JP2760721B2 - Computer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system in which a plurality of tasks are executed, and more particularly to a computer system having a function of managing and scheduling a plurality of tasks having a specific execution cycle and execution time. is there.

[0002]

2. Description of the Related Art FIG. 15 is a block diagram of a part related to scheduling of a computer system provided in, for example, "MELTAS JP-EIS / W Construction Manual for Mitsubishi Electric Integrated Control System" (published the first edition in May 1991). It is.

First, the concept of periodic scheduling will be described with reference to FIG. The minimum reference cycle in the figure is a reference cycle for periodically checking task activation, and is a minimum cycle for scheduling application tasks 1 to L (L is the number of tasks) to be executed periodically. is there. The time slot is a time unit obtained by dividing the minimum reference cycle by a predetermined value N (determined by the user according to the system), and the scheduler selects the execution tasks 1 to L for each time slot time. The execution level is a set of a plurality of tasks in which the execution tasks 1 to L are classified for each cycle.
M is assigned (the assignment method will be described later). When executing the scheduling, the scheduler preferentially executes the task waiting for activation of the execution level assigned to the time slot in a certain time slot (an execution level selection method will be described later).

In the example shown in FIG. 16, an execution level 1 is assigned to time slot 1 and time slot 2, an execution level 2 is assigned to time slot 3, and an execution level M is assigned to time slot (N-1). A spare time slot (α) for the system time required for each time slot processing , and an execution level 1 is assigned as the execution level selection time and the time slot calculation time. Two tasks, task 1 and task 2, belong to execution level 1, task 3 belongs to execution level 2, and task L belongs to execution level M. At the time of scheduling, a time slot calculator described later calculates a time slot value from the value of the timer. For each minimum reference cycle, the execution
The task of the bell is executed by the activation task queuing unit described later.
Start request, but different run levels start at the same time
If requested, activation is required for each time slot as follows:
The request execution level is switched. In time slot 1, execution level 1 is selected, and task 1 of execution level 1 is being executed. In the time slot 2, the execution level 1 is selected, and the task 1 is executed similarly. In the time slot 3, the execution level 2 is selected, and the task 3 belonging to the execution level 2 is executed.
Since the time slot N is a spare time slot, an unexecuted task is executed within the minimum reference cycle. The execution level selection as described above is repeated every minimum reference cycle.

[0005] In FIG. 15, reference numeral 11 denotes a task classified into execution levels from task information 12 including a unique execution cycle and execution time for each task provided by a user, and includes information on a time slot to which the execution level is assigned. A time slot allocating unit that generates table information (change value) 23 and stores the table information 23 in the time slot corresponding task information table 21, as shown in FIG.
An execution cycle determining means 11a for determining an execution cycle of each task from the task information 12, a classification means 11b for classifying each task from an execution level having a short execution cycle to a long execution cycle based on a result of the determination; It comprises time slot allocating means 11c for allocating an execution level. On the other hand, 13 in FIG. 15 is triggered by a time slot change interrupt 17 from a time slot calculation unit 16 described later, and
A scheduling execution unit for selecting an execution task based on table information (current value) 22 from 1 and a time slot value (current value) 20 from a time slot information storage unit 18 described later, and activating the task. The software (hereinafter, abbreviated as S / W), which is a function, is started by a periodic interrupt 15 from a timer 14, calculates a time slot value (change value) 19 from the current time, and stores it in the time slot information storage unit 18. A time slot calculation unit that writes the value and, when the time slot information is changed, interrupts the scheduling execution unit 13 with a time slot change interrupt 17 to interrupt the current task execution and allows the scheduling execution unit 13 to select the activation task. , The calculated time slot value is also held internally, Tsu capital value is incremented as the previous value of the time slot at the time of the calculation of the next time. 24 is
The activation request task 25 passed from the user as the task information 12 is stored in the time slot corresponding task information table 21.
Is a startup task queuing unit that queues in a queue (queue) generated by a task management table described later.

FIG. 18 is a detailed diagram of each table included in the time slot corresponding task information table 21 of FIG. A time slot management table 211 stores information on execution levels 1 to M assigned to each of the time slots 1 to N, and 212a to 212c stores a queuing state of a task of each execution level assigned to each time slot value. Level management table 213a1 to 213a
n, 213b1, 213c1, and 213c2 are task management tables for generating the above-described queues. The time slot management table 211 stores pointers a to c indicating the addresses of the level management tables 212a to 212c corresponding to the execution levels 1 to M assigned to the time slots 1 to N, respectively. The time slot N is a spare time slot (α) for the system time, and is assigned an execution level 1 to preferentially execute a task with a small execution level. Task management tables 213a1 to 213a21
A pointer 3c2 indicates the address of the next task management table (however, the pointers of the last task management tables 213an, 213b1, and 213c2 in the queue are NULL pointers indicating that there is no following table).
And information of the activation task. In the level management tables 212a to 212c, a pointer indicating the address of the task management table at the head of the queue at each execution level and a pointer indicating the address of the task management table at the end are stored. For example, level 1
A pointer a1 indicating the address of the head task management table 213a1 of the queuing task belonging to the execution level 1 and a pointer an indicating the address of the tail task management table 213an of the queuing task belonging to the execution level 1 are stored in the level management table 212a. , Provides information that the tasks shown in these task management tables 213a1 to 213an are tasks waiting to be executed.

