KR20100060312A - Method for scheduling task in embedded operating system of automobile - Google Patents

Abstract

PURPOSE: A task scheduling method of car embedded OS(Operating System) is provided to guarantee task processing on real time by processing a task with a fast deadline firstly. CONSTITUTION: A task with a deadline is divided and stored according to a priority in a plurality of standby queues with a queue priority(S130). A storage location of the tasks is changed within each standby queue based on the deadline of the tasks saved in the standby queue(S140). The task saved in the standby queue is detected according to stored order(S150). The task with the earliest deadline is changed to the storage location which is most quickly processed.

Description

Method for scheduling task in embedded operating system of automobile}

The present invention relates to a task scheduling method of an embedded operating system used in a vehicle, and more particularly, to a task scheduling method of an automotive embedded operating system for improving the real-time scheduling algorithm of the automotive embedded operating system.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunication Research and Development. [Task name: Development of embedded SW platform technology for future intelligent automotive electronics].

Recently, as IT technology is applied to electric and electronic fields among automotive related technology fields, the proportion of electronic devices in automobiles is increasing. BACKGROUND Electronic devices mounted in automobiles are applied to vehicle driving devices for comfortable driving. Accordingly, a real-time operating system, which is software for controlling the electronic device mounted on the vehicle, is installed.

Real-time operating systems use many definitions, but the following definitions are most commonly used. That is, a real-time operating system is an operating system that guarantees to handle interrupts within a given specific time, and is an operating system suitable for controlling application programs or hardware affected by timeouts such as embedded systems. Often, the real-time operating system is abbreviated as RTOS (Real-Time Operating System). In other words, RTOS can be seen as an operating system with a hardware-related time constraint added to a general operating system.

Real-time operating systems (RTOS) are rapidly spreading into the automotive industry to address the complexity of developments due to the exponential growth in automotive software size due to the increase in electronics. The representative of automotive RTOS is OSEK operating system. OSEK OS is an automotive real-time operating system developed by European automakers such as BMW, Volkswagen, Siemens and Renault.

The OSEK operating system, a standard for real-time operating systems designed for automobiles, provides tasks such as task creation, event-based task scheduling, and task synchronization. Here, the scheduling algorithm of the OSEK operating system has 16 priorities. Sixteen priority wait queues are processed using the First In First Out (FIFO) algorithm.

As shown in FIG. 1, in the OSEK operating system's waiting algorithm method, there are 16 waiting queues 100, and each queue has a task 300 having a corresponding priority. The scheduler 200 selects a task 300 to perform while sequentially checking these queues. That is, the wait algorithm method of the OSEK operating system processes the task 300 that entered first even if the urgent task 300 enters the wait queue 100. Thus, the conventional OSEK operating system for automobiles has a problem in that it cannot process in an early time for the urgent task 300 and starts processing after the processing of the previously entered tasks 300 ends, thereby failing to guarantee real time.

The scheduling algorithm of the OSEK operating system has a fixed priority. That is, when the task 300 enters the scheduler 200, the task 300 enters the waiting queue 100 according to the priority given to the task 300. At this time, the task 300 has already been prioritized when entering the 16 waiting queues 100, and the task 300 that arrived first in the waiting queue 100 is designed to operate in the central processing unit 400 first. . Here, since the priority given to the task 300 is a priority set by the programmer, the priority is not changed until the programmer corrects it. Then, the scheduling algorithm of the conventional OSEK operating system fails to process the task 300 which has to be urgently processed in time, resulting in a fatal error in the system.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-described conventional problems, and an object thereof is to provide a task scheduling method of an embedded operating system for a vehicle in which task processing is scheduled based on a deadline of a task for controlling an electronic device of a vehicle. have.

In order to achieve the above object, a task scheduling method of an automotive embedded operating system according to the present invention is a task scheduling method of an automotive embedded operating system installed to control an electronic device of a vehicle. Distributing and storing the plurality of waiting queues having the queue priority according to the priority; (b) changing a storage location of tasks in each wait queue based on a deadline of tasks stored in each wait queue; And (c) detecting the tasks stored in the waiting queue in the order of storage.

In step (b), the task with the earliest deadline is changed to the storage location that is processed fastest.

