JP2003256067A - Power saving control system, power saving control method, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power saving control system for deciding operation clock of a processor by considering the number of tasks in waiting states in addition to priorities of tasks. <P>SOLUTION: The power saving control system has a priority table for keeping a plurality of priorities and the number of tasks which are waiting for execution according to the respective priority, a CPU clock table 105 for keeping a plurality of operation clock values capable of setting to the processor, a clock boundary value table 106 for keeping a reference value for deciding the operation clock of the processor and a clock decision part 107 for selecting the operation clock from the CPU clock table 105 by calculating loading value of the processor with the plurality of priorities and the number of tasks and by using the calculated loading value and the reference value and for setting the selected operation clock to the processor. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving control system for a processor having dynamic clock control. In particular, the present invention relates to a method for selecting an appropriate CPU clock according to the operating status of a task in an operating system that controls the execution of tasks based on priority.

[0002]

2. Description of the Related Art As a method for determining the operating clock of a processor whose operating clock can be dynamically changed, Japanese Patent Laid-Open Nos. 9-297688 and 10-14
3274. These determine the operation clock based on the execution time required for the task to perform processing. Further, in Japanese Patent Laid-Open No. 9-297688, it is also established that a task having the highest operation clock obtained from the execution time required for processing is given a high priority.

[0003]

However, in these methods, in a real-time system in which there is a time constraint from the start to the end of processing, it may be inconvenient to calculate the operating clock from the execution time required for processing. . For example, even if a task with a high priority is set, if the required execution time is short, a low operation clock will be calculated and executed with a low operation clock, and as a result, processing cannot be completed within the time constraint. was there. Further, as a task that constitutes a general real-time system, a task having a higher priority tends to require a shorter processing time, and there is a problem in that it is necessary to select an operation clock in consideration of this point. It was

An object of the present invention is to provide a control method and a control method for realizing power saving while taking into consideration the constraint of task execution time in a real-time system.

[0005]

A power saving control system according to the present invention is a power saving control system for controlling an operation clock of a processor for operating a plurality of tasks, wherein a plurality of priorities and the plurality of priorities are respectively set. Priority table that holds the number of tasks waiting for execution, a clock table that holds a plurality of operating clock values that can be set in the processor, and And the number of tasks and a plurality of read priority, the load value applied to the processor is calculated, using the calculated load value,
And a clock determining unit that selects an operation clock value from the clock table and sets the selected operation clock value in the processor.

The power saving control system further includes a reference value table holding a reference value for determining the operation clock of the processor, and the clock determination unit reads out the reference value from the reference value table and performs the reference. The operation clock is selected using the value and the load value.

The priority table further holds a weighting value corresponding to each of the plurality of priorities, and the clock determining unit uses the plurality of priorities, the number of tasks, and the weighting value. The load value is calculated.

The priority table further holds set clock values corresponding to each of the plurality of priorities,
The clock determination unit, when calculating the load value,
It is characterized in that the set clock value is used.

The power saving control system further inputs either the task name of which execution is requested or the task name of which execution has been completed, acquires the priority from the input task name, and uses the acquired priority. And a task management unit for updating the number of tasks held in the priority table.

The power saving control method is characterized in that the clock determination unit is activated when the task management unit updates the number of tasks held in the priority table.

The power saving control method is characterized in that the clock determining unit is activated at a predetermined cycle.

A power-saving control method according to the present invention is a power-saving control method for controlling an operation clock of a processor for operating a plurality of tasks, the method including a plurality of priorities and a priority corresponding to each of the plurality of priorities. A priority table storing step of storing the number of tasks waiting to be executed in the priority table, a clock table storing step of storing a plurality of operation clock values that can be set in the processor in the clock table, and the priority table From the plurality of priorities and the number of the task is read from, using the plurality of read priority and the number of tasks, to calculate the load value applied to the processor, using the calculated load value,
A clock determining step of selecting an operation clock value from the clock table and setting the selected operation clock value in the processor.

