JP2020091540A - Information processing device - Google Patents

Abstract

To provide an information processing device capable of preventing degrading of accuracy of execution result even when task priority is made higher.SOLUTION: An information processing device 1 includes a task execution unit 10, a queueing unit 121, a frequency determination unit 122, a priority changing unit 123, and a sequence order maintaining unit 124. The queueing unit 121 determines an execution schedule order of the task in the execution unit 10 on the basis of the priority of each task. The frequency determination unit 122 determines a frequency lowered task in which the execution frequency has lowered. The priority changing unit 123 makes higher the priority of the frequency lowered task. The sequence order maintaining unit 124 makes higher the priority of a related task whose execution result is referred to by the frequency lowered task so that the execution schedule order of the frequency lowered task is maintained.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an information processing device that manages an execution order of a plurality of tasks according to a priority.

Patent Document 1 discloses an information processing apparatus that controls the execution order of a plurality of tasks. In the information processing apparatus of Patent Document 1, the tasks waiting for execution are executed in the execution order according to the priority set for each task. The information processing apparatus raises the priority of a task whose processing omission frequency is equal to or higher than the processing omission allowable rate.

JP, 2013-88937, A

However, the controlled task may include a task that should be executed after the related task because it is executed based on the execution result of the related task. When the priority of these tasks is increased, the tasks may be executed before the related tasks as the execution order changes. Therefore, in the execution result of the task with the increased priority, the execution result of the related task is not reflected, and the accuracy may decrease.

An object of the present disclosure is to provide an information processing apparatus capable of suppressing a decrease in accuracy of execution results even when increasing the priority of tasks.

The above objective is achieved by a combination of the features recited in independent claims, and the subclaims define further advantageous embodiments of the present disclosure. The reference numerals in parentheses in the claims indicate the correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure. ..

An information processing apparatus according to an embodiment of the present disclosure for achieving the above-described object includes an execution unit (10) that sequentially executes tasks, and a scheduled execution order of a plurality of tasks waiting for execution by the execution units, with priorities set for each task. Based on the order determination unit (121), a frequency determination unit (122) for determining whether each task is a frequency-reduced task with a reduced execution frequency, and a priority for increasing the priority of the frequency-reduced task. When the frequency changing unit (123) and the frequency-reduced task are tasks that are executed based on the execution results of the related tasks associated with each other, the priority of the related task is maintained in the scheduled execution order for the frequency-reduced task. And an order maintaining unit (124).

According to the above configuration, the order maintaining unit increases the priority of the related task of the frequency-reduced task so as to maintain the scheduled execution order for the frequency-reduced task. As a result, the frequency-reduced task is executed before the related task even when the priority is increased by the priority changing unit. Therefore, even when the execution schedule order changes with the change in priority, the task can be executed by reflecting the execution result of the related task. Therefore, even when the priority of the task is increased, the accuracy reduction of the execution result is suppressed.

It is a figure which shows the structure of an information processing apparatus. It is a flowchart which shows the process in a task allocation management part. It is a figure which shows the example of a state change of a ready queue and a queue management part. It is a figure which shows the example of the allocation order of the task with respect to an execution part.

The information processing device 1 according to the embodiment of the present disclosure illustrated in FIG. 1 is an electronic control device used as an engine ECU that controls fuel injection and ignition timing of an engine in a vehicle, for example. The information processing device 1 is a microcomputer including a memory as a non-transitional and substantial storage medium in which software is recorded non-temporarily, a processor that executes software, an input/output interface, and the like. The memory stores a program of a real-time operating system (hereinafter, RTOS) and an application program that operates on the RTOS and provides a function as an engine ECU.

The information processing device 1 causes various processes for realizing the functions of the application program to operate as a plurality of tasks executed by the RTOS. A task is a set of execution units defined by RTOS. The information processing device 1 manages the execution state and execution order of each task, and sequentially executes each task. The tasks executed by the information processing device 1 include ignition control for each cylinder of the engine, acquisition of crank angle, acquisition of air-fuel ratio, acquisition of accelerator opening, calculation of fuel injection amount, opening control of throttle valve, etc. Separated processing is set individually. The information processing apparatus 1 manages the execution order of each task based on the priority set for each task. The information processing device 1 exhibits the functions of the execution unit 10, the interrupt controller 20, and the task allocation management unit 100 by executing the RTOS program on the processor.