In step (c), the task is detected from the waiting queue having the highest queue priority.

Alternatively, a task scheduling method of an automotive embedded operating system installed to control an electronic device of a vehicle, the method comprising: (a) distributing and storing a task having a deadline according to priority among a plurality of waiting queues having a queue priority; Making; (b) comparing the deadlines of one or more tasks stored in the waiting queue to specify a unique processing order number for each task; And (c) detecting a task stored in the waiting queue based on the processing sequence number.

In step (b), the earliest processing time is assigned to the task having the earliest deadline.

In step (c), the task having the earliest processing sequence is detected.

In step (c), the task is detected from the waiting queue having the highest queue priority.

(b-1) further comprising changing a storage location of the tasks in each waiting queue based on the processing order of the tasks stored in the respective waiting queue, and in step (b-1), having the fastest processing sequence. Change the task to the storage location that is processed fastest.

In step (a), the task is stored in a waiting queue having a queue priority corresponding to the priority of the task.

In step (a), the task is distributed and stored in four waiting queues.

According to the present invention, the task scheduling method of the embedded operating system for automobiles may first process a task having an early deadline, thereby ensuring real-time task processing.

In addition, the task scheduling method of the automotive embedded operating system may change the priority of the task based on the deadline of the task, thereby preventing a fatal error of the system caused by failing to process the task in time.

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. . First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a view for explaining the configuration of the task scheduling apparatus of the embedded operating system for a vehicle according to an embodiment of the present invention.

As shown in FIG. 2, the task scheduling apparatus of the automotive embedded operating system includes four wait queues 100 and a scheduler 200.

In the waiting queue 100, a unique queue priority is set for each waiting queue 100. That is, '0' as the queue priority for the first queue 100a, '1' as the queue priority for the second queue 100b, '2' as the queue priority for the third queue 100c, '3' is respectively set as the queue priority in the fourth standby queue 100d. Here, the queue priority set in the waiting queue 100 is a priority for the processing of the task 300 stored in each waiting queue 100, and a task stored in the waiting queue 100 having a high queue priority. 300 is processed first.

The waiting queue 100 stores a task 300 corresponding to the set queue priority. That is, the standby queue 100 compares the priority included in the task 300 input through the scheduler 200 with the queue priority set in each of the standby queues 100, and thus queue priority of the standby queue 100. The task 300 having the priority corresponding to (or the same) is stored. At this time, the task 300 stored in the waiting queue 100 includes a deadline of the task 300 with priority. The deadline of the task 300 is information for processing the corresponding task 300 within a time when the deadline does not exceed, based on the processing time that each task 300 is to be processed.

The scheduler 200 distributes and stores the task 300 having a deadline to the plurality of waiting queues 100. In other words, when a task 300 having a deadline comes in from the module, the scheduler 200 assigns a priority to the task 300 and stores it in the waiting queue 100 corresponding to the priority. Here, the task 300 is given priority and is set by the user (or programmer). Since the priority of task 300 uses a fixed priority algorithm, the priority given to task 300 is not changed until the user (or programmer) modifies the priority.

The scheduler 200 changes the storage location of the tasks 300 based on the deadlines of the tasks 300 stored in the respective waiting queues 100. That is, the scheduler 200 sequentially stores the storage locations of the tasks 300 based on the deadlines of the tasks 300 from the queue 100 having the highest priority to the queue 100 having the lowest priority. Change Here, the scheduler 200 changes to a storage location that is processed fastest in the task 300 having the earliest deadline. As such, the task scheduling method of the automotive embedded operating system changes a priority of the task 300 based on the deadline of the task 300, thereby preventing a fatal error of the system caused by failing to process the task 300 in time. You can prevent it.

The scheduler 200 detects the task 300 stored in the waiting queue 100 and transmits the detected task 300 to the CPU 400. That is, the scheduler 200 detects and stores the stored task 300 in the order in which the storage location of the task 300 is changed, and transmits the stored task 300 to the CPU 400. Here, the scheduler 200 preferentially detects the tasks 300 stored in the waiting queue 100 having the highest queue priority.

