JP2000194573A - System and method for thread control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread control system which actively switches threads at intervals shorter than time slices of a computer system. SOLUTION: An execution priority setting part 202 has a function of resetting the execution priority of a specified thread in an executable state to a 1st value and a wait priority setting part 203 has a function of resetting the execution priority to a 2nd value lower than the 1st value. Then a schedule part 201 selects a thread to be executed next at each interval shorter than a time slice of the operating system 100, and resets the execution priority of the thread in an executed state to the 2nd value by using the wait priority setting part 230 and the execution priority of the selected thread to the 1st value by using the execution priority setting part 202, thereby making a thread management part 101 to switch the selected thread.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a thread control system operating under an operating system that can fixedly designate an execution priority given to a thread as a control unit when allocating a CPU, and to the thread control system. In particular, thread switching occurs at intervals shorter than the operating system time slice, and has its own execution priority that has more stages than the operating system can accept. The present invention relates to a thread control system and a thread control method that can be assigned to a thread.

[0002]

2. Description of the Related Art In recent years, the spread of computers has been remarkable, and various computer systems have been developed. In these computer systems, the CPU performs data processing by controlling the execution of a program, and the operating system performs thread management (scheduling) in order to control the execution of a plurality of data processing in a fair and appropriate order. ing.

A thread is a control unit when the operating system allocates a CPU to a program. The operating system determines a predetermined time called a time slice or the like based on the execution priority assigned to each thread. The thread to which the CPU is assigned is switched at each interval.

[0004]

By the way, thread switching by the operating system is performed when a thread in the execution state relinquishes the execution right, or
This is executed only when the time slice has expired, and if the thread that has released the event wait and the executing thread have the same execution priority, immediately switches to the thread that has released the event wait. Whether or not it depends on the design concept of each operating system.

[0005] Therefore, there is a problem that, in some cases, the thread that has been released from waiting for an event obtains the execution right, and in some cases, must wait for the next and subsequent schedulings, and the execution right may not be obtained for a long time. .

In addition, when the number of execution priority levels that can be accepted by the operating system is small, there is a problem that it is very difficult to implement an application program that must consider giving execution priority to threads. there were.

In consideration of these points, even under the existing operating system, by executing the unique thread switching control, the threads of the same priority can be impartially distributed at short intervals, and the threads whose event wait has been released can be released. It is desirable to be able to give execution rights preferentially, and also to be able to freely set the number of stages of execution priority without being restricted by the operating system.

The present invention has been made in view of such circumstances, and causes thread switching to occur at intervals shorter than the time slice of the computer system, and to increase the number of stages that can be accepted by the computer system. It is an object of the present invention to provide a thread control system capable of assigning a unique execution priority having a number of stages to a thread.

[0009]

In order to achieve the above-mentioned object, the present invention utilizes any two of the execution priorities managed by an operating system to execute a thread in an execution state. By resetting the degree to the lower of the two values, and resetting the execution priority of the next executable thread to be executed to the higher of the two values. , The thread switching by the operating system is actively generated.

According to the present invention, by resetting the execution priority at intervals shorter than the time slice of the operating system, finer thread control can be realized even under the existing operating system. Become.

Further, the execution priority managed by the operating system uses only two values, and the next thread to be executed is determined based on a unique priority independent of the execution priority managed by the operating system. By making the selection, it is possible to set the priority of each thread in a greater number of stages than the operating system can accept.

Further, in addition to the above two values, another value for the thread waiting for the event is used, and this value is set to a value having a higher priority than the above two values. When the thread whose event wait has been released and the thread being executed have the same execution priority, it is possible to immediately switch to the thread whose event wait has been released regardless of the design concept of the operating system.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a device configuration of the computer system according to the first embodiment.

As shown in FIG. 1, the computer system includes a CPU 1, a system memory 2, an external storage device 3, an input device 4, and an output device 5.

The CPU 1 executes and controls various programs including an operating system and utilities stored in the system memory 2.

The system memory 2 is a memory device serving as a main memory of the system, and stores various programs including an operating system and utilities executed and controlled by the CPU 1 and various data.

