JP2000047881A - Real-time system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior real-time property by enabling a delicate priority control over input/output processing by determining the priority of processing according to handled input/output data and performing the processing of device drivers according to the priority of the processing. SOLUTION: Device drivers 32 are provided by every input/output devices and drivers 321 and 322 for performing input/output processing using I/O controllers 41 and 42 are provided here. A device driver priority control part 34 requests a scheduler 311 to vary the task priority levels of the input task and output task of the drivers 321 and 322. The scheduler 311 schedules the task of an application program and the input task and output task of the device drivers 32 according to the priority levels given to the respective tasks and executes the tasks. Namely, the task of top priority among executable tasks is selected and executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real-time system, and more particularly, to a real-time system capable of changing the priority of input / output processing by input / output data even when input / output to the same input / output device.

[0002]

2. Description of the Related Art In a real-time system, it is necessary to perform processing in real time in response to an event of a connected input / output device. Therefore, the processing is executed according to the priority using the real-time OS.

[0003] Inputs and outputs to input / output devices are processed by those device drivers. A device driver is provided for each input / output device. For example, as described in Iwanami Shoten, Introduction to ITRON (1988), pp. 38-44, a device driver is executed by an interrupt processing or an input / output processing task. Here, the input / output tasks constituting the driver are executed with the specified priority.

An input / output task is usually executed with a higher priority than a task of an application program. Among the input / output tasks, processing is performed according to the given priority of the input / output task.

[0005] The priority of an input / output task of a device driver handling an input / output device that needs to be executed preferentially is set higher than an input / output task of a device driver handling another input / output device. As a result, the input / output processing of the input / output device that should be executed urgently can be performed before the input / output processing of the input / output device that is not urgently executed, and real-time processing can be easily performed.

[0006]

However, in the above prior art, the priority of input / output processing is uniquely determined for each input / output device. However, depending on the system,
Even with the same input / output device, there are times when it is desired to change the processing priority depending on what the input / output data is. That is, it is desirable to perform input / output processing for data requiring urgency in preference to data not requiring urgency.

For example, when a network is considered as an input / output device, when data flowing on the network, that is, a message is an urgent message, it is desired to perform input / output (transmission / reception) prior to a normal message.

[0008] In addition to the network, RS-232C
I want to give priority to the input / output processing of the RS-232C data over the normal message of the network, but only the emergency message of the network
There is a case where the user wants to give priority to input / output processing of -232C.

However, in the above-mentioned prior art, the above-described processing cannot be performed because the priority of the processing of the device driver is determined for each input / output device.

Accordingly, the present invention provides a real-time system which is capable of changing the priority of processing of a device driver in accordance with input / output data, enabling fine-grained priority control of input / output processing, and having excellent real-time performance. It is intended to provide.

[0011]

In order to achieve the above object, the present invention provides a device driver for handling input / output processing of an input / output device and a device for determining the priority of the processing of the device driver based on the input / output data to be handled. A real-time system is realized by the driver priority control means and the scheduling means for executing the processing of the device driver according to the priority of the processing of the device driver means.

[0012] The device driver priority control means, depending on the type and value of input / output data requested for input / output processing,
The priority of the process of the device driver handling the input / output data is determined. The scheduling means activates and executes the processing of the application program and the device driver in descending order of priority according to their priorities. The device driver is activated by the scheduling and actually executes input / output processing on the input / output device.

Therefore, even for the same input / output device,
Change the priority of the processing of the device driver that handles it according to the type and value of the input / output data requested for input / output,
According to the priority, processing can be performed from the one with the highest priority.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

According to the present invention, data is input from an input / output device,
This is a real-time system in which an application program calculates output data using input data and outputs the output data to an input / output device.

Hereinafter, the present invention will be described in detail with reference to FIGS.

FIG. 1 is a configuration diagram of a real-time system according to an embodiment of the present invention. Real-time system 10
Are a CPU 20, a memory 30, an I / O controller 4
1 and 42, which are connected by a bus 50.