A program for causing a computer to execute power saving control according to the present invention is a program for causing a computer to execute power saving control for controlling an operation clock of a processor for operating a plurality of tasks. The priority table storing process for storing the number of tasks waiting for execution according to the respective priorities in the priority table and the plurality of operation clock values that can be set in the processor are stored in the clock table. A clock table storage process, the plurality of priorities and the number of tasks are read from the priority table, the load value applied to the processor is calculated using the plurality of read priorities and the number of tasks, Using the calculated load value, select the operating clock value from the above clock table and select the operating clock. The click value; and a clock determination process for setting to said processor.

A computer-readable recording medium in which a computer program for executing the power saving control according to the present invention is recorded is a program for executing the power saving control for controlling the operation clock of a processor for operating a plurality of tasks by the computer. In a recording medium in which is recorded, a priority table storing process for storing a plurality of priorities and the number of tasks waiting to be executed according to the priorities corresponding to the plurality of priorities in a priority table, and setting to the processor. A clock table storing process of storing a plurality of operation clock values that can be performed in a clock table, and reading the plurality of priorities and the number of tasks from the priority table, and reading the plurality of priorities and the number of tasks With and
A clock determining process for calculating a load value applied to the processor, selecting an operation clock value from the clock table using the calculated load value, and setting the selected operation clock value to the processor. To do.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As a task constituting a general real-time system, it is necessary to select an operation clock in consideration of the fact that a task having a higher priority tends to require a shorter processing time. According to the present invention, by retaining the information that influences the CPU operation clock according to the priority level for each priority, it becomes possible to select a higher CPU operation clock as the number of high-priority tasks existing increases. Provided are a power saving control method and method for realizing power saving of a processor by selecting a minimum operation clock while retaining a time constraint in a real-time system. Hereinafter, an example of the embodiment will be described.

Embodiment 1. FIG. 1 is an example of a block diagram showing the function of the power saving control system of the present invention. In FIG. 1, 101 is the entire operating system in which the present invention is actually installed. Operating system 1
01 has the minimum required functions for implementing the present invention and includes the following components.

Reference numeral 102 denotes a task management unit that manages and controls information / state of a task that is an execution subject managed by the operating system. The task management unit 102 has a function 103 for operating a ready queue that manages tasks waiting for execution by the CPU in the form of a list and a ready queue. 104 is a CPU (C
internal Processing Unit) It is executed based on an interrupt from an external timer hardware, and realizes various time-related functions (for example, timeout and periodic operation) related to the time and task in the operating system 101. It is a time management department.

Reference numeral 105 is a CPU clock table (clock table) showing a list of operation clocks that can be taken by the CPU. 106 is the CPU clock table 10
5 is a clock boundary value table showing reference values for selecting each operation clock of No. 5; The “clock boundary value table” is also called a “boundary value table” or a “reference value table”. Reference numeral 107 quantifies the current CPU load based on the information held in the ready queue in the task management unit 102, selects a CPU operation clock suitable for the CPU load from the clock boundary value table 106, and actually selects the CPU load. A CPU clock determination unit that accesses the CPU clock control hardware 108 to change the operation clock.

FIG. 2 shows the priority table 201, the ready queue 202, and the boundary value table 2 according to the first embodiment.
04 is a diagram illustrating a content example of a CPU clock table 203. In FIG. 2, like the general real-time OS, the ready queue constitutes a list for each priority, and the priority table 201 that manages the entire list as an array has tasks linked to the list. Priority indicating the priority of, and Po indicating the first task in the list
The list stores inter_ and list_no indicating the number of tasks connected to the ready queue list. In a general real-time OS, the priority table 2
01 does not normally have a prio area and is managed by a subscript of the array, but here, for convenience of explanation, it is assumed that the priority table 201 has information. In 201, the smaller the numerical value of the priority, the higher the priority of the process. In other words, prio = 1 has the highest priority and p
rio = 4 is the lowest priority task.

Reference numeral 202 is a Point of the priority table 201.
It is a ready queue list (also referred to as a ready queue) whose head is indicated by ter, and all tasks in the execution waiting state are connected to one of the ready queues 202. The ready queue 202 is generally a FIFO (Firs).
t In First Out). That is, the task added later is connected to the end of the list, and the CPU is assigned from the task at the top of the list.