The external storage device 3 is, for example, a magnetic disk device or the like, and is a memory device serving as auxiliary storage of this system.

The input device 4 is, for example, a keyboard or a mouse, and controls input of a user interface.

The output device 5 is, for example, a display device or a printer, and controls the output of a user interface.

FIG. 2 is a diagram showing functional blocks relating to thread control of the computer system.

As shown in FIG. 2, the thread control of the computer system is performed by the operating system 10.
0 and the thread control system 200 operating under the operating system 100. These are configured as programs that are loaded from the external storage device 3 into the system memory 2 and that are executed and controlled by the CPU 1.

The operating system 100 controls the entire system, and includes a thread management unit 101 for controlling thread switching. When the thread in the execution state relinquishes the execution right or when the time slice expires, the thread management unit 101 selects a thread to be executed next based on the execution priority assigned to each thread. Then, thread switching is performed to allocate a CPU to the selected thread.

On the other hand, the thread control system 200 includes a thread management unit 101 of the operating system 100.
This is for actively generating the thread switching by the program, and includes a schedule unit 201, an execution priority setting unit 202, and a standby priority setting unit 203.

The schedule unit 201 calls the functions of the execution priority setting unit 202 and the standby priority setting unit 203, and determines the high / low relationship of the execution priority between the thread in the execution state and the thread in the executable state. By inverting the thread, the thread management unit 101 of the operating system 100 is instructed to switch threads.

The execution priority setting unit 202 resets the value of the execution priority of the thread in the executable state designated by the schedule unit 201 to a predetermined value. The value of the execution priority set by the execution priority setting unit 202 is
The priority has a higher value than the priority value set by the standby priority setting unit 203.

Then, the standby priority setting unit 203 resets the value of the execution priority of the thread in the execution state specified by the schedule unit 201 to a predetermined value.
The execution priority value set by the standby priority setting unit 203 has a lower priority than the priority value set by the execution priority setting unit 202.

That is, this computer system
It is characterized in that thread switching is appropriately controlled by using only two arbitrary values among the execution priorities managed by the operating system.

The operation principle of thread switching in this computer system will be described below with reference to FIG.

Here, the value of the execution priority set by the execution priority setting unit 202 is “24”, and the value of the execution priority set by the standby priority setting unit 20 is “22”.
And It is also assumed that there are two threads A and B in the initial state.

Now, it is assumed that [Thread A] is executing and [Thread B] is in a standby state. At this point, the execution priority value is [24] for [Thread A] and [Thread B]
Is "22". Then, the schedule unit 201
It is assumed that [Thread B] is selected as a thread to be executed next. At this time, the scheduling unit 201 resets the priority (system execution priority) of [Thread B] to “24” using the execution priority setting unit 202. As a result, [Thread B] becomes [Thread B '].

At this time, the schedule unit 201
Resets the priority (system standby priority) of [Thread A] to “22” using the standby priority setting unit 203. As a result, [Thread A] becomes [Thread A '].

Due to the operation of the execution priority by the schedule unit 201, the thread management unit 101 of the operating system 100 causes the high priority [thread B '].
Perform a thread switch to execute

As described above, by controlling the execution priority, thread switching can be actively generated without waiting for the end of the time slice, and finer thread control can be performed.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The device configuration of the computer system according to the second embodiment is the same as that of the first embodiment.

FIG. 4 is a diagram showing functional blocks relating to thread control of the computer system.

As shown in FIG. 4, the thread control of this computer system is controlled by the operating system 10.
0 and a schedule thread 300 and a schedule activation thread 310 operating under the operating system 100. These are loaded from the external storage device 3 into the system memory 2 and
It is configured as a program whose execution is controlled by U1, and the operating system 100 is the same as in the first embodiment.

On the other hand, the schedule thread 300 is provided by the thread management unit 101 of the operating system 100.
The schedule unit 301 includes an execution priority setting unit 302, a standby priority setting unit 303, and a timer waiting unit 30.
4 and the function of the event waiting unit 305 are called and executed.