The memory 30 stores an application program 33, a program 31 of an OS kernel, a program group of a device driver 32, and a program of a device driver priority control section 34. In this embodiment, a part that realizes the functions of the OS other than the device driver is called an OS kernel.

The CPU 20 reads out the programs stored in the memory 30 and executes the processing of those programs.

The OS kernel 31 has a scheduler 311,
It includes an inter-task communication processing unit 312, a memory management processing unit 313, and the like. The OS kernel is here, published by Iwanami Shoten, ITRO
The OS described in N Introduction (1988) is used.

The application program 33 includes a plurality of application programs 331, 332, 333, etc.
Each is performed as a separate task. Each task is given a priority, and the scheduler 311 preferentially executes a task with a higher priority according to the priority given to the task.

I / O controllers 41 and 42 control input / output devices connected to the real-time system,
It is hardware that actually performs input / output processing. Examples of the input / output device include a network such as Ethernet or CAN, a serial input / output device such as RS-232C,
There are various devices such as a parallel input / output device, a hard disk device, a floppy disk device, a printer device, and the like.

In order for the application program 33 to perform input / output using the input / output device, the CPU 20 executing the application program 33 needs to perform actual input / output processing using the I / O controllers 41 and 42. . The program for that is the device driver 32.

A device driver 32 is provided for each input / output device. In this example, a driver 321 for performing input / output processing using the I / O controller 41 and an input / output processing using the I / O controller 42 are used. Driver 3
22 are present. It is assumed that a device driver number is given to the drivers 321 and 322.

Here, the device driver is constructed by a method described in Iwanami Shoten, Introduction to ITRON (1988), pp. 38-44.

Next, the input / output processing will be described in detail.

FIG. 2 is a diagram showing a detailed configuration of the device driver 32 and the device driver priority control unit 34 of the present invention.

The driver 321 operates as the input processing handler 32
11, input task 3213, input interrupt handler 321
5, output processing handler 3212, output task 3214,
It consists of a process called an output interrupt handler 3216. The driver 322 has the same configuration. In the following, the input processing handler 3211 and the output processing handler 3212 are collectively referred to as an input / output handler, the input task 3213 and the output task 312.
I / O task, input interrupt handler 32
15 and the output interrupt handler 3216 may be collectively referred to as an input / output interrupt handler.

The device driver priority control section 34 is a program for changing the priority of the input / output task of the device driver 32 according to the type of input / output data. In the present embodiment, the device driver priority control unit 34 is a function (subroutine) called by the input interrupt handler or the output processing handler. The device driver priority control unit 34 controls the input task 3213 and the output task 321 of the driver 321 according to the type of input / output data.
4, the task priority of the driver 322, the input task 3223, and the output task 3224 is requested to the scheduler 311 and changed.

The scheduler 311 schedules and executes the task of the application program, the input task and the output task of the device driver according to the priority given to those tasks. That is, the scheduler selects and executes the task having the highest priority among the executable tasks. When the task being executed ends or is suspended, the task is switched to the task with the highest priority among other executable priorities and executed. Also, if a high-priority task becomes executable during execution of a low-priority task, the execution of the low-priority task is interrupted and the high-priority task is executed. In this embodiment,
The priority is represented by an integer, and the smaller the value, the higher the priority. If there are tasks having the same priority, the tasks are executed in order from the one that became executable first.

A task number is assigned to each task, and a task number can be uniquely specified by specifying the task number.

In FIG. 2, the application program 3
31 calls the driver 321 to execute input / output processing using the I / O controller 41. The input processing handler 3211 is called to execute the input processing, and the output processing handler 3212 is called to execute the output processing. Input handler 3211, Output handler 3212
Is called in the form of a function call, and is executed by the same task 3310 as the application program 331.

Input task 3213, output task 3214
Are executed as independent tasks. The input task and the output task are processed by the scheduler 311 according to the priorities, similarly to the task of the application. In this embodiment, the input task and the output task are given higher priority than the task of the application. The input interrupt handler and the output interrupt handler are activated by an interrupt from the I / O controller. When these interrupts occur, the CPU suspends the processing of the application task and the input / output task, and executes the interrupt processing. Each interrupt has an interrupt level,
The interrupt processing to which the higher priority interrupt level is given is executed with higher priority.