Reference numeral 203 denotes a CPU clock table that holds a list of operation clocks that can be taken by the CPU, and indicates that 30, 40, 50 and 60 clocks can be dynamically set in this embodiment. In a typical CPU, the unit of these numerical values is megahertz. Reference numeral 204 denotes a clock boundary value table 204, which indicates a threshold value between the operation clocks in four stages shown by 203 as a CPU load value. For example, the clock boundary value table 20
The numerical value 5 in 4 is a numerical value for determining whether the CPU clock is 30 or 40, and the CPU load value is 0.
If ~ 4, the clock is 30, and if 5 or more, the clock is 4
It indicates that it is set to 0. Further, the other numerical values 10 and 15 of the clock boundary value table 204 have the same meaning.

FIG. 3 is a flow chart showing the processing of the CPU clock determining unit in the first embodiment. In FIG. 3, “prio_max” indicates the maximum numerical value of the priority managed by the priority table 201, and in the table configuration of FIG. 2, prio_max = 4. Also, pr
io ⁱ and list_no ⁱ represent the values of prio and list_no in the element of the index i as the array of the priority table 201 in the priority table,
In the table configuration of FIG. 2, 201a if i = 0
, Prio ⁱ = 1, list_no ⁱ = 1 and i =
If 2, it indicates 201c, and prio ⁱ = 3, list_
no ⁱ = 2.

Next, the processing of the CPU clock determining unit 107 in the first embodiment will be described with reference to FIGS.
The CPU clock determination unit 107 uses the index i, CP
The total sum of U load values, Total, is used as a variable. Step 301 is initialization of internal data in the CPU clock determination unit 107. Initialization of the index i, the total sum of CPU load values, Total, and other necessary initialization are performed. Next, in step 302, the range of the index i is checked, and if it is within the range, the priority table 201
It can be seen that the index i is valid in. As a result, if it is within the range, in step 303, the CPU in the element of the priority table 201 of the index i
The load value is calculated as a value obtained by multiplying the number of tasks connected to the ready queue 202 by the priority value, and is added to Total indicating the sum of the CPU load values in all ready queues 202. Then, in step 304, set the index to 1
And proceeds to step 302. Steps 302-3
By repeating 04, all ready queues 202
The sum of the CPU load values for is entered in Total, and the process proceeds to step 305.

In the table structure of FIG. 2, the CPU load value added to Total in step 303 is 2
01a = 4, 201b = 0, 201c = 4, 20
It becomes 1 in 1d, and when it proceeds to step 305,
Total = 9. Next, in step 305, the above-mentioned Total value and clock boundary value table 204
And the clock value for operating the CPU is fetched from the CPU clock table 203 and put in clock in step 306. In step 307, the obtained clock is set to the CPU clock control hardware 1
Set to 08 to change the operating clock of the CPU
The processing of the clock determination unit 107 is ended.

The comparison with the clock boundary value table 204 in steps 305 and 306 and the extraction of the clock value from the CPU clock table 203 are performed by the above-mentioned To.
It may be added in the loop process 302 to 304 for obtaining tal, and the same result is obtained.

Further, the reference value held in the boundary value table can be changed depending on the operating condition of the computer. It is desirable to have an interface for the user to change the standard value.

With the above processing, the more tasks in the ready queue 202 having higher priority can be operated with a higher CPU clock, and generally, in a real-time system in which a task with a higher priority has a severe processing time constraint, An appropriate CPU operating clock can be obtained.
If a task with a relatively low priority runs,
Since it can be operated with a low-speed clock that consumes less power, it is possible to appropriately adjust the importance and urgency of processing and power saving.

As described above, the power saving control system of this embodiment is provided with the following components and the table for storing data, and selects the optimum processor operating clock in consideration of the task priority. It is characterized by (A) A priority table in which the number of tasks having the same priority in the ready queue is added. (B) A CPU clock table that holds the values of the operation clocks that the processor can take. (C) A boundary value table holding a reference value for determining each operation clock of the processor. (D) The current load value of the processor is calculated from the priority value of the priority table and the number of tasks of the same priority, and the optimum CPU operating clock for the current processor load is set by comparison with the boundary value table. , CPU clock determination unit.