Next, the operation will be described. First, means for allocating the execution level to the time slot management table 211 by the time slot allocating unit 11 will be described with reference to the flowcharts of FIGS. Prior to the assignment, based on the input task information 12, the execution cycle determining unit 11a and the classifying unit 11b execute M activation tasks for each execution cycle (the number determined by the user based on the number of execution tasks and the capacity of the system). ) (ST191). Next, the time slot allocating means 11
According to c, the following processing is repeated for execution levels 1 to M (ST192). First, for the execution level 1, the total of the execution times in the minimum reference cycle unit is obtained by multiplying the sum of all the task execution times belonging to the execution level 1 by the ratio of the execution cycle of the execution level 1 to the minimum reference cycle. (ST193). For example, when the execution cycle of the task of execution level 1 is 100 ms, the total execution time of the task of execution level 1 is 40 ms, and the minimum reference cycle is 50 ms, 40
× (50/100) = 20 ms is the value to be obtained. That is, the execution level 1 requires an execution time of 20 ms within the minimum reference cycle. The result is divided by the time slot time, rounded up to the decimal point, and the number of time slots required for execution level 1 within the minimum reference cycle is obtained (ST194).
In the above example, when the time slot time is 10 ms, 2
0/10 = 2, so two time slots are required. The above processing is similarly repeated from execution levels 2 to M (ST195), and the number of time slots required for each execution level is obtained. Next, the number of time slots required for the execution time of the system required to execute the task within the minimum reference period is obtained by dividing the system execution time by the time slot time and rounding up the decimal point (ST196). Above,
Each execution level and the number of time slots required by the system can be calculated. However, if the total exceeds the number N of time slots of the minimum reference period, the maximum execution load is exceeded and scheduling becomes impossible. The number N of time slots in the reference cycle is compared (ST197), and if the total is greater than the number N of time slots, pointers to the level management table are shifted from execution level 1 by the required number of time slots to time slot management table 2 in order.
11 and when the time slot management table 211 is satisfied, the remaining levels are ignored (S
T199). If the total is smaller than the number N of time slots, the time slots are stored in the time slot management table 211 in order from the execution level 1 (ST198). This completes the assignment of the execution level to the time slot.

Next, a scheduling method by the scheduling execution unit 13 using the time slot management table 211 will be described with reference to a flowchart of FIG. S
In response to the fixed-period timer interrupt 15 from the / W timer 14, the time slot calculator 16
Is calculated, the value is stored in the time slot information storage unit 18, and the time slot change interrupt 17 is output to the scheduling execution unit 13. Scheduling execution unit 13
Receives the change interrupt 17 and starts operation. The current time slot value 20 is stored in the time slot information storage 1
8 (ST211), and the execution levels assigned to the obtained time slot values are obtained from the execution levels 1 to M of the time slot management table 211 in FIG. 18 (ST212). The existence of a task (task waiting to be executed) queued at the execution level is checked using the level management tables 212a to 212c (ST21).
3) If it is queued, execute the first task (ST214). For example, when the time slot value from the time slot information storage unit 18 is 1, the scheduling execution unit 13 uses the time slot management table 211 to indicate the level management table 212a indicated by the pointer a.
And executes the task of the head task management table 213a1 indicated by the pointer a1. If not queued, the execution level is incremented (S
T216), the queuing state check is repeated for the level management table of the next execution level. Since the execution level is checked cyclically as shown in FIG. 22 starting with the execution level assigned to the current time slot, the execution level is returned to 1 when the execution level exceeds M (ST217, ST218). When all the execution levels have gone through the above check (ST219), it is determined that there is no execution task in all the execution levels (ST220). When there is an execution task or no execution task, the process waits for the time slot change interrupt 17 (ST215), returns to the acquisition of the next time slot value, and repeats the above operation.

[0009]

Since the conventional computer system is configured as described above, the time slot allocation method shown in FIGS. 19 and 20 reduces the load on the processor by performing periodic scheduling. Evenly, the task can be periodically checked for the task activation at the minimum reference cycle, so that periodic scheduling less than the minimum reference cycle becomes impossible. For this reason, there is a problem that the user has to determine an execution cycle of a task having an execution cycle shorter than the minimum reference cycle so that such a task does not exist. Also, since only the execution request task specified by the user in advance, that is, the task assigned to the time slot management table, can be executed, it is not possible to perform the non-periodic interrupt processing such as the error processing together with the periodic task. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In addition to the conventional periodic scheduling, the present invention provides a scheduling when there is a task whose execution cycle is less than a minimum reference cycle. It is an object of the present invention to obtain a computer system capable of scheduling tasks having a period of. Also, along with periodic tasks,
It is an object of the present invention to obtain a computer system that also enables non-periodic interrupt processing such as error processing.