The scheduler 200 may detect the task 300 having the earliest deadline among the tasks 300 stored in the waiting queue 100 and transmit the detected task 300 to the CPU 400. That is, the scheduler 200 detects the task 300, which has the earliest deadline, among the tasks 300 stored in the waiting queue 100, in order to process the task 300 that has an imminent deadline. To send). Here, the scheduler 200 preferentially detects the tasks 300 stored in the waiting queue 100 having the highest queue priority. As such, the task scheduling method of the automotive embedded operating system may process the task 300 having an early deadline first, thereby ensuring real-time processing of the task 300.

The scheduler 200 may assign the earliest processing time to the task 300 having the earliest deadline, detect the task 300 having the earliest processing time, and transmit the same to the CPU 400. That is, the scheduler 200 compares the deadlines of the tasks 300 stored in the respective waiting queues 100 and assigns the processing sequence numbers in the order of the early deadlines, and detects the task 300 having the fastest processing sequence. do. Here, the scheduler 200 preferentially detects the tasks 300 stored in the waiting queue 100 having the highest queue priority.

3 is a flowchart illustrating a task scheduling method of an automotive embedded operating system according to a first exemplary embodiment of the present invention, and FIGS. 4 to 6 illustrate a task scheduling method of an automotive embedded operating system according to the first exemplary embodiment. It is for the drawing.

First, when a driver generates a control signal for controlling an electronic device mounted on a vehicle, a task 300 generated by a request of a module for controlling the electronic device is transmitted to the scheduler 200 of the embedded operating system.

Upon receiving the task 300 (S100; YES), the scheduler 200 detects a priority included in the task 300 (S110). In this case, the task 300 may include any one of four waiting queues 100 (for example, the first waiting queue 100a, the second waiting queue 100b, the third waiting queue 100c, and the fourth waiting queue 100d). It includes a priority corresponding to one and the deadline of the task (300). For example, as shown in FIG. 4, when the four waiting queues 100 each have a queue priority of '0' to '3', the task 300 is one of '0' to '3'. Includes the priority of. The scheduler 200 detects a priority included in the received task 300.

Next, the scheduler 200 sets the waiting queue 100 to store the task 300 based on the detected priority of the task 300 and the queue priority of each waiting queue 100 (S120). That is, the scheduler 200 sets the waiting queue 100 having the same queue priority as the priority of the detected task 300 as the waiting queue 100 to store the corresponding task 300. For example, the scheduler 200 may have a waiting queue 100 having a '0' as the queue priority when the priority detected from the task 300 is '0' (for example, the first waiting queue of FIG. 4). (100a)) to the waiting queue 100 to store the task 300.

Next, the scheduler 200 stores the received task 300 in the waiting queue 100 set in step S120 (S130). The waiting queue 100 stores the task 300 from the scheduler 200 to be located in the next order of the stored tasks 300. For example, as shown in FIG. 5, three tasks 300 (for example, task 1 (300a), task 2 (300b), and task 3 (300c)) are stored in the first queue 100a. In this case, the first wait queue 100a stores the task 300 (eg, task 4 (300d)) from the scheduler 200 in a storage location corresponding to the fourth process. Here, block '3' of the waiting queue 100 is a storage position corresponding to the highest priority processing, and block '0' is a storage position corresponding to the final processing.

When the storing of the task 300 is completed, the scheduler 200 stores the positions of the tasks 300 based on the deadlines of the tasks 300 stored in the waiting queue 100 storing the task 300 from the module. To change (S140). That is, the scheduler 200 changes the storage location of the task 300 in the order of the deadlines included in each task 300. Here, the scheduler 200 stores the task 300 having the earliest deadline in the storage location corresponding to the highest priority processing, and stores the task 300 having the latest deadline in the storage location corresponding to the final processing. . For example, as shown in FIG. 6A, there are four tasks 300 that include each deadline. As shown in (b) of FIG. 6 in the block of the first waiting queue 100a, task 300 (for example, task 1 (300a), task 2 (300b), task 3 (300c), task 4 (300d)). )) Are stored respectively. Here, block '3' of the waiting queue 100 is a storage position corresponding to the highest priority processing, and block '0' is a storage position corresponding to the final processing. In this case, the scheduler 200 removes task 1 (300a) with the earliest deadline in block 3 of the first queue (100a) and task 3 (300c) with the second deadline. Task 4 (300d) having the third early deadline in block '2' of the first queue (100a), Task 2 having the latest deadline in the block '1' of the first queue (100a) 300b is stored in the block '0' of the first waiting queue 100a. Accordingly, the storage location of the tasks 300 stored in the first waiting queue 100a is as shown in FIG. As such, the task scheduling method of the automotive embedded operating system changes a priority of the task 300 based on the deadline of the task 300, thereby preventing a fatal error of the system caused by failing to process the task 300 in time. You can prevent it.