Embodiment 2. Next, the second embodiment will be described. The configuration of the power saving control system of this embodiment is the same as the block diagram shown in FIG. FIG. 4 is a diagram showing an example of contents of the priority table 401, the ready queue 202, the boundary value table 204, and the CPU clock table 203 in the second embodiment. In FIG. 4, 2
02 to 204 are the same as those in FIG. 401 is shown in FIG.
Although the same priority table as that of No. 201, a weighting value W when the CPU load value is calculated for each priority is stored as its constituent element.

FIG. 5 is a flow chart showing the processing of the CPU clock determining unit in the second embodiment. In FIG. 5, prio_max, prio ⁱ , and list_no ⁱ
Has the same meaning as described in FIG.

Next, the processing of the CPU clock determining unit 107 in the second embodiment will be described with reference to FIGS. 4 and 5. Steps 301 to 302 and steps 304 to 307 in FIG. 5 are the same as those in the first embodiment. The description is omitted because it is the same as the one described above. In step 503, the CPU load value for each ready queue 202 is calculated and added to Total, but the calculation of the CPU load value for each ready queue 202 is multiplied by the weight W set for each priority. Here, W ⁱ is the value of W in the priority table 401 indicated by the index i, and if i = 0, 401
It shows W which is W of a and 10 which is W of 401d when i = 3. As a result of the loop processing of steps 302, 503 and 304, in the table configuration in FIG. 4, the total CPU load value Total becomes 15, and according to the clock boundary value table 204 and the CPU clock table 203,
60 is set in the clock in step 306.

The comparison with the clock boundary value table 204 and the extraction of the clock value from the CPU clock table in steps 305 and 306 are performed by the above-mentioned Total.
May be added in the loop process 302, 503, 304 to obtain the same result.

The weighting value W held in the priority table can be changed depending on the operating status of the computer. It is desirable that an interface is prepared for the user to change the weight value W.

With the above-described processing, as the ready queue has more tasks with higher priority, the task can be operated with a higher CPU clock and the CPU load value can be weighted for each priority. According to the actual situation of the
Appropriate adjustment of processing importance / urgency and power saving can be made.

As described above, in this embodiment, in addition to the power saving control method of the first embodiment, the priority table has
The load is assigned to each priority, and the weight for each priority is included in the load value calculation of the processor.

Embodiment 3. Next, a third embodiment will be described. The configuration of the power saving control system of this embodiment is the same as the block diagram shown in FIG. FIG. 6 is a diagram showing an example of contents of the priority table 601, the ready queue 202, and the CPU clock table 203 in the third embodiment. Note that the boundary value table is not necessary in this embodiment. In FIG. 6, 202 to 203 are
It is the same as FIG. Reference numeral 601 is a priority table similar to 201 in FIG. 2, but as its constituent elements, a CPU clock value Limit to be operated for each priority is stored.

FIG. 7 is a flowchart showing the processing of the CPU clock determining unit in the third embodiment. In FIG. 7, prio_max and list_no ⁱ have the same meanings as those described in FIG. Limit ⁱ
L in the priority table 601 indicated by the index i
It is the value of the limit (set clock value), and if i = 0, the limit value of 601a is 60, and if i = 3, the limit of 601d is 30.

Next, the processing of the CPU clock determination unit 107 in the third embodiment will be described with reference to FIGS. 6 and 7.
Step 701 is initialization for the following processing.
In step 702, the range of index i is checked, and in step 703, the i-th ready queue 20 is checked.
Checking if there is a task in 2. If there is no task in the ready queue 202 in step 703, the process proceeds to step 704 and the next ready queue 2
Advance index i by one to check 02,
Return to step 702. If there is a task in the ready queue 202 in step 703, the process proceeds to step 705. In Step 705, the Limit value of the priority table 601 indicated by the index i is put into clock, and in Step 706, the value is set in the CPU clock control hardware 108.