[0011]

According to a first aspect of the present invention, there is provided a computer system having a function of managing and scheduling a plurality of tasks each having a unique execution cycle and execution time. An execution cycle determining means for determining an execution cycle of the task; a classification means for classifying each task from an execution level having a short execution cycle to a long execution level based on the determination result of the execution cycle determining means; Time slot allocating means for allocating the execution level to a time slot, which is a time unit obtained by dividing a minimum reference cycle as a reference when checking by a predetermined value, and an execution cycle of an execution level in which tasks of the minimum execution cycle are classified Means for determining whether is shorter than the minimum reference cycle, and a preset value based on the comparison result.
A scheduling mode switching means for switching between a periodic scheduling mode for allocating the execution level to each time slot and a priority scheduling mode for allocating an execution level in which tasks having a minimum execution cycle are classified to all time slots,
Scheduling execution means for executing task scheduling from the execution level assigned to the time slot corresponding to the current time, wherein the execution cycle of the execution level in which the task of the minimum execution cycle is classified by the comparison means is smaller than the minimum reference cycle. When it is determined that the time is short, the scheduling mode switching means switches from the normal periodic scheduling mode to the priority scheduling mode, and based on this, the time slot allocating means classifies the tasks having the minimum execution period into all the time slots. An execution level is assigned.

Further, a computer system according to a second aspect of the present invention provides an execution cycle determining means for determining an execution cycle of each task, and based on a result of the determination by the execution cycle determining means, executes each task from an execution level having a short execution cycle. A classifying means for classifying the execution level to a long execution level, and a time slot assignment for assigning the execution level to a time slot which is a time unit obtained by dividing a minimum reference cycle as a reference for periodically checking task activation by a predetermined value. Means, and scheduling execution means for executing task scheduling from an execution level assigned to a time slot corresponding to the current time, and notifying the scheduling execution means of the occurrence of an aperiodic event such as an error by interruption. Interrupt generating means and interrupt processing means for performing processing when the above-mentioned interrupt occurs. In addition, the scheduling execution means, when the interrupt occurs, when the priority of the periodic task and the interrupt processing is higher than the periodic task based on the priority of the predetermined periodic task and the interrupt processing, that is, when the priority of the periodic task is higher than the priority of the periodic task, The execution is temporarily suspended, and the interruption processing means is caused to execute the interruption processing.

On the other hand, a computer system according to a third aspect of the present invention provides an execution cycle determining means for determining an execution cycle of each task and a task based on the determination result of the execution cycle determining means, as in the first invention. Classification means for classifying the execution level from a short execution level to a long execution level, and a time slot which is a time unit obtained by dividing a minimum reference cycle as a reference when periodically checking task activation by a predetermined value, Time slot allocating means for allocating an execution level, comparison means for determining whether or not the execution cycle of the execution level in which the tasks of the minimum execution cycle are classified is shorter than the minimum reference cycle, and a preset time slot based on the comparison result. Lap
A scheduling mode switching means for switching between a periodic scheduling mode for assigning the execution level to each time slot according to a period, and a priority scheduling mode for assigning an execution level in which tasks of the minimum execution cycle are classified to all time slots; And a scheduling execution means for executing task scheduling from an execution level assigned to a time slot corresponding to the time slot, and generating an interrupt to the scheduling execution means for each time slot time based on a clock from a hardware timer. When,
A counter that counts each time slot value based on a clock from a hardware timer, and a time slot value is set by the counter. Each time an interrupt is generated from the interrupt generator, the time slot value at the current time is set by the scheduling execution unit. A register to be read out, and when it is determined by the comparing means that the execution cycle of the execution level at which the task of the minimum execution cycle is classified is shorter than the minimum reference cycle, the scheduling mode switching means performs the normal periodic scheduling mode. To the priority scheduling mode, based on which the time slot allocating means allocates an execution level in which the tasks of the minimum execution cycle are classified to all the time slots.

[0014]

In the computer system according to the first aspect of the present invention, before the time slot allocating means executes the time slot allocation at the execution level, the execution cycle determining means, the classifying means and the comparing means execute the execution cycle less than the minimum reference cycle. Check for the existence of the task. If present,
Scheduling mode switching means switches from the normal periodic scheduling mode to the priority scheduling mode. When recognizing that the scheduling mode is the priority scheduling mode, the time slot allocating means allocates the execution level of the minimum execution cycle to all the time slots. The scheduling execution means executes tasks in all time slots in order from the execution level of the assigned minimum execution cycle. By assigning the execution level of the minimum execution cycle to all time slots, tasks are always checked in order from the execution level of the minimum execution cycle, and as a result, the execution level of the minimum execution cycle is given the highest priority and the time is given. Priority scheduling that checks task activation in slot units is realized.