The execution unit 10 is an area of the processor allocated to sequentially execute each task. The execution unit 10 includes an arithmetic circuit that performs arithmetic operations and logical operations related to each task, a register that temporarily stores data related to each task, and the like. When the task allocation condition is satisfied, the execution unit 10 requests the task allocation management unit 100 to allocate the task. The task allocation condition is, for example, a lapse of a predetermined time from the start of execution of the task being executed, the end of one-cycle calculation of the task being executed, or the like. When the execution unit 10 receives a new task allocation by the task allocation management unit 100, if there is a task that is being executed, the execution unit 10 saves the progress status and data of the operation related to that task, and executes the allocated task. To start. The execution unit 10 apparently parallelly and sequentially executes the tasks by switching the tasks being executed according to the assigned order.

The interrupt controller 20 is a module that outputs an interrupt request for each task based on whether the interrupt generation condition for each task is satisfied. For example, rising of an input signal to the information processing device 1, elapse of a predetermined time, completion of data transfer, and the like are individually set as interrupt conditions of each task. The interrupt controller 20 outputs an interrupt request for a task for which an interrupt condition is satisfied to the task allocation management unit 100.

The task allocation management unit 100 is, for example, an area of the processor allocated to manage tasks allocated to the execution unit 10. The task allocation management unit 100 receives an interrupt request for each task from the interrupt controller 20, and allocates each task as a task to be executed by the execution unit 10 according to the priority set for each task and the timing at which the interrupt request is received. The task assignment management unit 100 has functions as a state management unit 110 and a task control unit 120.

The status management unit 110 is a storage area for managing the execution status of each task. The state management unit 110 includes a ready queue 111, a queue management unit 112, and a related task table 113.

The ready queue 111 is an area for storing the interrupt request of each task. The interrupt request of each task is stored in the ready queue 111 according to the order in which the interrupt request is received, for each interrupt request having the same priority set in the task. One of the stored interrupt requests for each task is taken out each time a task allocation request is received from the execution unit 10. The task corresponding to the fetched interrupt request is assigned as the task to be executed next by the execution unit 10. Therefore, the array of each interrupt request in the ready queue 111 corresponds to the “execution scheduled order” indicating the schedule of the execution order at that time.

The task for which an interrupt request has been issued is taken out in order from the interrupt request of the task with the highest priority among the stored interrupt requests. In the present embodiment, the smaller the numerical value set as the priority, the higher the priority. When a plurality of interrupt requests having the highest priority are stored, the tasks of the interrupt request stored first are assigned in order. Therefore, the order of execution schedules may change until the interrupt request is actually allocated, for example, when an interrupt request having a higher priority than any of the stored interrupt requests is newly stored.

The queue management unit 112 is an area for storing data for managing storage of interrupt requests for the ready queue 111. The queue management unit 112 stores a queuing number, a preset priority, and a change threshold for each task managed by the task allocation management unit 100. The queuing number is the number of interrupt requests currently stored in the ready queue 111 for each task. The queuing number is the number of interrupt requests of each task waiting for execution, and corresponds to the "execution waiting number".

The priority is a parameter preset for each task in order to sort the interrupt requests in the ready queue 111. The priority is set to be higher for a task in which it is preferable that the time from the generation of an interrupt request to the allocation is shorter. Five levels from 0 to 4 are set as the priorities of the present embodiment. Up to two priorities, a normal priority and a temporary priority, can be set for each task. The normal priority is a priority referred to when storing in the ready queue 111. The temporary priority is a priority temporarily applied to an interrupt request of a task whose execution schedule order is changed when the execution schedule order of tasks stored in the ready queue 111 is changed. The temporary priority is set to a higher priority than the normal priority.

The change threshold is a parameter set in advance as a condition for changing the scheduled execution order by applying the temporary priority to the interrupt request of each task. The execution schedule order is changed when any of the tasks becomes a frequency-reduced task with a reduced execution frequency. However, the decrease in the execution frequency indicates a state where the execution frequency is below the allowable execution frequency range set for each task. The change threshold value of this embodiment is set as a threshold value of the queuing number of each task. The change threshold is set based on the expected frequency of interrupt requests and the lower limit of the allowable execution frequency. For example, it is set to a larger value as the occurrence frequency of interrupt requests is higher, and is set to a smaller value as the lower limit of execution frequency is higher.