When the change of the storage location of the task 300 is completed, the scheduler 200 sequentially detects the task 300 stored in the waiting queue 100 and transmits it to the CPU 400 (S150). That is, the scheduler 200 sequentially detects the task 300 stored in the storage location corresponding to the highest priority processing position and transmits the same to the central processing unit 400. For example, as shown in (c) of FIG. 6, when four tasks 300 are stored in the waiting queue 100, the scheduler 200 blocks '3' according to processing priority. In addition, tasks 300 stored in blocks '2', '1', and '0' are sequentially detected and transmitted to the CPU 400. Here, the scheduler 200 detects the task 300 at the next location after the processing time of the task 300 detected first between the task 300 and the task 300 elapses.

Thereafter, when the new task 300 is transmitted, the scheduler 200 performs the above-described steps S100 to S150 to schedule the processing sequence of the task 300. As described above, according to the first embodiment, by changing the storage location according to the deadline of the task after the task is stored in the waiting queue, the processing speed can be improved when the task is detected according to the deadline of the task.

7 is a flowchart illustrating a task scheduling method of an automotive embedded operating system according to a second exemplary embodiment of the present invention, and FIG. 8 is a flowchart illustrating a task scheduling method of an automotive embedded operating system according to a second exemplary embodiment of the present invention. It is for the drawing.

 First, when a driver generates a control signal for controlling an electronic device mounted on a vehicle, a task 300 generated by a request of a module for controlling the electronic device is transmitted to the scheduler 200 of the embedded operating system. .

Upon receiving the task 300 (S200; YES), the scheduler 200 detects a priority included in the task 300 (S210). In this case, the task 300 includes a priority corresponding to any one of the four waiting queues 100 and a deadline of the task 300.

Next, the scheduler 200 sets the waiting queue 100 to store the task 300 based on the detected priority of the task 300 and the queue priority of each waiting queue 100 (S220). That is, the scheduler 200 sets the waiting queue 100 having the same queue priority as the priority of the detected task 300 as the waiting queue 100 to store the corresponding task 300. For example, when the priority detected by the task 300 is '0', the scheduler 200 stores a waiting queue 100 having a '0' as the queue priority to store the task 300. 100).

Next, the scheduler 200 stores the received task 300 in the set waiting queue 100 (S230). The waiting queue 100 stores the task 300 from the scheduler 200 to be located in the next order of the stored tasks 300. For example, when three tasks 300 are stored, the waiting queue 100 stores the task 300 from the scheduler 200 in a storage location corresponding to the fourth process.

When the storing of the task 300 is completed, the scheduler 200 determines the processing order of the tasks 300 based on the deadlines of the tasks 300 stored in the waiting queue 100 storing the task 300 from the module. Set (S240). That is, the scheduler 200 sets the processing order of the task 300 in the order of the deadlines included in each task 300. Here, the scheduler 200 sets the highest priority order in the task 300 having the earliest deadline, and sets the final priority order in the task 300 having the latest deadline. For example, as shown in FIG. 8A, four tasks 300 are stored in the first waiting queue 100a. The four tasks 300 include their respective deadlines, as shown in FIG. In this case, the scheduler 200 sets the processing sequence '1' to the task 1 (300a) with the earliest deadline, the processing sequence '2' to the task 3 (300c) with the second deadline, and the third Processing order '3' is set for task 4 (300d) having a deadline and processing order '4' is set for task 2 (300b) having the latest deadline, respectively. Accordingly, the processing sequence of the tasks 300 stored in the waiting queue 100 is as shown in (c) of FIG.