Further, in the computer system according to the second invention, the scheduling execution means checks for the presence or absence of an interrupt from the interrupt generation means, and if there is no interrupt, performs normal periodic scheduling. If there is an interrupt, based on the priority of the periodic task and the interrupt processing, if the priority of the interrupt processing is high, the interrupt processing means is caused to perform the interrupt processing. If the priority of the interrupt processing is low, normal periodic scheduling is performed. As a result, it is possible to control the periodic scheduling and the priority of interrupt processing that occurs aperiodically, such as error processing.

On the other hand, in the computer system according to the third aspect of the present invention, the interrupt generator and the counter operate according to the clock from the hardware timer, and the interrupt generator generates an interrupt from the interrupt generator to the scheduling execution means at every time slot time. , The time slot value of each time is set in the register. The scheduling execution means goes to a register when an interrupt occurs for each time slot time, and obtains a time slot value corresponding to the current time. Using this time slot value, the same scheduling processing as in the first invention is performed. By using a hardware timer for the timer and automatically setting the time slot value in the register, the load on the system can be reduced and the processing speed can be improved.

[0017]

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a part related to scheduling of the computer system according to the first embodiment. In the figure, reference numeral 26 denotes a newly provided scheduling mode selection unit, which checks, from the task information 12, whether or not there is a task shorter than the minimum reference cycle during the execution cycle of the activation task, and if there is, the priority mode is set as the scheduling mode. Select the mode, and if not, select the conventional periodic scheduling mode. Reference numeral 27 denotes a scheduling mode signal output by the scheduling mode selection unit 26 as a selection result. 11 receives a scheduling mode signal 17 from the scheduling mode selector 26, performs the same operation as the conventional one in the case of the periodic scheduling mode, and assigns the execution level 1 to all the time slots in the case of the priority scheduling mode. This function is realized by the time slot allocating means 11c shown in FIG. Others are the same as the conventional system.

FIG. 2 is a functional block diagram showing the internal configuration of the scheduling mode selector 26. In the figure, reference numeral 26a denotes an execution cycle determining means for determining the execution cycle of each task based on the task information 12, and 26b designates each task from an execution level having a short execution cycle to a long execution level based on the determination result of the execution cycle determining means 26a. Classifying means for classifying the tasks to levels up to 26c; comparing means for determining whether or not the execution cycle of the execution level at which the task of the minimum execution cycle is classified by the classification means 26b is shorter than the minimum reference cycle;
26d is a scheduling mode switching means for switching between a conventional periodic scheduling mode and a priority scheduling mode for assigning an execution level in which a task having the minimum execution cycle is classified to all time slots as a new scheduling mode based on the comparison result. The output of the scheduling mode switching means 26d becomes the scheduling mode signal 27. Note that the execution cycle determining means 26a and the classifying means 26
b is an execution period discriminating means 11a and a classifying means 11b (FIG. 1) conventionally provided in the time slot allocating unit 11.
7). Therefore, it is also possible to provide only one set of these and share them between the time slot assignment unit 11 and the scheduling mode selection unit 26.

Next, a method of allocating a time slot according to the present embodiment will be described with reference to flowcharts shown in FIGS. First, the scheduling mode selection unit 26 determines the execution cycle of all activated tasks by the execution cycle determination unit 26a, and classifies the execution tasks into execution levels by execution cycle by the classification unit 26b (ST31). For example, an execution cycle of 50 ms
Are classified into an execution level 1, tasks with an execution period of 70 ms are classified into an execution level 2, and so on. Next, the scheduling mode selecting unit 26 compares the execution cycle of the execution level 1 to which the task of the minimum execution cycle belongs with the minimum reference cycle by the comparing means 26c (ST32). If the cycle of the execution level 1 is smaller, The priority scheduling mode is selected by the scheduling mode switching means 26d (ST34), and if it is larger, the same periodic scheduling mode as the conventional one is selected. (ST33).
Next, the time slot allocating unit 11 receives the scheduling mode signal 27 and checks this mode (ST35). If this mode is the priority scheduling mode, as shown in FIG. The execution level 1 is assigned to the slots 1 to N (ST36). When the scheduling mode is the periodic scheduling mode, the same processing as in the conventional system is performed. That is, the time slot allocating unit 11 performs the following processing for the execution levels 1 to M (ST37). For execution level 1, by multiplying the sum of all task execution times of execution level 1 by the ratio of the execution cycle of execution level 1 to the minimum reference cycle,
The time that the total execution time of the task of the execution level 1 occupies in the minimum reference cycle is obtained (ST38). As described in the conventional example, for example, when the execution cycle of a task of execution level 1 is 1
00 ms, total execution time of task of execution level 1 is 40
ms, when the minimum reference cycle is 50 ms, 40 × (50/1
00) = 20 ms is the value to be obtained. That is, the execution level 1 requires an execution time of 20 ms within the minimum reference cycle. The result is divided by the time slot time, rounded up below the decimal point, and the number of time slots required for the execution level 1 within the minimum reference cycle is obtained (ST39). In the above example, when the time slot time is 10 ms, 20/10 = 2, so two time slots are required. The above processing is similarly repeated from execution levels 2 to M (ST40), and the number of time slots required for each execution level is obtained. Next, the number of time slots required for the execution time of the system required for executing the task is obtained (ST41). As described above, the number of time slots required by each execution level can be calculated. However, if the total exceeds the number N of time slots in the minimum reference cycle, the execution maximum load is exceeded and control becomes impossible. N are compared (ST42), and if the total exceeds the number N of time slots, the required number of time slots is stored in the time slot management table 211 in order from the execution level 1; Is ignored (ST44). If N is larger, there is no problem and it is stored in the time slot management table 211 in order from the execution level 1 (ST43). This completes the assignment of the execution level to the time slot.