It should be noted that the termination of the loop processing when the ready queue 202 in which a task exists is found in step 703 is because a normal system requires a faster CPU clock for higher priority processing. , The index i = 0 is sequentially checked, and the first determination of No in step 703 indicates that the ready queue 202 in which a task exists has the highest priority,
This is because the point where the fastest CPU clock is required is detected.

With the above processing, the higher the priority task in the ready queue 202, the higher the CPU clock can be made to operate, and the CPU clock value to be operated can be set for each priority. It is possible to make appropriate adjustments to the importance and urgency of processing and power saving according to the actual condition of the system and the assignment of priority to tasks.

The set clock value (Limit value) held in the priority table can be changed depending on the operating status of the computer. It is desirable that an interface is prepared for the user to change the set clock value.

As described above, in the power saving control system of this embodiment, the CPU clock value to be operated, which is set in advance for each priority, is added to the priority table, and the priority is set for each priority. It is characterized in that it is operated with the CPU clock generated.

Fourth Embodiment Next, a fourth embodiment will be described. The configuration of the power saving control system of this embodiment is the same as the block diagram shown in FIG. FIG. 8 is a diagram showing an example of contents of the priority table 801, the ready queue 202, the boundary value table 204, and the CPU clock table 203 in the fourth embodiment. In FIG. 8, 2
02 to 204 are the same as those in FIG. However, the way of connecting tasks in the ready queue 202 is different from that in FIG. Reference numeral 801 is a priority table similar to 201 in FIG. 2, but its constituent elements are a weighting value W when calculating the CPU load value for each priority, and a CPU clock value to operate for each priority. Limit is stored.

FIG. 9 is a flowchart showing the processing of the CPU clock determining unit in the fourth embodiment. In FIG. 9, prio_max, prio ⁱ , and list_no ⁱ
And Limit ⁱ have the same meaning as described in FIGS. 3 and 7.

Next, the processing of the CPU clock determining unit in the fourth embodiment will be described with reference to FIGS. In addition,
Steps 304 and 306 to 307 in FIG. 9 are the same as those in the first embodiment, and step 503 is the same as those in the second embodiment, and therefore their explanations are omitted. Step 901 is initialization for the following processing. In step 902, the range of index i is checked, and in step 903, the i-th ready queue 2 is checked.
It is checked whether the task exists in 02. Step 904 is a ready queue 202 in which a task exists.
Of these, it is a process for obtaining the maximum CPU clock value requested by Limit. Steps 902 to 3
By the loop processing of 04, the maximum values Base and C of the request clock in the ready queue 202 in which the task exists
The PU load value Total is obtained and the routine proceeds to step 907.

In step 907, the minimum CPU load value requiring the Base CPU clock, that is, an appropriate value in the clock boundary value table 204 is obtained. For example, if Base = 50, then 10 and Base = 4.
If 0, 5 is obtained. Next, in step 908, the CPU load value obtained in step 907 and 902 to 304
The CPU load value in consideration of the Limit set for each priority is obtained by adding the Total obtained in the loop processing. Next, in steps 306 and 307, the CPU to operate based on the Total obtained in step 908
Find the clock, CPU clock control hardware 1
It will be set to 08.

In the fourth embodiment, the priority table 801 has the weight value W, but like the priority table 601 shown in the third embodiment, the priority table 801 does not have the weight value W. It is also possible to calculate the CPU load value by using.

As described above, in this embodiment, in addition to the power saving control method of the first embodiment,
It is characterized in that a load is weighted and a preset CPU clock value to be operated is given to each priority.

Embodiment 5. A processing flow of another embodiment of the present invention is shown in FIG. The difference between FIG. 10 and FIG. 9 is that in Step 1001, Limit 0
Check and if not 0 (ie Limi
If t has been set) the loop processing is terminated and step 9 is executed.
The point is to proceed to 07. This is because in a normal real-time system, not all processing is time-constrained, and there are many tasks that do not need to set Limit.