The input interrupt handler 3215 is started by an interrupt from the I / O controller 41 when an input is made to the input / output device. Output interrupt handler 3216
Is activated by an interrupt from the I / O controller 41 when the input / output device has completed the output processing.

The data input / output in this embodiment has a data type, and the data type of the input / output data can be identified by the data type number. In this embodiment, the data type number is included in the input / output data.

The above is about the device driver 321, but the same applies to the device driver 322.

Next, the device driver priority control unit 34
The operation of will be described in detail.

The device driver priority control unit 34 has a function of determining the priority of an input / output task that handles input / output data according to the data type of the input / output data. Therefore, the device driver priority control unit 34 includes a device driver priority table 341 that stores the correspondence between the type of input / output data and the priority of the input / output task when handling the input / output data.

Details of information stored in the device driver priority table 341 will be described with reference to FIG. The device driver priority table 341 includes an area 3411 for storing a driver number of each device driver, and a task number 3 of an input task and an output task of each device driver.
For each input data and output data of each device driver, there is an area 3413 for storing the data type number of the data, and an area 3414 for storing the priority of the input / output task corresponding to the data type number. .

Here, the driver number of the driver 321 is 1, the task number of the input task 3213 is 11, the task number of the output task 3214 is 12, the driver number of the driver 322 is 2, the task number of the input task is 21, and the output task is Has a task number of 22. The driver 32
The data type numbers of input / output data handled by 1 are 101 to 1
05, the data identification numbers of the input / output data handled by the driver 322 are 201 to 205.

In FIG. 3, for example, when the driver 321 inputs data of the data type number 101, the priority of the input task 3213 is 2, and when the driver 321 outputs data of the data type 102, the priority of the output task 3214 is 7 The priority of the input task 3223 when the driver 322 inputs data of the data type 203 is 12.

The device driver priority control unit 34 is a function (subroutine), as shown in FIG. 2, when called by the input interrupt handlers (3215, 3225) (32151, 32251), 3212, 3222) (32121, 32221). The data type and the task number of the input / output task are passed as arguments. Also,
The scheduler 311 is requested to change the priority of the input / output task (3401).

The flow of processing of the device driver priority control section 34 will be described with reference to FIG. The device driver priority control process 200 first reads the device driver priority table 341 and determines the priority corresponding to the data type and the input / output task number given by the argument (process 201). Next, the scheduler 311 is requested to change the priority of the task of the input / output task number to the determined priority (process 202), and the process returns.

As described above, the device driver priority control unit 34 changes the priority of the input / output task according to the data type of the input / output data.

Next, the operation of the input processing handler 3211 will be described. The input processing handler is a function called by the application.

For example, as shown in FIG. 2, the input processing handler 3211 is called by the application program 331 (32131), and the input request buffer 321
01 to the input task 3213 (3
2111), the input response from the input task 3213 is read from the output request buffer 32102 (32112), and the process returns (32132). Although the figure is called from the application program 331, it may be called from the application program 332 or another application.

The flow of processing of the input processing handler will be described with reference to FIG. The processing 1000 of the input handler is, first,
The input request is written into the input request buffer (1001).
Next, the input response corresponding to the input request is read from the input response buffer, and the process waits until the input response is given to the input response buffer (process 1002). When an input response is given, the input response is read from the input response buffer (process 1003). Since the input response includes the input data, the input data is returned (step 100
4).

The operation of the input processing handler 3221 is the same.

Next, the operation of the input task 3213 will be described. The input task is an independent task and is started when the system is started.

As shown in FIG.
Reads the input request from the input request buffer 32101 (32116), and waits for data input to enter a standby state. Then, in response to the release of standby from the input interrupt handler 3215 (32112), the input data buffer 32
The input data is read from 105 (32120), and an input response including the input data is written to the output request buffer 32102 (32112).