The execution of the scheduling after the allocation of the time slot performs the same operation as the conventional means. At this time, when the time slot management table 211 is generated in the priority scheduling mode as shown in FIG. 5, the flow chart of FIG. 21 shown in the conventional example becomes as shown in FIG. The execution level 1 is obtained ( ST221 ), the level management tables 212a to 212c are checked from the execution level 1 according to FIG. 22, and the queuing task found first is executed. As a result,
Execution level 1 is given the highest priority, and execution level M is given the lowest priority. That is, the execution level 1 is obtained in any time slot and the execution task is determined according to the execution level search shown in FIG. 22.
Large tasks are not executed. As a result, priority scheduling is realized, in which a task with a lower execution level is given a higher priority. In this case, FIG. 16 shown in the conventional example becomes as shown in FIG.

Embodiment 2 FIG. FIG. 8 is a configuration diagram of a portion related to scheduling of the computer system according to the second embodiment. This embodiment is different from the first embodiment in FIG. 1 in that an interrupt generation unit 28 that notifies the scheduling execution unit 13 of the occurrence of an aperiodic event such as an error by an interrupt, and an interrupt that performs processing when an interrupt occurs. A processing unit 29 and a priority information storage unit 30 for storing priority information between a predetermined periodic task and the interrupt processing are provided. Then, the scheduling execution unit 1
3 normally performs the periodic scheduling as in the first embodiment, and when an interrupt (including an interrupt type) 31 is received from the interrupt generation unit 28 due to an error or the like, the priority information 32 from the priority information storage unit 30 If the priority of the interrupt processing is higher than that of the periodic task, the interrupt processing request (including the type of interrupt) 3
3 is sent to the interrupt processing unit 29, and the execution of the periodic task is temporarily interrupted to execute the interrupt processing.

As shown in FIG. 9, the interrupt generation section 28 has an interrupt type notification table 28a, an interrupt generation notification table 28b, and an execution task monitoring section 28c. explain. If any error occurs in the task during execution of the computer system, the task 28d writes the interrupt type 28e in the interrupt type table 28a and sets the interrupt generation signal 28f in the interrupt generation notification table 28b. on the other hand,
The execution task monitoring unit 28c sets the interrupt occurrence notification table 2
When the interrupt generation signal 28g from the table 28b is set, an interrupt type 28h is obtained from the interrupt type notification table 28a and sent to the scheduling execution unit 13 by the interrupt 31. After the processing is completed, the interrupt occurrence notification table 28b is again
Enter polling. On the other hand, the interrupt processing unit 29
As shown in FIG. 10, the interrupt type notification table 29a
And an interrupt processing request notification table 29b, an interrupt handler 29c, and a plurality of interrupt processing routines (1) 29d to (n) 29f corresponding to interrupt types.
Upon receiving the interrupt 31 including the interrupt type from the interrupt generating unit 28, the scheduling execution unit 13 compares the priority of the interrupt process corresponding to the interrupt type with the priority of the periodic task, and if the priority of the interrupt process is higher, The interrupt type 33b is written in the interrupt type notification table 29a of the interrupt processing unit 29, and then the interrupt processing request 33a is set in the interrupt processing request notification table 29b. On the other hand, the interrupt handler 29c
Polls the interrupt processing request notification table 29b at regular intervals, and if an interrupt processing request 29g from the table 29b is set, the interrupt type notification table 2
An interrupt type 29h is obtained from 9a, and interrupt processing activation signals 29i to 29k are output in response thereto, and one of the interrupt processing routines (1) 29d to (n) 29f is activated. When the processing is completed, polling of the interrupt processing request notification table 29b is started again.