By the processing in the above fourth and fifth embodiments,
The more tasks that have high priority in the ready queue, the higher the CP.
Since the CPU load value can be set for each priority and the CPU clock value to be operated for each priority can be set while operating with the U clock.
It is possible to make appropriate adjustments to the importance and urgency of processing and power saving according to the actual situation of the real-time system and the assignment of priority to tasks.

Sixth Embodiment Next, a fifth embodiment will be described. The configuration of the power saving control system of this embodiment is the same as the block diagram shown in FIG. FIG. 11 shows
FIG. 28 is a diagram showing a processing flow of an insert / delete function to a ready queue for calling a CPU clock determination unit in the fifth embodiment.

In the queue insertion processing, step 110
At 1, the position of the priority table is obtained from the priority of the task to be inserted. Generally, the priority table is an array, and the smaller the numerical value of priority, the higher the priority.
[(Task priority) -1] is an index as an array of the priority table. In some cases, the index 0 of the priority table is reserved and the task priority is directly used as the index of the priority table. In this embodiment, the table is 0 (zero).
The case of origin is assumed. Next, step 110
In 2, the task is inserted at the end of the ready queue pointed to by the priority table obtained in 1101, and in step 1103 the CPU clock determination unit 107
Is called. In step 1102, the task is inserted into the ready queue, and the first to fifth embodiments are executed.
It goes without saying that the value of list_no ⁱ in step 1 is incremented.

In the process of deleting from the queue, step 11
At 04, the position of the priority table is obtained from the priority of the task to be deleted. The method of obtaining the position of the priority table is the same as the process of inserting into the queue. Next, Step 1105
Delete the task from the ready queue at step 110
The CPU clock determining unit is called at 6. Needless to say, in step 1105, the task is deleted from the ready queue and the value of list_no ⁱ in the first to fifth embodiments is decremented.

Next, the processing flow of the CPU clock determining unit in the sixth embodiment will be described with reference to FIG. Figure 1
2 shows a processing flow chart of the CPU clock determination unit 107 operating using the priority table 201, the ready queue 202, the clock boundary value table 204, and the CPU clock table 203 used in the first embodiment shown in FIG. There is. Although the second to fifth embodiments have slightly different processing flows, they can be analogized from FIGS. 5, 7, 9, and 10.

In FIG. 12, steps 305 to 307.
Is the same as that of the same step number in FIG. In step 1201, this processing flow is the ready queue 202.
It is determined from when it is called into the ready queue 202 or when it is called from the ready queue 202. The criterion for judgment is C
It is possible with the parameter passed to the PU clock determination unit. Step 1 if called from the queue insertion process
The process proceeds to 202 and the CPU according to the priority of the inserted task
Add the load value to Total. On the other hand, if called by the queue deletion process, the process proceeds to step 1203,
The CPU load value according to the priority of the deleted task is To
Subtract from tal. After that, in steps 305 to 307, the operation clock of the CPU is determined by the Total value recalculated in steps 1202 and 1203,
Set to hardware.

By the above processing, the CPU load value that determines the operating clock of the CPU is performed during the operation of the ready queue that influences the CPU load value, so that the change in the CPU load value can be immediately reflected in the CPU clock. Along with C
The processing of the PU clock determination unit 107 can be reduced.

As described above, in this embodiment, in addition to the power saving control methods of the first to fourth embodiments, the CPU clock determining unit is executed at the time of ready queue operation to determine the CPU clock. It is characterized by reducing the processing of parts.

Embodiment 7. Next, a seventh embodiment will be described. The configuration of the power saving control system of this embodiment is the same as the block diagram shown in FIG. Figure 13
20 shows an interrupt processing flow when an interrupt is generated from the timer 109 of the time management unit 104 in the operating system in the seventh embodiment. Step 1301
Then, the processing when a timer interrupt occurs in a normal operating system is performed. For example, there is a task timeout detection. Next, in step 1302, the CPU
By calling the clock determination unit 107, the operation clock of the CPU is recalculated by using the timer interrupt processing that is generated by the normal operating system and that occurs at regular time intervals. The processing flow of the CPU clock determination unit is the same as any one of FIGS. 3, 5, 7, 9, and 10.