The processing flow of the input task 3213 will be described with reference to FIG. The process of the input task 3000 first waits until an input request is given to the input request buffer (process 3
001). When an input request is given, the input request is read from the input request buffer (step 3002), and a system call of the OS to enter the standby state is called to enter the standby state (step 3003). When the standby state is released, the input data is read from the input data buffer (step 300).
4) The input response is written into the input response buffer (process 3005), and the process returns to the input request wait (process 3001).

The operation of the input task 3223 is the same.

Next, the operation of the input interrupt handler 3215 will be described. The input interrupt handler is an interrupt process.

As shown in FIG. 2, the input interrupt handler 3
215 is an interrupt 321 from the I / O controller 41
It is activated by 41. When activated, it takes in input data from the I / O controller (32142), determines the data type of the input data, and calls the device driver priority control unit 34 (32151). Then, the input data is stored in the input data buffer 32105 (32
121), the input task 3213 is released from standby (32)
122).

The flow of processing of the input interrupt handler will be described with reference to FIG. When the process 5000 of the input interrupt handler is activated, first, data is input from the I / O controller 41 (process 5001). Next, the data type of the input data is determined (process 5001), and the device driver priority control unit 34 is called using the data type and the task number of the input task 3213 as arguments (process 5003). Then, the input data is stored in the input data buffer (process 5004), a system call of the OS for releasing the task standby state is called, the input task 3213 is released from the standby state (process 5005), and the process ends.

The operation of the input interrupt handler 3225 is the same.

Next, the operation of the output processing handler 3212 will be described. The output processing handler is a function called by the application.

For example, as shown in FIG. 2, the output processing handler 3212 is called by the application program 331 (32133), determines the data type of the output data, and calls the device driver priority control unit 34 (32121). , Writes an output request to the output task 3214 in the output request buffer 32103 (32113),
The output response from the output task 3214 is output to the output buffer 32.
Read from the memory 104 (32115) and return (3
2134). Although the figure is called from the application program 331, the application program 3
32 or may be called from another application.

The processing flow of the output processing handler will be described with reference to FIG. The process 2000 of the output handler firstly
The data type of the output data is determined (process 2001),
The device driver priority control unit 34 is called using the data type and the task number of the output task 3214 as arguments (process 2002). Next, an output request is written to the output request buffer (2003). Then, an output response corresponding to the output request is read from the output response buffer, and the process waits until the output response is given to the output response buffer (process 2004). When the output response is given, the output response is read from the output response buffer (process 2005).
It returns (processing 2006).

The operation of the output processing handler 3222 is the same.

Next, the operation of the output task 3214 will be described. The output task is an independent task and is started when the system is started.

As shown in FIG.
Reads out the output request including the output data from the output request buffer 32103 (32118), outputs the data to the I / O controller (32143), and temporarily enters a standby state waiting for the end of the output processing. Then, in response to the release of the standby state from the output processing interrupt handler 3216 (32116), the output response indicating the completion of the output is output to the output response buffer 3210.
4 (32119).

The processing flow of the output task 3214 will be described with reference to FIG. The process of the output task 4000 first waits until an output request is given to the output request buffer (process 4).
001). When an output request is given, the output request is read from the output request buffer (process 4002), and the output data included in the output request is output to the I / O controller (process 4003). Next, a system call of the OS to enter the standby state is invoked to enter the standby state (process 4004). When the waiting state is released, the output response is written into the output response buffer (step 4005), and the output request is waited (step 40).
01).

The operation of the output handler 3222 is the same.

Next, the operation of the output interrupt handler 3216 will be described. The input interrupt handler is an interrupt process.

As shown in FIG. 2, the output interrupt handler 3
216 is activated by an output end interrupt 32144 from the I / O controller 41. When activated, the output task 3214 is released from standby (32126).

The processing flow of the output interrupt handler will be described with reference to FIG. When activated, the process 6000 of the output interrupt handler calls a system call of the OS for canceling the standby state of the task, cancels the standby state of the output task 3214 (process 6001), and ends.