The schedule unit 301, the execution priority setting unit 302, and the standby priority setting unit 303 are the same as the schedule unit 201, the execution priority setting unit 202, and the standby priority setting unit 203 described in the first embodiment. Each is applicable. That is, the schedule thread 300 is obtained by applying the thread control method described in the first embodiment. Then, the timer waiting unit 30
Reference numeral 4 denotes a unit for repeatedly activating the schedule unit 301 at intervals shorter than the slice time of the operating system 100, and the event wait unit 305 sets the schedule unit 30 when a predetermined event occurs.
1 is started.

The schedule activation thread 310
Has a schedule event generation unit 311,
Each time it is executed, the event waiting unit 305 generates an event that triggers the activation of the schedule unit 301 by using the schedule event generation unit 311.

Then, the schedule thread 300
Is given a higher execution priority than the value of the priority set by the execution priority setting unit 302, while the schedule activation thread 310 has the priority set by the execution priority setting unit 302. The execution priority of a value having a lower priority than the value of the degree and a higher priority than the value of the priority set by the standby priority setting unit 303 is assigned.

That is, this computer system
It is characterized in that thread switching is appropriately controlled by using only four arbitrary values among the execution priorities managed by the operating system.

The operation principle of thread switching in this computer system will be described below with reference to FIG.

Here, the value of the execution priority given to the schedule thread 300 is “25”, the value of the execution priority of the thread set by the execution priority setting unit 302 is “24”, and The value of the execution priority to be assigned is “23”, and the standby priority setting unit 30
The value of the thread execution priority set by 3 is “2”.
Therefore, as the initial state, the schedule thread 300 to which the priority value “25” is assigned, the schedule start thread 310 to which the priority value “23” is assigned, the schedule thread 300, and the schedule start thread 310 It is assumed that there are two threads A and B (for example, an application execution program) for which priority values are set.

Now, suppose that [Thread A] is executing and [Thread B] is in a standby state. At this point, the execution priority value is [24] for [Thread A] and [Thread B]
Is "22". There are two cases in which the execution right is transferred from [Thread A] to [Thread B]. (1) When the execution right is transferred by scheduling. (2) When the execution right is transferred because the thread in the execution state has entered the event waiting state.

First, the operation principle when the execution right is transferred by the scheduling of (1) will be described. In the following description, the expressions [] () will be described with reference to FIGS. 4 and 5.

When [Thread A] is in the execution state, the schedule unit 301 of the schedule thread 300
It is in a state of waiting for activation from one of the timer waiting unit 304 and the event waiting unit 305.

Here, when started from the timer waiting unit 304, the thread management unit 101 of the operating system 100 instructs the thread management unit 101 of the operating system 100 to execute the [schedule thread] (300) having the highest priority according to the instruction of the schedule unit 301. Switch. This means
This means that the schedule thread 300 is executed.

In the schedule thread 300, in the execution process, it is assumed that the schedule unit 301 selects, for example, [Thread B] in standby as the thread to be executed next. At this time, the schedule unit 301
In order to set the priority of the currently executing thread, the priority of [Thread B] is reset to “24” using the execution priority setting unit 302. As a result, [Thread B] becomes [Thread B '].

At this time, the schedule unit 301
Is the priority of the waiting / event waiting thread,
The priority of [Thread A] is reset to “22” using the standby priority setting unit 303. As a result, [Thread A]
Becomes [thread A '].

When these processes are completed, the [schedule thread] 300 relinquishes the execution right.

This [schedule thread] (300)
Has been abandoned, the thread management unit 101 of the operating system 100 executes thread switching to execute [Thread B '] having the highest priority at this time. Thus, [Thread B '] is executed.

Next, a description will be given of the operation principle in the case where the execution right is transferred because the thread in the execution state of (2) enters the event waiting state.

When [Thread A] is in the execution state, [Schedule Thread] having the highest priority (300)
Is in a state of waiting for activation from one of the timer waiting unit 304 and the event waiting unit 305. That is, the schedule thread 300 is not operating.

Here, assuming that [Thread A] has abandoned the execution right due to, for example, waiting for an event, the thread management unit 101 of the operating system 100
At that time, the thread is switched to execute the [schedule start thread] (310) having the highest execution priority. That is, the schedule activation thread 310
Will work.