In this embodiment, the queue management unit 112 stores data for queuing management for three tasks, task A, task B, and task C. Task A is a task of calculating the fuel injection amount based on the current crank angle. The task A has a normal priority of 4 and a temporary priority of 1. Further, in the task A, 3 is set as the change threshold.

Task B is a task for acquiring the crank angle. Task A is executed based on the latest crank angle acquired in task B. Therefore, the task B is set to have a normal priority of 3 which is one step higher than the normal priority of the task A so that it is executed immediately before the task A. Further, in the task B, 0 is set as the temporary priority and 4 is set as the change threshold. The difference between the temporary priority levels of task A and task B is set to match the difference between the normal priorities. That is, the temporary priority of task A is set to be one step higher than the temporary priority of task A to be 0. The interrupt request of the task B occurs more frequently than the interrupt request of the task A because of noise suppression and the like.

Task C is a task of performing ignition processing for each cylinder. The task C has a normal priority of 2. The task C has a higher normal priority than any other task, and thus the execution frequency does not decrease. Therefore, the task C is not set with the temporary priority and the change threshold. The temporary priorities of the tasks A and B are set higher than the normal priorities set for any of the tasks.

The related task table 113 is an area for storing a relationship between each task and a related task associated with the task in advance. A related task is a task whose priority is changed in conjunction when the execution schedule order is changed by applying a temporary priority to a certain task. The task set as the related task is, for example, a task in which another task is executed based on the execution result of the task. Specifically, when referring to the data obtained as the execution result of another task in executing a predetermined task, the task of the side that refers to the data is previously set as a related task to the task of the side that refers to the data. It is set.

For example, in the present embodiment, the task A for calculating the fuel injection amount is set as the related task to the task B for acquiring the crank angle to be referred to in the calculation. Task A calculates the fuel injection amount based on the latest crank angle by task B, which is a related task. The tasks set as the related tasks in the present embodiment include tasks other than the above-mentioned relationships. For example, in this embodiment, task A is set as a related task with respect to task B. That is, the task that refers to the data is also set as a related task to the task that refers to the data. The related task table 113 stores the relationship between each task and related tasks in a table format separately from the queue management unit 112.

The task control unit 120 is a control circuit that controls the acceptance of an interrupt request and the assignment of a task to the execution unit 10 based on each data stored in the state management unit 110. The task control unit 120 functions as a queuing unit 121, a frequency determination unit 122, a priority changing unit 123, and an order maintaining unit 124.

When receiving the interrupt request output from the interrupt controller 20, the queuing unit 121 stores the received interrupt request in the ready queue 111. The queuing unit 121 reads the normal priority of the task that received the interrupt request from the queue management unit 112. The queuing unit 121 stores the interrupt request at the end of the range corresponding to the normal priority in the ready queue 111. That is, the queuing unit 121 corresponds to an “order determining unit” that determines the scheduled execution order based on the normal priority among the priorities set for each task. The queuing unit 121 updates the queuing number stored in the queue management unit 112 to the value at the time of storage completion for the task storing the interrupt request. The queuing unit 121 also updates the queuing number when the interrupt request is taken out from the ready queue 111 and assigned to the execution unit 10.

The frequency determination unit 122 determines whether or not each task is a frequency-reduced task whose execution frequency has been reduced. The frequency determination unit 122 of the present embodiment determines that each task is a frequency-reduced task based on the queuing number stored in the queue management unit 112 and the change threshold. For example, when the queuing unit 121 stores an interrupt request and updates the queuing number for any task, the frequency determining unit 122 reads the queuing number after the task update and the change threshold. When the queuing number is equal to or larger than the change threshold, the frequency determination unit 122 determines that the task storing the interrupt request is the frequency-reduced task.

The priority changing unit 123 increases the priority of the task determined by the frequency determining unit 122 to be a frequency-reduced task. The priority changing unit 123 changes the priority of the frequency-reduced task stored in the ready queue 111 to a temporary priority higher than the normal priority. The priority changing unit 123 reduces the queuing number of the frequency-reduced task when changing the priority. For example, the priority changing unit 123 reduces the queuing number to 1. Specifically, the priority changing unit 123 deletes all the interrupt requests of the frequency-reduced task stored according to the normal priority from the ready queue 111, and rewrites only one interrupt request according to the temporary priority to the ready queue 111. Store. When storing the interrupt request according to the temporary priority, the priority changing unit 123 updates the queuing number to be 1.