When the processing order setting of the task 300 is completed, the scheduler 200 sequentially detects the task 300 stored in the waiting queue 100 according to the processing order and transmits the task 300 to the CPU 400 (S250). That is, the scheduler 200 sequentially detects the task sequence corresponding to the highest priority process from the set task 300 and transmits the same to the central processing unit 400. For example, as shown in (b) of FIG. 8, when four tasks 300 are stored in the waiting queue 100, the scheduler 200 blocks '0' according to processing priority. In addition, tasks 300 stored in blocks '2', '3' and '1' are sequentially detected and transmitted to the CPU 400. Here, the scheduler 200 detects the task 300 at the next position after the processing time of the detected task 300 has elapsed between the task 300 and the task 300. As such, the task scheduling method of the automotive embedded operating system may process the task 300 having an early deadline first, thereby ensuring real-time processing of the task 300.

Thereafter, when the new task 300 is transmitted, the scheduler 200 performs the above-described steps S200 to S250 to schedule the processing sequence of the task 300. As such, according to the second embodiment of the present invention, by specifying the processing sequence number according to the deadline time of the task without changing the task storage location, the first embodiment of the present invention minimizes the processing time according to the change of the storage location of the task There is an effect that can improve the processing speed.

Although a preferred embodiment according to the present invention has been described above, it is possible to modify in various forms, and those skilled in the art to various modifications and modifications without departing from the claims of the present invention It is understood that it may be practiced.

1 is a view for explaining a conventional embedded operating system for automobiles.

2 is a view for explaining the configuration of the task scheduling apparatus of the automotive embedded operating system according to an embodiment of the present invention.

3 is a flowchart illustrating a task scheduling method of an automotive embedded operating system according to a first embodiment of the present invention.

4 to 6 are diagrams for explaining a task scheduling method of an automotive embedded operating system according to a first embodiment.

7 is a flowchart illustrating a task scheduling method of an automotive embedded operating system according to a second embodiment of the present invention.

8 is a diagram for describing a task scheduling method of an automotive embedded operating system according to a second embodiment.

<Description of the symbols for the main parts of the drawings>

100: waiting queue 100a: first waiting queue

100b: second waiting queue 100c: third waiting queue

100d: queue 4 200: scheduler

300: task 300a: task 1

300b: task 2 300c: task 3

300d: task 4 400: central processing unit

Claims (10)

A task scheduling method of an embedded operating system for a vehicle installed to control an electronic device of a vehicle, (a) distributing and storing a task having a deadline according to priority in a plurality of waiting queues having a queue priority; (b) changing a storage location of the tasks in each wait queue based on a deadline of tasks stored in each wait queue; And (c) detecting a task stored in the waiting queue in a storage order. The method according to claim 1, In the step (b), A task scheduling method of an embedded operating system for a vehicle, characterized by changing the task having the earliest deadline to the storage location that is processed fastest. The method according to claim 1, In the step (c), A task scheduling method of an embedded operating system for a vehicle, characterized by detecting a task from a waiting queue having the highest queue priority. A task scheduling method of an embedded operating system for a vehicle installed to control an electronic device of a vehicle, (a) distributing and storing a task having a deadline according to priority in a plurality of waiting queues having a queue priority; (b) comparing the deadlines of one or more tasks stored in the waiting queue to specify a unique processing order number for each task; And (c) detecting a task stored in a waiting queue based on the processing sequence. The method according to claim 4, In the step (b), A task scheduling method of an embedded operating system for a vehicle, characterized by assigning a fastest processing sequence to a task having an earliest deadline. The method according to claim 4, In the step (c), A task scheduling method of an embedded operating system for a vehicle, characterized by detecting the task having the fastest processing sequence. The method according to claim 4, In the step (c), A task scheduling method of an embedded operating system for a vehicle, characterized by detecting a task from a waiting queue having the highest queue priority. The method according to claim 4, (b-1) changing the storage location of the tasks in each wait queue based on the processing order of the tasks stored in each wait queue, In the step (b-1), the task scheduling method of the automotive embedded operating system, characterized in that for changing the task having the fastest processing order to the storage location that is processed fastest. The method according to claim 1 or 4, In the step (a), And storing the task in a waiting queue having a queue priority corresponding to the priority of the task. The method according to claim 1 or 4, In the step (a), The task scheduling method of the embedded operating system for a vehicle, characterized in that the task is distributed to four waiting queues.

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