In the schedule start thread 310, the schedule event generation unit 311 starts the event waiting unit 305 of the schedule thread 300, thereby generating an event that triggers the start of the schedule unit 301, and generates a schedule thread (schedule thread) ( 300) is started.

[Schedule thread] (300)
Because the priority is the highest, the operating system 10
The thread management unit 101 of “0” switches the thread from the currently running “schedule start thread” (310) to the “schedule thread” (300). That is, the schedule thread 300 operates.

In the execution process of the schedule thread 300, it is assumed that the schedule unit 301 selects, for example, the waiting [Thread B] as the next thread to be executed. At this time, the schedule unit 301
In order to set the priority of the currently executing thread, the priority of [Thread B] is reset to “24” using the execution priority setting unit 302. As a result, [Thread B] becomes [Thread B '].

At this time, the schedule unit 301
Is the priority of the waiting / event waiting thread,
The priority of [Thread A] is reset to “22” using the standby priority setting unit 303. As a result, [Thread A]
Becomes [thread A '].

When these processes are completed, the [schedule thread] 300 relinquishes the execution right.

This [schedule thread] (300)
Has been abandoned, the thread management unit 101 of the operating system 100 executes thread switching to execute [Thread B '] having the highest priority at this time. Thus, [Thread B '] is executed.

As described above, when it is detected that a thread in the regular or running state has entered the event waiting state, the execution priority is manipulated to actively switch the thread without waiting for the end of the time slice. And thread control can be performed more finely.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In the computer system according to the third embodiment, the thread control of the computer system according to the second embodiment is made to separately consider handling of a thread whose event wait has been released.

FIG. 6 is a diagram showing functional blocks relating to thread control of the computer system.

As shown in FIG. 6, the computer system has a schedule thread 300 according to the second embodiment.
Further, an event waiting priority setting unit 306 and an event waiting canceling processing unit 307 are added.

The event waiting priority setting unit 306 can reset the value of the execution priority of the thread specified by the schedule unit 301 to a predetermined value. The value of the execution priority set by the event waiting priority setting unit 306 is a value having a higher priority than the value of the priority assigned to the schedule thread 300 (highest priority).

Then, the event wait release time processing unit 307
Is a module that is called by a thread that has been released from the standby state and transitioned to the execution state, and has the priority of the thread that called itself and the thread that transitioned from the execution state to the executable state immediately before the thread that called itself. It is for re-setting properly.

That is, this computer system
It is characterized in that thread switching is appropriately controlled by using only five arbitrary values of the execution priority managed by the operating system.

Hereinafter, the operation principle of thread control in this computer system will be described with reference to FIG.

Here, the event wait priority setting unit 30
The event waiting priority set by 6 is “26”,
The value of the execution priority assigned to the schedule thread 300 is “25”, the value of the execution priority set by the execution priority setting unit 302 is “24”, and the value of the execution priority assigned to the schedule activation thread 310 Is “23”, and the value of the execution priority set by the standby priority setting unit 303 is “22”. As the initial state, as in the second embodiment, the schedule thread 300, the schedule start thread 310, and the threads A and B
Assume that there are threads.

Now, it is assumed that [Thread A] is in execution and [Thread B] is in a standby state. At this point, the execution priority value is set to "24" for [Thread A] by the execution priority setting unit 302, and to "22" for [Thread B] by the standby priority setting unit 303.

The operation of the thread control in this computer system is different from that of the second embodiment described above in the operation when the currently executing thread is in the event waiting state. Therefore, the operation principle in this case will be described below.

When [Thread A] is in the execution state,
The [schedule thread] (300) is in a state of waiting for activation from one of the timer waiting unit 304 and the event waiting unit 305. That is, the schedule thread 300 is not operating.

Here, when [Thread A] relinquishes the execution right due to waiting for an event, the thread management unit 101 of the operating system 100 executes the [Schedule Start Thread] (310) having the highest priority at that time. Perform thread switching to achieve this. That is, the schedule activation thread 310 operates.

In the schedule start thread 310, the schedule event generating means 311 starts the event waiting unit 305 of the schedule thread 300, thereby generating an event that triggers the start of the schedule unit 301, and generates a schedule thread (300) ).