The order maintaining unit 124 raises the priority of the related task associated with the frequency-reduced task so as to maintain the scheduled execution order for the frequency-reduced task. That is, the priority is changed so that the context of the order of execution schedule before increasing the priority of the frequency-reduced task is maintained even after increasing the priority of the frequency-reduced task. When the frequency determining unit 122 determines that any of the tasks is a frequency-reduced task, the order maintaining unit 124 reads the related task of the task from the related task table 113. The order maintaining unit 124 also reads the temporary priority from the queue managing unit 112 for the related task read from the related task table 113. The order maintaining unit 124 changes the priority of the related task to a temporary priority that is higher than the normal priority.

The difference between the temporary priorities set for the task A and the task B is set so as to match the difference between the normal priority stages. Therefore, when one of the task A and the task B becomes a frequency-reduced task, the priority of the other related task is changed so that the relative scheduled execution order of the related task with respect to the frequency-reduced task is maintained. .. Further, the temporary priorities of the tasks A and B are set higher than the normal priorities of any of the tasks, and the difference between the priorities is set to one step. As a result, when one of the task A and the task B becomes a frequency-reduced task, the priority of the other related task is changed so as to be executed continuously with the frequency-reduced task. The order maintaining unit 124 reduces the queuing number of related tasks when changing the priority of the related tasks. For example, the order maintaining unit 124 reduces the queuing number of related tasks to 1.

[Operation of task control unit 120]
An operation example of the task control unit 120 will be described. When the task control unit 120 receives an interrupt request from the interrupt controller 20, the task control unit 120 sequentially executes the processes shown in the flowchart of FIG. 2 from S1.

In S1, the normal priority is acquired for the task that received the interrupt request, and the interrupt request of the task is stored in the ready queue 111 according to the acquired normal priority. In S2, the queuing number of the task storing the interrupt request in S1 is updated.

In S3, it is determined whether or not the task whose queuing number has been updated in S2 is a reduced frequency task. That is, it is determined whether or not the queuing number of the updated task is equal to or larger than the change threshold. If it is equal to or greater than the change threshold, the process proceeds to S4 as a frequency lowering task, and if it is less than the change threshold, the process shown in FIG.

In S4, it is determined whether or not a related task is set in the related task table 113 for the task that is determined to be the frequency-reduced task in S3. If the related task is set, the process proceeds to S5, and if it is not set, the process proceeds to S7.

In S5, the interrupt requests of the related tasks queued according to the normal priority are reduced, and only one interrupt request is left in the ready queue 111.

In S6, the temporary priority of the task set as the related task is acquired, and the priority of the interrupt request related to the related task remaining in the ready queue 111 is changed from the normal priority to the temporary priority. The position of the interrupt request related to the related task is moved according to the change of the priority, and the scheduled execution order is updated.

In S7, the interrupt requests of the frequency-reduced tasks queued according to the normal priority are reduced, and only one interrupt request is left in the ready queue 111.

In S8, the temporary priority of the frequency-reduced task is acquired, and the priority of the interrupt request related to the frequency-reduced task remaining in the ready queue 111 is changed from the normal priority to the temporary priority. The position of the interrupt request relating to the frequency-reduced task is moved according to the change of the priority, and the scheduled execution order is updated.

An example of the state change of the ready queue 111 and the queue management unit 112 due to the operation of the task control unit 120 illustrated in FIG. 2 will be described. FIG. 3 shows the behavior when the interrupt request of the task A is further stored in the ready queue 111 in which the queuing number of the task A is 2. By S1 and S2 shown in FIG. 2, the interrupt request of task A is further stored at the end of the range of priority 4 in the ready queue 111, and the queuing number of task A stored in the queue management unit 112 is Updated from 2 to 3. As a result, task A is determined to be a frequency-reduced task in S3, and task B is determined to be a related task of the frequency-reduced task in S4.

Through S5 and S6, among the interrupt requests of task B stored in the range of priority 3 in the ready queue 111, only one is moved to the range of priority 0 and the rest are deleted. Further, the queuing number of task B is updated to 1. Through S7 and S8, only one of the interrupt requests of task A stored in the range of priority 4 in the ready queue 111 is moved to the range of priority 1, and the rest are deleted. Further, the queuing number of task A is updated to 1.

