forcibly suspended and is in a runnable state waiting to be put into the running state again, or the wait state is waiting for a condition to become runnable. a state transition information storage means for storing state transition information indicating a state transition; a man-machine interface processing history storage means for storing a history regarding whether or not man-machine interface processing has been executed for each task; Each time a task in the running state transitions to the waiting state, it is determined whether to put each task in the running state or in the ready state based on the priority of each task and the state transition information. In addition, when a task in the running state transitions to the waiting state, the priority of the task is increased, and at predetermined intervals, only when the degree of man-machine interface processing in the task in the running state is small. A task scheduling device comprising: task management means for lowering the priority of a task;