Next, the scheduling operation of the present embodiment will be described with reference to the flowchart of FIG. 11. First, the scheduling execution unit 13 checks whether or not there is an interrupt (ST111). Is performed. If there is an interrupt, the following processing is performed. Priority information storage unit 3 in which priorities between interrupt processing and periodic tasks are stored in advance
From 0, the priority information 32 of the interrupt process and the periodic task is obtained and compared (ST112). If the priority of the interrupt process is higher, the interrupt process is executed (ST114) and the interrupt is cleared (ST115).
If the priority of the interrupt processing is low, the interrupt is pending (ST113), and normal periodic scheduling in the first embodiment is performed. However, in this periodic scheduling, when there is no execution task (ST
124), a pending interrupt process is performed using this time slot (ST125 → ST126). After the interrupt processing, the interrupt is cleared (ST127). With the above operation, it is also possible to control the priority of the periodic scheduling and the non-periodic interrupt processing such as the error processing. That is, in the conventional example and the first embodiment,
Only the tasks specified by the user in advance and assigned to the timeslot management table 211 can be executed. However, by adding the interrupt generation unit 28 and the interrupt processing unit 29 as described above, error processing that occurs aperiodically can be performed. By setting the priority in advance, the periodic scheduling can be suspended and executed. In the present embodiment, an example in which the above-described interrupt processing function is added to that of the first embodiment of FIG. 1 has been described. However, the present embodiment can be applied to the conventional example of FIG.

Embodiment 3 FIG. FIG. 13 is a configuration diagram of a part related to scheduling of the computer system according to the third embodiment.
This embodiment is different from the S / W timer 1 in the first embodiment shown in FIG.
4. The time slot calculation section 16 and the time slot information storage section 18 are configured by hardware. That is, reference numeral 34 denotes a hardware (hereinafter abbreviated as H / W) timer which is a substitute for the S / W timer 14 in FIG. 1, and is originally provided in the computer system. An interrupt generator 35 generates an interrupt 37 to the scheduling execution unit 13 at each time slot time based on the clock 36 from the H / W timer 34, and 38 to 40 generate respective interrupts based on the clock 36 from the H / W timer 34. The interrupt generator 35 and the counters 38 to 40 are provided in place of the time slot calculation unit 16 in FIG. Bits 41 corresponding to the respective time slot values 1 to N are set by the outputs 42 of the counters 38 to 40, and the scheduling execution unit 13 sets the current time slot value 43 by the scheduling execution unit 13 every time an interrupt is generated from the interrupt generator 35. Is a time slot register to be read out, and is provided in place of the time slot information storage section 18 in FIG.

Next, the scheduling operation of this embodiment will be described with reference to the flowchart of FIG. Using the clock 36 of the H / W timer 34, the interrupt generator 35 generates an interrupt 37 to the scheduling execution unit 13 for each time slot time. The counter (1) 38 to the counter (N) 40 use the clock 36 of the H / W timer 34 to count the time slot values 1 to N, respectively, determined.
Set the corresponding bit of. Scheduling execution unit 1
3 receives the interrupt 37 for each time slot from the interrupt generator 35, goes to the time slot register 41, and obtains the time slot value 43 from the set bits (ST141). The scheduling execution unit 13
After acquiring the time slot value, the time slot register 41
Reset. Using this time slot value, the same scheduling processing as in the first embodiment is performed, and after waiting for an H / W timer interrupt (ST145), the process returns to the acquisition of the next time slot value, and the above operation is repeated. H for timer
By automatically setting the time slot value in the register using the / W timer, the load on the system can be reduced and the processing speed can be improved. That is, the first embodiment
In this example, the processing of acquiring the current time, the calculation of the time slot, and the notification of the time slot change interrupt to the scheduling execution unit 13 are all realized by software using the S / W timer function of the operating system. In this case, the previous value of the time slot needs to be held, and the overhead time (the system time in FIG. 7) increases. On the other hand, when the above functions are realized by hardware such as an interrupt generator, a counter, and a register using an H / W timer as in the present embodiment, it is not necessary to hold the previous value of the time slot. , Overhead can be reduced, and high-speed scheduling can be performed.

[0026]

As described above, according to the first aspect of the present invention, in a computer system having a function of managing and scheduling a plurality of tasks having a unique execution cycle and execution time, each An execution cycle determining means for determining an execution cycle; a classifying means for classifying each task from an execution level having a short execution cycle to a long execution level based on a result of the determination by the execution cycle determining means; Time slot allocating means for allocating the execution level to a time slot which is a time unit obtained by dividing a minimum reference period serving as a reference when checking by a predetermined value;
Comparing means for determining whether or not the execution cycle of the execution level in which the tasks of the minimum execution cycle are classified is shorter than the minimum reference cycle; and, based on the comparison result, according to a preset cycle.
A scheduling mode switching means for switching between a periodic scheduling mode for assigning the execution level to each time slot and a priority scheduling mode for assigning an execution level in which tasks having the minimum execution cycle are classified to all time slots; Scheduling execution means for executing task scheduling from the execution level assigned to the time slot corresponding to the time slot, wherein the execution cycle of the execution level in which the task of the minimum execution cycle is classified by the comparison means is shorter than the minimum reference cycle. When the determination is made, the scheduling mode switching means switches from the normal periodic scheduling mode to the priority scheduling mode, and based on this, the time slot allocating means sets the minimum execution cycle to all time slots. Tasks are assigned to categorized execution levels.Periodic scheduling is performed as much as possible to equalize the load on the processor, and if there is a task with a non-schedulable cycle, it is minimized. Since the execution is performed with priority, it is possible to obtain an effect that scheduling corresponding to tasks in all cycles can be performed.