By the above processing, the CPU load value that determines the operating clock of the CPU is recalculated at regular time intervals, thereby eliminating the need for recalculation at the time of ready queue operation, which occurs very frequently, and makes the operating system of the operating system unnecessary. The load can be reduced.

As described above, in this embodiment, in addition to the power saving control methods of the first to fourth embodiments, the CPU clock determining unit is periodically executed at a constant time interval, It is characterized by not requiring additional processing when operating the ready queue.

Embodiment 8. Next, an eighth embodiment will be described. The eighth embodiment is composed of a flow at the time of inserting a queue in FIG. 11 and a flow of recalculating a CPU load value at a constant time interval using a timer interrupt in FIG.

With the above processing, while maintaining the effect of reducing the load on the operating system in the seventh embodiment, the CPU load value is recalculated when the task is inserted into the ready queue, so that the CPU load can be immediately increased. It becomes possible to deal with it, and it is possible to avoid deterioration of responsiveness to real-time processing.

As described above, in this embodiment, in addition to the power-saving control methods of the first to fourth embodiments, the CPU clock determining unit is configured to periodically perform the ready queue operation and at regular time intervals. The execution is characterized by reducing the processing addition at the time of the ready queue operation and reducing the processing amount of the CPU clock determining unit.

[0064]

According to the present invention, the priority of tasks and
The operation clock of the task can be determined in consideration of the number of tasks in the waiting state. Therefore, the operation clock can be flexibly determined even when a plurality of tasks are in a waiting state.

Further, by providing the boundary value table, it is possible to determine the operation clock using at least the load value calculated using the task priority and the number of tasks in the waiting state as elements. In addition, the task execution status can be easily improved by changing the reference value according to the operating status of the computer.

Further, by having the weighted value in the priority table, the operation clock of the task can be determined according to the intention of the user. Also, by changing the weighting value, it becomes easy to determine the operation clock that matches the operating status of the computer.

Further, since the priority table has a set clock value (Limit value) in advance, it is possible to make adjustments according to the operating status of the computer and the degree of task priority allocation.

By having a task management section,
The start and end of the task can be reflected in the priority table, which contributes to the determination of a more appropriate operation clock.

Further, by activating the clock determining unit when the number of tasks in the priority table is updated, the operation clock corresponding to the task execution status can be changed.

Further, by periodically activating the clock determining unit, it becomes possible to regularly update the operating clock of the processor according to the operating status of the computer.

[Brief description of drawings]

FIG. 1 is a block diagram showing functions of a power saving control system of the present invention.

FIG. 2 is a priority table 20 according to the first embodiment.
1, ready queue 202, boundary value table 204, CP
The figure showing the example of the content of the U clock table 203.

FIG. 3 is a flowchart showing a process of a CPU clock determination unit according to the first embodiment.

FIG. 4 is a priority table 40 according to the second embodiment.
1, ready queue 202, boundary value table 204, CP
The figure showing the example of the content of the U clock table 203.

FIG. 5 is a flowchart showing a process of a CPU clock determining unit according to the second embodiment.

FIG. 6 is a priority table 60 according to the third embodiment.
1, ready queue 202, CPU clock table 20
The figure showing the content example of 3.

FIG. 7 is a flowchart showing a process of a CPU clock determining unit according to the third embodiment.

FIG. 8 is a priority table 80 according to the fourth embodiment.
1, ready queue 202, boundary value table 204, CP
The figure showing the example of the content of the U clock table 203.

FIG. 9 is a flowchart showing the processing of the CPU clock determining unit in the fourth embodiment.

FIG. 10 is a diagram showing a processing flow of a CPU clock determination unit according to the fifth embodiment.

FIG. 11 is a function 103 of inserting and deleting into a ready queue for calling a CPU clock determining unit according to the fifth embodiment.
Of the processing flow of FIG.

FIG. 12 is a processing flowchart of a CPU clock determining unit according to the sixth embodiment.

FIG. 13 is a timer hardware 10 of the time management unit 104 in the operating system according to the seventh embodiment.
9 is an interrupt processing flow chart when an interrupt from 9 occurs.