An example of the change over time of the task executed by the execution unit 10 due to the operation of the task control unit 120 will be described with reference to FIG. FIG. 4 shows switching of tasks executed by the execution unit 10 when the interrupt request frequency of the task C having a high priority is increased due to, for example, high-speed running of the vehicle. Due to the increase in the interrupt requests of the task C having the high normal priority, the task A having the lowest normal priority is in the state of not being executed although the interrupt request is received.

It is assumed that the queuing number of the task A becomes 3 at the time t1 in response to the interrupt request of the task A. As a result, it is determined that task A is a frequency-reduced task and task B is a related task to the frequency-reduced task. The positions of task A and task B in the ready queue 111 are changed according to the temporary priority. At time t2, the task is allocated to the execution unit 10, and the task B having the temporary priority of 0 is allocated. Although the interrupt request of the task C is generated at the time t3, the normal priority of the task C is the priority 2 which is lower than the priority 1 which is the temporary priority of the task A. Therefore, when the task allocation to the execution unit 10 occurs again at the time t4, the task A is allocated immediately after the task B and is prioritized over the task C.

[Summary of Embodiments]
As described above, according to the embodiment described above, the order maintaining unit 124 increases the priority of the related task of the frequency-reduced task so as to maintain the scheduled execution order for the frequency-reduced task. As a result, the frequency-reduced task is executed without being executed before the related task even when the priority is changed by the priority changing unit 123. Therefore, even when the execution schedule order changes with the change in priority, the task can be executed by reflecting the execution result of the related task. Therefore, even when the priority of the frequency-reduced task is increased, the reduction in the accuracy of the execution result is suppressed.

In addition, in the present embodiment, the frequency determination unit 122 determines a task whose queuing number is equal to or greater than the change threshold as a frequency-reduced task. According to such a determination, it is possible to determine the decrease in the execution frequency without newly providing a timer or a missing rate calculating unit for each task. Therefore, it is possible to suppress the cost for determining the execution frequency.

Further, in the present embodiment, the priority changing unit 123 reduces the number of execution waits of the frequency-reduced task when the priority of the frequency-reduced task is increased. Due to the decrease in the number of waiting executions, the time until the number of waiting executions of the frequency-reduced task becomes equal to or higher than the change threshold again. Therefore, it is possible to prevent the priority changing unit 123 from changing the priority due to the determination that the task is a frequency-reduced task. Therefore, it is possible to suppress a decrease in the execution frequency of a task having a higher priority than the frequency-reduced task.

Further, in this embodiment, the priority changing unit 123 changes the priority of the frequency-reduced task to a higher priority than the normal priority set for each task. Therefore, after the frequency determination unit 122 determines that a frequency-reduced task has occurred, the frequency determination task 122 assigns the task to the execution unit 10 without waiting for assignment of tasks other than the related tasks. As a result, the frequency-reduced task is shortened in the period from the determination of the frequency-reduced task to the execution.

Further, in the present embodiment, the order maintaining unit 124 increases the priority of the related task so that the scheduled execution order of the frequency-reduced task is immediately after the related task. Therefore, the frequency-reduced task is assigned to the execution unit 10 from the assignment of the related task without waiting for the assignment of another task. As a result, the frequency-reduced task can be executed based on the execution result of the newer related task. Therefore, the accuracy of the execution result of the frequency-reduced task can be further improved.

<Other Embodiments>
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and the following modifications are also included in the technical scope of the present disclosure. Various modifications can be made without departing from the scope. In the following description, elements having the same reference numerals as those used up to now are the same as the elements having the same reference numerals in the previous embodiments, unless otherwise specified. Further, when only a part of the configuration is described, the above-described embodiments can be applied to other parts of the configuration.

In the above-described embodiment, the frequency determination unit 122 determines whether or not the frequency reduction task is based on the queuing number. However, the configuration may be such that the processing omission rate or waiting time of each task is used for the determination. Further, in this case, it is not necessary to reduce the queuing number when changing the priority.

In the above-described embodiment, the temporary priority of the frequency-reduced task and the related task is set higher than the normal priority of any task and set to different priorities. However, the temporary priority to be set is not limited to this as long as the execution schedule order of the related task of the frequency-reduced task can be maintained. For example, the same temporary priority may be set, and the priorities of the movement destinations may be stored in the order according to the original execution schedule order based on the difference in the normal priorities. Further, in this case, the temporary priority may match the normal priority of any task.