According to the second aspect of the present invention, the execution cycle determining means for determining the execution cycle of each task, and each task is executed from a short execution level to a long execution level based on the determination result of the execution cycle determining means. Classifying means for classifying levels into levels, and time slot allocating means for allocating the execution level to a time slot which is a time unit obtained by dividing a minimum reference cycle, which is a reference when periodically checking task activation, by a predetermined value. Scheduling execution means for executing task scheduling from the execution level assigned to the time slot corresponding to the current time, and generating an interrupt to notify the scheduling execution means of the occurrence of an aperiodic event such as an error by interruption. Means, and interrupt processing means for performing processing when the interrupt occurs. When the interrupt occurs, when the interrupt processing has a higher priority than the periodic task based on the predetermined priority of the periodic task and the interrupt processing, the execution of the periodic task is temporarily suspended, and Since the interrupt processing means is made to execute the interrupt processing, periodic scheduling,
An effect is obtained in which priority control of interrupt processing that occurs aperiodically, such as error processing, can be performed.

On the other hand, according to the third invention, similarly to the first invention, the execution cycle determining means for determining the execution cycle of each task, and each task is executed based on the determination result of the execution cycle determining means. A classifying means for classifying the execution level from a short execution level to a long execution level; and a time slot which is a time unit obtained by dividing a minimum reference cycle, which is a reference for periodically checking task activation, by a predetermined value. A time slot allocating means for allocating a level, a comparing means for determining whether or not the execution cycle of the execution level in which the task of the minimum execution cycle is classified is shorter than the minimum reference cycle, and a predetermined setting based on the comparison result . According to the cycle,
A scheduling mode switching means for switching between a periodic scheduling mode for assigning the execution level to the time slot, a priority scheduling mode for assigning an execution level in which the tasks having the minimum execution cycle are classified to all the time slots, and a time corresponding to the current time. A scheduling execution means for executing task scheduling from an execution level assigned to a slot, and an interrupt generator for generating an interrupt to the scheduling execution means for each time slot time based on a clock from a hardware timer; A counter for counting each time slot value based on a clock from a timer; and a time slot value set by the counter. The scheduler is set every time an interrupt is generated from the interrupt generator. And a register for time slot value at the present time is read by the packaging executing means, when the execution cycle of the execution level minimum execution cycle of the task is classified by the comparison means it determines that less than a minimum reference period,
The scheduling mode switching means switches from a normal periodic scheduling mode to a priority scheduling mode, and based on this, the time slot allocating means allocates an execution level in which a task having a minimum execution cycle is classified to all time slots. Therefore, the same effects as those of the first invention can be obtained, and
By using the H / W timer as the timer and automatically setting the time slot value in the register, the load on the system can be reduced and the processing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a part related to scheduling of a computer system according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating an internal configuration of a scheduling mode selection unit in FIG. 1;

FIG. 3 is a flowchart showing operations of a scheduling mode selecting unit and a time slot allocating unit of FIG. 1;

FIG. 4 is a flowchart showing a continuation of FIG. 3;

FIG. 5 is a detailed diagram in a time slot corresponding task information table at the time of priority scheduling.

FIG. 6 is a flowchart showing an operation of a scheduling execution unit at the time of priority scheduling.

FIG. 7 illustrates an execution state of a task at the time of priority scheduling.

FIG. 8 is a configuration diagram of a part related to scheduling of a computer system according to a second embodiment of the present invention.

9 is an internal configuration diagram of the interrupt generation unit of FIG.

FIG. 10 is an internal configuration diagram of an interrupt processing unit in FIG. 8;

FIG. 11 is a flowchart showing the scheduling operation of FIG. 8;

FIG. 12 is a flowchart showing a continuation of FIG. 11;

FIG. 13 is a configuration diagram of a part related to scheduling of a computer system according to Embodiment 3 of the present invention.

FIG. 14 is a flowchart showing the scheduling operation of FIG.

FIG. 15 is a configuration diagram of a portion related to scheduling of a conventional computer system.

FIG. 16 is a diagram illustrating an execution state of a task at the time of scheduling.

FIG. 17 is a functional block diagram showing an internal configuration of a time slot assignment unit.

FIG. 18 is a detailed diagram in a time slot corresponding task information table.

FIG. 19 is a flowchart showing the operation of the time slot allocator in FIG. 15;

FIG. 20 is a flowchart showing a continuation of FIG. 19;

FIG. 21 is a flowchart showing the operation of the scheduling execution unit.

FIG. 22 is a diagram showing the order of checking the execution level.