[Explanation of symbols]

101 Operating System, 102 Task Management Unit, 103 Ready Queue and Function to Operate Ready Queue, 105 CPU Clock Table, 106 Clock Boundary Value Table, 107 CPU Clock Determining Unit, 108 CPU Clock Control Hardware, 10
9 timer, 201, 401, 601, 801 priority table, 202 ready queue, 203 CPU clock table, 204 boundary value table.

Claims (10)

[Claims] 1. A power saving control method for controlling an operation clock of a processor for operating a plurality of tasks, wherein a priority table holding a plurality of priorities and the number of tasks waiting to be executed by each of the plurality of priorities. And a clock table that holds a plurality of operating clock values that can be set to the processor, read the plurality of priorities and the number of tasks from the priority table, and read out the plurality of priorities and tasks. And a clock determining unit for selecting an operation clock value from the clock table using the calculated load value and setting the selected operation clock value to the processor. A power-saving control method comprising: 2. The power saving control system further comprises a reference value table holding a reference value for determining an operation clock of the processor, and the clock determination unit reads the reference value from the reference value table, The power saving control system according to claim 1, wherein the operation clock is selected using the reference value and the load value. 3. The priority table further holds a weighting value corresponding to each of the plurality of priorities, and the clock determination unit stores the plurality of priorities, the number of tasks, and the weighting value. The power saving control system according to claim 1, wherein the load value is calculated using the load value. 4. The priority table further holds set clock values corresponding to each of the plurality of priorities, and when the clock determination unit calculates the load value,
2. The set clock value is used.
The power saving control method according to any one of 1 to 3. 5. The power saving control method further inputs either a task name of which execution is requested or a task name of which execution has been completed, acquires a priority from the input task name, and acquires the acquired priority. 5. The power saving control method according to claim 1, further comprising a task management unit that updates the number of tasks held in the priority table by using the task management unit. 6. The power saving control system according to claim 5, wherein the power saving control system activates the clock determining unit when the task management unit updates the number of tasks held in the priority table. control method. 7. The power saving control method activates the clock determination unit at a predetermined cycle.
6. The power saving control method according to any one of 1 to 6. 8. A power-saving control method for controlling an operation clock of a processor for operating a plurality of tasks, wherein a plurality of priorities and the number of tasks waiting to be executed by priorities corresponding to the plurality of priorities are set. A priority table storing step of storing in the priority table; a clock table storing step of storing a plurality of operation clock values that can be set in the processor in the clock table; The number of tasks and the number of tasks that have been read are used to calculate the load value applied to the processor using the read multiple priorities and the number of tasks, and the operation clock value is selected from the clock table using the calculated load value. And a clock determining step of setting a selected operation clock value to the processor. Way. 9. A program for causing a computer to execute power saving control for controlling an operation clock of a processor that operates a plurality of tasks, and waits for execution by a plurality of priorities and priorities corresponding to the plurality of priorities, respectively. A priority table storing process for storing the number of tasks in the priority table, a clock table storing process for storing a plurality of operation clock values that can be set in the processor in the clock table, and And the number of tasks are read, the load value applied to the processor is calculated using the read multiple priorities and the number of tasks, and the calculated load value is used to operate from the clock table. It is equipped with a clock determination process that selects a clock value and sets the selected operating clock value to the processor. A program that causes a computer to execute power saving control. 10. A recording medium in which a program for causing a computer to execute power saving control for controlling operation clocks of a processor for operating a plurality of tasks is recorded, and a plurality of priorities and priorities corresponding to the plurality of priorities are provided. Priority table storage processing for storing the number of tasks waiting for execution in a priority table, clock table storage processing for storing a plurality of operation clock values that can be set in the processor in the clock table, and priority processing The plurality of priorities and the number of tasks from the degree table, using the plurality of read priority and the number of tasks, to calculate the load value applied to the processor, using the calculated load value, Select the operating clock value from the above clock table and set the selected operating clock value to the processor. A computer-readable recording medium having a program for causing a computer to execute power saving control, the recording medium including a clock determination process.