[Schedule thread] (300)
Since the priority is higher than the [schedule start thread] (310), the thread management unit 101 of the operating system 100 changes the running [schedule start thread] (310) to the [schedule thread] (30).
Perform a thread switch to 0). That is, the schedule thread 300 operates.

In the schedule thread 300, it is assumed that the schedule unit 301 has selected [thread B] as the next thread to be executed. At this time, the scheduling unit 301 resets the priority of [Thread B] to “24” using the execution priority setting unit 302. as a result,
[Thread B] becomes [Thread B '].

At this time, the schedule unit 301
Sets [Thread A] in the event wait release processing unit 307 so that the event wait release processing unit 307 is called after the event wait is released, and sets the [Thread A] using the event wait priority setting unit 306 [ The priority of the thread A] is reset to “26”. As a result, [Thread A] becomes [Thread A '].

When these processes are completed, the [schedule thread] 300 relinquishes the execution right.

This [schedule thread] (300)
Has been abandoned, the thread management unit 101 of the operating system 100 switches threads to execute [Thread B '] having the highest priority at this time. Thereby, [Thread B ']
Is executed.

Thereafter, if an event that [Thread A '] has been waiting for occurs during the execution of [Thread B'], the event waiting cancellation processing unit 307 of the schedule thread 300 is called. Then, the event-wait-release processing unit 307 compares the priorities of [Thread A '] and [Thread B'] of the thread management unit 101. If the priority of the thread A is high, for example, the [Thread B] '] To [Thread A'], the priority of [Thread A '] is reset to "24". As a result, [thread A '] becomes [thread A "].

Further, the event wait release time processing unit 307
Resets the priority of [thread B '] to "22". As a result, [Thread B '] becomes [Thread B "] and enters the standby state again.

At this point, the thread having the highest priority at this point is [Thread A ″]. Therefore, the thread is switched by the thread management unit 101 of the operating system 100 and [Thread A] after the waiting is released. The processing of the thread A ″] is continued.

On the other hand, when comparing the priorities of [Thread A '] and [Thread B'], when the priority of [Thread B '] is high, the event waiting release processing unit 30
7 resets the priority of [Thread A '] to "22". In this embodiment, since the currently executing thread remains [Thread B '], [Thread B'] is continuously executed.

As described above, in comparison with the thread control performed by the computer system according to the second embodiment, more detailed thread switching control can be performed when it is detected that the event wait has been released.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. The computer system according to the fourth embodiment applies the above-described thread control method of the present invention to give a thread a unique execution priority having a greater number of stages than the operating system can accept. Is made possible.

FIG. 8 shows an example of a priority managed by the operating system (system priority) and a unique priority independent of the priority managed by the operating system (unique priority). Here, it is assumed that the operating system has 16 levels of priority, of which the lower 8 levels are variable priorities and the upper 8 levels are fixed priorities. Therefore, normally, the thread can use only the priority of 8 to 15. Thus, in this computer system, by providing a unique priority, the number of threads is reduced to eight.
To 255 can be used. This allows the application program to perform more detailed operation control.

FIG. 9 is a diagram showing functional blocks related to giving execution priorities of the computer system.

As shown in FIG. 9, the assignment of the execution priority in this computer system is controlled by a thread control system 400. It is assumed that the thread control system 400 includes, as the schedule unit 401, a mechanism for practicing the thread control method described in the first to third embodiments. The thread control system 400 further includes a priority information holding unit 402 and a priority management unit 403.

The operation of giving the execution priority in the thread control system 400 is roughly classified into the following two operations. (1) When a Thread Sets Unique Priority (2) When a Thread Acquires Unique Priority First, the operation principle when the thread of (1) sets a unique priority will be described.

The application program sets the priority of the thread to be generated to the unique priority of 8 to
The thread control system 400 makes a request by designating an arbitrary value from among the 255 values.
The received priority is stored in the priority information holding unit 402.

Thereafter, the unique priority held in the priority information holding unit 403 is used as basic information for the schedule unit 401 to select a thread to be executed next.