[Explanation of symbols]

Reference Signs List 11 time slot allocating unit 11a execution period discriminating unit 11b classifying unit 11c time slot allocating unit 12 task information 13 scheduling executing unit (scheduling executing unit) 14 S / W timer 15 fixed period interrupt 16 time slot calculating unit 17 time slot change interrupt 18 Time slot information storage unit 19 Time slot value (changed value) 20 Time slot value (current value) 21 Time slot corresponding task information table 22 Table information (current value) 23 Table information (changed value) 24 Activation task queuing unit 25 Activation Requested task 26 Scheduling mode selection unit 26a Execution cycle determination unit 26b Classification unit 26c Comparison unit 26d Scheduling mode switching unit 27 Scheduling mode signal 28 Interrupt generation unit (Interrupt generating means) 29 Interrupt processing unit (interrupt processing means) 30 Priority information storage unit 31 Interrupt (including interrupt type) 32 Priority information 33 Interrupt processing request (including interrupt type) 34 H / W timer 35 Interrupt generator 36 Clock 37 Interrupt 38 to 40 Counter 41 Time slot register 42 Counter output 43 Time slot value 211 Time slot management table 212a to 212c Level management table 213a1 to 213an, 213b1, 213c1,
13c2 Task management table

Claims (3)

(57) [Claims] 1. A computer system having a function of managing and scheduling a plurality of tasks each having a unique execution cycle and execution time, an execution cycle determination means for determining an execution cycle of each task, and an execution cycle determination means Based on the determination result, a classifying means for classifying each task from an execution level having a short execution cycle to a long execution level, and a minimum reference cycle serving as a criterion for periodically checking task activation is divided by a predetermined value. Time slot allocating means for allocating the execution level to a time slot which is a unit of time; and comparing means for determining whether or not the execution cycle of the execution level in which the task of the minimum execution cycle is classified is shorter than the minimum reference cycle. Based on the result of this comparison, a preset
A scheduling mode switching means for switching between a periodic scheduling mode for assigning the execution level to each time slot according to a period, and a priority scheduling mode for assigning an execution level in which tasks of the minimum execution cycle are classified to all time slots; Scheduling execution means for executing task scheduling from the execution level assigned to the time slot corresponding to the time slot, wherein the execution cycle of the execution level in which the task of the minimum execution cycle is classified by the comparison means is shorter than the minimum reference cycle. When it is determined, the scheduling mode switching means switches from the normal periodic scheduling mode to the priority scheduling mode, and based on this, the time slot allocating means sets the minimum real time for all the time slots. Computer system and wherein the assigning the execution level period of the task is classified. 2. A computer system having a function of managing and scheduling a plurality of tasks each having a unique execution cycle and execution time, an execution cycle discrimination means for discriminating an execution cycle of each task, and an execution cycle discrimination means. Based on the determination result, a classifying means for classifying each task from an execution level having a short execution cycle to a long execution level, and a minimum reference cycle serving as a criterion for periodically checking task activation is divided by a predetermined value. Time slot allocating means for allocating the execution level to a time slot which is a unit of time; scheduling executing means for performing task scheduling from the execution level allocated to the time slot corresponding to the current time; An interrupt occurrence that notifies the above scheduling execution means of the occurrence of an event by an interrupt Means; and interrupt processing means for performing processing when the interrupt occurs. The scheduling execution means periodically performs the interrupt processing based on the predetermined periodic task and the priority of the interrupt processing when the interrupt occurs. A computer system wherein when the priority is higher than the task, the execution of the periodic task is temporarily interrupted and the interrupt processing means executes the interrupt processing. 3. A computer system having a function of managing and scheduling a plurality of tasks each having a unique execution cycle and execution time, an execution cycle determination means for determining an execution cycle of each task, and an execution cycle determination means. Based on the determination result, a classifying means for classifying each task from an execution level having a short execution cycle to a long execution level, and a minimum reference cycle serving as a criterion for periodically checking task activation is divided by a predetermined value. Time slot allocating means for allocating the execution level to a time slot which is a unit of time; and comparing means for determining whether or not the execution cycle of the execution level in which the task of the minimum execution cycle is classified is shorter than the minimum reference cycle. Based on the result of this comparison, a preset
Scheduling mode switching means for switching between a periodic scheduling mode for assigning each execution level to each time slot according to a period, and a priority scheduling mode for assigning an execution level in which tasks of the minimum execution cycle are classified to all time slots. Scheduling execution means for executing task scheduling from an execution level assigned to a time slot corresponding to time; an interrupt generator for generating an interrupt to the scheduling execution means for each time slot time based on a clock from a hardware timer; A counter that counts each time slot value based on a clock from a hardware timer; and a time slot value is set by the counter, and the schedule is set every time an interrupt is generated from the interrupt generator. A register from which the time slot value at the current time is read by the ring executing means, and when the comparing means determines that the execution cycle of the execution level at which the task of the minimum execution cycle is classified is shorter than the minimum reference cycle, The scheduling mode switching means switches from a normal periodic scheduling mode to a priority scheduling mode, and based on this, the time slot allocating means allocates an execution level in which a task having a minimum execution cycle is classified to all time slots. Computer system.