In the above-described embodiment, three tasks are set as tasks managed by the task assignment management unit 100, and only one task is set as a related task for a certain task. However, the number of tasks may be three or more, and in that case, a plurality of tasks may be set as related tasks for a certain task. For example, as the tasks managed by the task allocation management unit 100, a task for acquiring the air-fuel ratio, a task for acquiring the accelerator opening, a task for calculating the throttle opening, and the like may be further set.

As a related task to the task of calculating the fuel injection amount, a task of acquiring the air-fuel ratio may be set in addition to the task of acquiring the crank angle. When a plurality of related tasks are set, the order maintaining unit 124 may change the priority of each related task so as to maintain the relationship between the execution schedule orders of the related tasks. With such a configuration, even in a configuration in which a plurality of related tasks are set for one task, it is possible to maintain the execution order assumed at the time of designing and increase the priority. Further, the related task may include a frequency-reduced task and a task whose execution schedule order is not continuous.

In the above-described embodiment, for a predetermined task, a task that refers to the execution result of the task is also set as the related task. However, such a task does not have to be set as a related task.

In the above-described embodiment, the order maintaining unit 124 always changes the priority of the related task when the related task is set as the frequency-reduced task. However, it may be possible to change only the priority of the frequency-reduced task without changing the priority of the related task. For example, when the queuing number of related tasks is sufficiently small, it is highly possible that the related tasks are periodically executed with a sufficient execution frequency. Therefore, it can be considered that the frequency-reduced task can be executed by referring to the execution result of the related task without changing the priority of the related task. Therefore, when the queuing number of the related tasks is less than the predetermined maintenance threshold, the order maintaining unit 124 maintains the priority of the related tasks at the normal priority and changes the priority of only the frequency-reduced tasks. You can also do it. With such a configuration, it is possible to suppress a decrease in the execution frequency of the task having a higher priority than the related task and maintain the execution frequency of the frequency-reduced task.

In the above-described embodiment, the information processing device 1 is an electronic control device used as an engine ECU. However, the application of the information processing device 1 is not limited to this, and the application software stored in the memory can be appropriately changed and used for other purposes.

In the above-described embodiment, the task allocation management unit 100 allocates the execution unit 10 when a predetermined time elapses or the cycle ends. However, as long as the allocation method is based on the priority, the determination timing of allocation is not limited to this, and can be changed appropriately. As an example, a method of determining whether or not a task having a higher priority than the task being executed is stored in the ready queue 111 every predetermined period, and switching to the task if the high priority task is stored Can be adopted. When such switching is performed, the task being executed saves the progress status of the processing of a series of cycles and stores an interrupt request at the head of the ready queue 111.

1 Information Processing Device, 10 Execution Unit, 121 Queuing Unit (Order Determining Unit), 122 Frequency Judgment Unit, 123 Priority Change Unit, 124 Order Maintenance Unit

Claims (6)

An execution unit (10) for sequentially executing tasks,
An order determination unit (121) that determines the scheduled execution order of the plurality of tasks waiting for execution by the execution unit, based on the priority set for each task;
A frequency determination unit (122) that determines whether or not each of the tasks is a frequency-reduced task with a reduced execution frequency;
A priority change unit (123) for increasing the priority of the frequency-reduced task,
An order in which, when the frequency-reduced task is the task that is executed based on the execution result of the associated related task, the priority of the related task is increased to maintain the scheduled execution order for the frequency-reduced task. An information processing apparatus comprising: a maintenance unit (124). The information processing apparatus according to claim 1, wherein the frequency determination unit determines that the task, the number of waiting for execution of which is equal to or greater than a change threshold, is the frequency-reduced task. The information processing apparatus according to claim 2, wherein when the priority of the frequency-reduced task is increased, the priority changing unit reduces the number of execution waits of the frequency-reduced task. The information according to any one of claims 1 to 3, wherein the priority changing unit changes the priority of the frequency-reduced task to a higher priority than any of the priorities set for the respective tasks. Processing equipment. The information processing apparatus according to claim 1, wherein the order maintaining unit increases the priority of the related task so that the related task and the frequency-reduced task are continuously executed. The said order maintenance part raises a priority so that the execution schedule order between each said related task may be maintained, when several said related tasks are linked|related with the said frequency fall task. The information processing apparatus according to any one of items.

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