Next, the principle of operation when the thread (2) acquires the unique priority will be described.

The application program requests the thread control system 400 to acquire the priority of the thread to be generated. In the thread control system 400, the request is accepted by the priority management unit 403, and the priority is set to 8 to An appropriate value in 255 is assigned and returned to the thread, and the assigned unique priority is stored in the priority information holding unit 402.

Thereafter, the unique priority held in the priority information holding unit 403 is used as basic information for the scheduling unit 401 to select a thread to be executed next.

Therefore, when this computer system applies, for example, the thread control method described in the second embodiment, only four of the priority values managed by the operating system are used. It is possible to provide the user with a value of 8 to 255 as a unique priority only by using four of the eight values prepared as the fixed priority of the degree.

As described above, it is possible to provide a thread with a higher number of priorities than the number of stages that can be accepted by the operating system, and the application program can perform finer thread control based on this unique priority. It becomes possible.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. The computer system according to the fifth embodiment enables the computer system according to the fourth embodiment to control the assignment of a priority to a thread generated by an application program that does not support the use of a unique priority. .

FIG. 10 shows an example of correspondence between the priority managed by the operating system (system priority) and a unique priority independent of the priority that can be accepted by the operating system (unique priority). According to this correspondence table, when an application program that does not support the use of the unique priority requests the setting of the priority for the thread to be created by designating the system priority 12, for example, It is understood that it is sufficient to control the thread switching.

FIG. 11 is a diagram showing functional blocks related to giving execution priorities of the computer system.

As shown in FIG. 11, this computer system has a thread control system 400 according to the fourth embodiment.
And a priority conversion unit 404 and a priority correspondence table 405.

The operation of giving an execution priority in the thread control system 400 and different from the operation of the thread control system 400 of the fourth embodiment is roughly classified into the following two operations.
One. (1) When the thread sets the system priority (2) When the thread acquires the system priority First, the operation principle when the thread of (1) sets the system priority will be described.

The application program requests the setting of the priority of the thread to be created by specifying an arbitrary value from 8 to 15 which is the system priority. The thread control system 400 converts this request into a priority conversion. Part 4
04, and is converted to a unique priority based on the priority correspondence table 405 having contents as shown in FIG. Then, the priority conversion unit 404 transfers the converted unique priority to the priority management unit 403, and the priority management unit 403 stores the transferred unique priority in the priority information holding unit 402. I do.

Thereafter, the unique priority held in the priority information holding unit 403 is used as basic information for the schedule unit 401 to select a thread to be executed next.

Next, the operation principle when the thread (2) acquires the system priority will be described.

The application program requests the thread control system 400 to acquire the priority of the thread to be generated. In the thread control system 400, the request is accepted by the priority conversion unit 403, and the original priority of 8 to 255, and assigns an appropriate value among the values associated with the system priority on the priority correspondence table 405, and assigns the system priority corresponding to the assigned unique priority to the thread. And returns the assigned unique priority to the priority management unit 403. Then, the unique priority is stored in the priority information holding unit 402 by the priority management unit 403.

Thereafter, the unique priority held in the priority information holding unit 403 is used as basic information for the schedule unit 401 to select a thread to be executed next.

Therefore, the system priority managed by the operating system and the unique priority can be mutually converted, and the thread generated by the application program corresponding to the use of the unique priority and the use of the unique priority are not supported. Even if a thread generated by an application program is mixed, it is possible to control the assignment of an appropriate priority.

[0109]

As described above in detail, according to the present invention, the execution priority is reset at intervals shorter than the time slice of the operating system, so that even under the existing operating system, finer details can be obtained. Thread control can be realized.

Further, by selecting a thread to be executed next based on a unique priority independent of the execution priority managed by the operating system, the number of stages larger than the number of stages that can be accepted by the operating system is selected. To set the priority of each thread.

Further, by assigning a higher priority to the thread waiting for the event than the thread in the execution state, the thread that has released the event and the thread that is executing have the same execution priority. In this case, it is possible to immediately switch to the thread whose event wait has been released, regardless of the design concept of the operating system.

[Brief description of the drawings]

FIG. 1 is an exemplary view showing a device configuration of a computer system according to a first embodiment of the present invention.