The operation of output interrupt handler 3226 is similar.

The operation of the embodiment of the present invention has been described above.

In one embodiment of the present invention, for example, in FIG. 2, the application program 331 calls the input processing handler 3211 and the application program 332 calls the input handler 3221 to request the input processing, and the input task 3213 is input. Task 3223
, Respectively, start processes corresponding to the input processing requests and enter a standby state. It is assumed that the task of the application program 333 is being executed. The priority value of the application program 331 and the priority value of the application program 332 are the same, and the priority value of the application program 333 is larger than the priority value of the application programs 331 and 332 (that is, the priority value is lower).

In this state, the I / O controller 41 and the I / O controller 41
Consider a case where data is input to the / O controller 42 at the same time. First, the input interrupt handler 3215 and the input interrupt handler 3225 are activated and processed. In these interrupt processes, the one with the higher priority according to the given interrupt level ends first, but in any case, the task of the application program 333 is interrupted and the interrupt process is executed.

When the interrupt processing is completed, the input task 3213 and the input task 3223 can be executed.
Those tasks are executed with higher priority first. However, the priority changes depending on the type of input data.

As shown in FIG. 3, the input task 3213
Are 2 when inputting data of data type 101, 6 when inputting data of data type 102,
It is 8 when data of other data types is input. The priority of the input task 3223 is the data type 201
Is set to 4 when data of the data type 202 is input, and is set to 12 when data of the other data type is input.

Therefore, for example, when data of the data type 101 is input to the I / O controller 41 and data of the data type 201 is input to the I / O controller 42, the processing of the input task 3213 is performed by the input task 313.
223 is executed prior to the process. Accordingly, since the task of the application program 331 can be executed before the task of the application program 332, the task of the application program 331 is executed before the task of the application program 332.

On the other hand, the data of the data type 102 is input to the I / O controller 41 and the I / O controller 42
When data of the data type 201 is input to the input task 3223, the processing of the input task 3223 is executed in preference to the processing of the input task 3213. Accordingly, since the task of the application program 332 can be executed before the task of the application program 331, the task of the application program 332 is executed before the task of the application program 331.

The embodiment of the present invention has been described above in detail. According to the present invention, as described above, even if the input is to the same I / O controller, the priority of processing can be changed depending on the data type of the input / output data. In other words, data requiring urgency can be subjected to input / output processing prior to data that does not require urgency, and this has the effect of realizing a real-time system with excellent real-time properties.

Up to now, the data type number of the input / output data has been included in the input / output data. However, the data type may be determined based on the value range of the input / output data. Further, the data type may be determined based on control information for performing input / output, instead of the input / output data itself.
For example, in the case of a network, the data type may be determined based on the destination address. This eliminates the need to include the data type number in the input / output data, and has the effect of improving efficiency.

In the present invention, the input handler waits for processing until an input response is obtained, but may return without waiting. In this case, a response indicating that the input could not be performed is returned to the application. This has the effect that the processing of the application is not interrupted and the processing can be executed quickly.

In the present invention, the output handler waits until the output response is obtained, but may return without waiting. This has the effect that the processing of the application is not interrupted and the processing can be executed quickly.

In the present invention, the priority of the input / output task is changed according to the type of data. However, the interrupt level of the input / output interrupt handler may be changed according to the type of data.
In this case, the processing of the input / output interrupt handler according to the interrupt level is determined by hardware and executed. As a result, the priority of the interrupt handler process can also be changed according to the data type, and the interrupt handler process can be executed, so that there is an effect that finer priority control of the input / output process can be performed. Also, there is an effect that the processing is made more efficient.

In the present invention, the device driver is composed of the input / output interrupt handler, the input / output task, and the input / output processing handler. However, it is assumed that the input interrupt handler executes the processing of the same function as that of the input task. You may delete the task. This has the effect of simplifying the configuration of the device driver and facilitating mounting.