FIG. 2 is an exemplary view showing functional blocks relating to thread control of the computer system according to the first embodiment;

FIG. 3 is an exemplary view for explaining the operation principle of thread control in the computer system according to the first embodiment;

FIG. 4 is an exemplary view showing functional blocks relating to thread control of the computer system according to the second embodiment;

FIG. 5 is an exemplary view for explaining the operation principle of thread control in the computer system of the second embodiment.

FIG. 6 is an exemplary view showing functional blocks relating to thread control of the computer system according to the third embodiment;

FIG. 7 is an exemplary view for explaining the operation principle of thread control in the computer system of the third embodiment.

FIG. 8 is a diagram illustrating an example of a priority (system priority) managed by an operating system and a unique priority (unique priority) independent of the priority managed by the operating system in the fourth embodiment. .

FIG. 9 is an exemplary view showing functional blocks relating to the assignment of an execution priority of the computer system according to the fourth embodiment;

FIG. 10 shows an example of correspondence between the priority managed by the operating system of the fifth embodiment (system priority) and a unique priority independent of the priority managed by the operating system (unique priority). FIG.

FIG. 11 is an exemplary functional block diagram of the computer system according to the fifth embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU 2 ... System memory 3 ... External storage device 4 ... Input device 5 ... Output device 100 ... Operating system 101 ... Thread management unit 200, 400 ... Thread control system 201, 301, 401 ... Schedule unit 202, 302 ... Execution priority Degree setting units 203, 303 ... Waiting priority setting unit 304 ... Timer waiting unit 305 ... Event waiting unit 306 ... Event waiting priority setting unit 307 ... Event waiting cancellation processing unit 310 ... Schedule start thread 311 ... Schedule event generating unit 402 Priority information holding unit 403 Priority management unit 404 Priority conversion unit 405 Priority correspondence table

Claims (9)