In the present invention, the device driver is composed of an input / output interrupt handler, an input / output task, and an input / output processing handler. However, the output processing handler executes processing having the same function as that of the output task. May be deleted. This has the effect of simplifying the configuration of the device driver and facilitating mounting.

[0083]

According to the present invention, the priority of the device driver process is determined by the device driver priority control means.
It changes according to the type and value of the input / output data, enables fine-grained priority control of input / output processing according to the input / output data, and has an effect that a real-time system excellent in real-time property can be easily realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a real-time system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a portion related to input / output processing according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a device driver priority table according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a process flow of device driver priority control according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating a flow of processing of an input processing handler according to an embodiment of the present invention.

FIG. 6 is a flowchart illustrating a flow of processing of an input task according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a flow of an input interrupt handler according to one embodiment of the present invention.

FIG. 8 is a flowchart illustrating a flow of processing of an output processing handler according to an embodiment of the present invention.

FIG. 9 is a flowchart illustrating a flow of processing of an output task according to an embodiment of the present invention.

FIG. 10 is a flowchart showing a flow of an output interrupt handler according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Real-time system, 20 ... CPU, 30 ... Memory, 41, 42 ... I / O controller, 31 ... OS kernel, 32 ... Device driver, 33 ... Application program, 34 ... Driver priority control part, 311
... Scheduler, 312 ... Inter-task communication processing unit, 313
... Memory management processing unit, 321, 322.
1,332,333 ... application program, 3
41: Device driver priority table, 3211, 3
221, input processing handlers, 3212, 3222, output processing handlers, 3213, 3223, input tasks, 321
4, 3224: output task, 3215, 3225: input interrupt handler, 3216, 3226: output interrupt handler, 32101, 32201: input request buffer, 32
102, 32103 ... output request buffer, 32103,
32203: output request buffer, 32104, 3220
4: Output response buffer, 32105, 32205: Input data buffer.

Continued on the front page (72) Inventor Hidemitsu Naya 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi, Ltd. F-term (reference) 5B014 FB03 5B098 AA05 BB05 CC05 GA04 GC03 GC03

Claims (7)

[Claims] A memory for storing a program; a CPU for executing the program stored in the memory; and an I / O controller for controlling an input / output device to input and output data. A real-time system that executes processing of an application program stored in the memory while performing input and output of data using the
Device driver means for performing input / output processing using the I / O controller; device driver priority control means for determining the priority of processing of the device driver means in accordance with the type of input / output data to be handled; A real-time system having scheduling means for executing device driver processing according to the processing priority of the means. 2. The real-time system according to claim 1, wherein said device driver includes an input task for performing input processing, and said device driver priority control means determines a priority of said input task according to a type of input data. ,
A real-time system wherein the scheduling means executes the processing of the input task according to the priority of the input task. 3. The real-time system according to claim 1, wherein said device driver includes an output task for performing output processing, and said device driver priority control means determines a priority of said output task according to a type of output data. A real-time system in which the scheduling means executes the processing of the output task according to the priority of the output task. 4. The real-time system according to claim 1, wherein said device driver includes an input interrupt handler started by an interrupt of said I / O controller, and said device driver priority control means operates in accordance with a type of input data. A real-time system in which an interrupt level of the input interrupt handler is determined, and the scheduling means is implemented by hardware that executes processing of the input interrupt handler according to the interrupt level of the input interrupt handler. 5. The real-time system according to claim 1, wherein said device driver includes an output interrupt handler activated by an interrupt of said I / O controller, and said device driver priority control means operates according to a type of output data. A real-time system wherein the interrupt level of the output interrupt handler is determined, and the scheduling means is realized by hardware for executing the processing of the output interrupt handler according to the interrupt level of the output interrupt handler. 6. The real-time system according to claim 1, wherein the data type of the input / output data is:
A real-time system that determines the range of input / output data values. 7. The real-time system according to claim 1, wherein at least one of said input / output devices is a network, and a data type of said input / output data is determined by an address of a transmission / reception destination of said input / output data. Real-time system.