[Claims] 1. A thread control system operating under an operating system capable of fixedly specifying an execution priority given to a thread as a control unit when allocating a CPU, wherein the execution priority of a thread in an execution state is provided. First setting means for resetting the degree to the first value, and second setting for resetting the execution priority of the thread in the executable state to a second value higher in priority than the first value. Setting means, selecting a thread to be executed next from all threads, resetting the execution priority of the selected thread to the second value using the second setting means,
Scheduling means for causing the operating system to execute switching to the selected thread by resetting the execution priority of the thread in the execution state to the first value using the first setting means. A thread control system. 2. The thread which operates under an operating system in which an execution priority given to a thread as a control unit when allocating a CPU can be fixedly designated, and which is given a first value of execution priority. And a schedule start thread for starting the schedule thread to be given a second value execution priority lower in priority than the first value. The system, wherein the schedule thread sets an execution priority of a thread in an executable state or a standby state to a third value having a lower priority than the first value and a higher priority than the second value. First setting means for resetting the execution priority of the thread in the execution state to a fourth value lower in priority than the second value A second setting unit, and a thread to be executed next is selected from all the threads in an executable state, and the execution priority of the selected thread is set to the third thread by using the first setting unit. By resetting the execution priority of the thread in the execution state to the fourth value by using the second setting means, the operating system switches the execution thread to the selected thread. A thread control system comprising: a scheduler for executing the thread control. 3. The thread which operates under an operating system in which an execution priority given to a thread as a control unit when allocating a CPU can be fixedly designated, and to which a first value of execution priority is given And a schedule start thread for starting the schedule thread to be given a second value execution priority lower in priority than the first value. A scheduler, wherein the schedule thread resets an execution priority of an event waiting thread in an execution state to a third value having a higher priority than the first value, and an executable state. Alternatively, the execution priority of the thread in the waiting state is set to a fourth value having a lower priority than the first value and a higher priority than the second value. Second setting means for resetting; third setting means for resetting the execution priority of the thread in the execution state to a fifth value lower in priority than the second value; A fourth setting unit that is set so as to be called in advance when the thread is released, and resets the execution priority of the thread set to the third priority value to the fourth value or the fifth value When there is a thread that has transitioned from the execution state to the standby state, the execution priority of this thread is reset to the third value using the first setting means, and the next thread to be executed is executed. A thread selected from all threads in the enabled state, the execution priority of the selected thread is set to the fourth value using the second setting means, and the thread set to the third value is set. Was released from standby and returned to running Based on the priority of said third and set thread value the fourth set thread value,
The execution priority is set to the fourth setting value using the fourth setting means.
Alternatively, when the thread of the third value is set to the fourth value, the fourth value is set to the fourth value.
By resetting the execution priority of the thread set to the value of to the fifth value using the fourth setting means,
Scheduling means for causing the operating system to execute switching to the selected thread. 4. The schedule thread, wherein the schedule thread comprises: timer activation means for repeatedly activating the schedule means at a predetermined interval shorter than a time slice of the operating; and a schedule activation thread for notifying that a predetermined event has occurred. 4. The thread control system according to claim 2, further comprising an event activating means for activating said scheduling means in response to the determination made by the thread control means. 5. An independent priority management unit for assigning a unique priority to each thread independently of an execution priority managed by the operating system, wherein the scheduling unit performs the unique priority management. 5. The thread control system according to claim 1, wherein a thread to be executed next is selected based on a unique priority managed by the means. 6. A priority conversion means for maintaining a correspondence between an execution priority managed by the operating system and the unique priority, and converting an execution priority managed by the operating system into the unique priority. The thread control system according to claim 5, further comprising: 7. A thread control method applied to a thread control system operating under an operating system capable of fixedly specifying an execution priority given to a thread as a control unit when allocating a CPU, comprising: The thread to be executed is selected from among all the threads, the execution priority of the selected thread is reset to the first value, and the execution priority of the thread in the execution state is changed from the first value. A thread control method for causing the operating system to execute switching to the selected thread by resetting the operating system to a second value having a lower priority. 8. The thread which operates under an operating system in which an execution priority given to a thread as a control unit when allocating a CPU can be fixedly designated, and to which an execution priority of a first value is given. A schedule thread for causing the switching of the schedule thread, a schedule start thread for starting the schedule thread to which a second value of execution priority lower than the first value is given, and an executable state Or first setting means for resetting the execution priority of the thread in the standby state to a third value lower in priority than the first value and higher in priority than the second value; and And a second setting means for resetting the execution priority of the thread in the second step to a fourth value lower in priority than the second value. A thread to be executed next is selected from all threads in an executable state, and the execution priority of the selected thread is set to the third value by using the first setting means. And the operating system switches to the selected thread by resetting the execution priority of the thread in the execution state to the fourth value using the second setting means. A thread control method. 9. The thread which operates under an operating system in which an execution priority given to a thread as a control unit when allocating a CPU can be fixedly designated, and to which an execution priority of a first value is given A schedule thread for causing the switching of the schedule thread, a schedule start thread for starting the schedule thread to which a second value of the execution priority lower than the first value is given, and First setting means for resetting the execution priority of the event waiting thread to a third value higher in priority than the first value; and setting the execution priority of the thread in the executable state or the standby state to the third value. A second setting unit for resetting the priority to a fourth value having a lower priority than the value of 1 and a higher priority to the second value; and setting the execution priority of the thread in the execution state to the fourth value. A third setting means for resetting to a fifth value lower in priority than the second value, and a third priority value set to be called in advance when the event wait is released And a fourth setting means for resetting the execution priority of the thread set to the fourth value or the fifth value to a thread control system, the method comprising: When there is a thread that has transitioned to the state, the execution priority of this thread is reset to the third value using the first setting means, and all the threads to be executed next are set to the executable state. A thread is selected from the threads, and the execution priority of the selected thread is set to the fourth value by using the second setting means, and the thread set to the third value is released from the standby state. Return to the running state Based on the priority of the thread set to the third value and the thread set to the fourth value,
The execution priority is set to the fourth setting value using the fourth setting means.
Alternatively, when the thread having the third value is set to the fourth value, the execution priority of the thread set to the fourth value is changed to the fifth value. 4
And causing the operating system to execute switching to the selected thread by resetting the thread to the fifth value using the setting means.