JP2002366252A - System and method for controlling operation frequency, portable information processing terminal and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately control the operation frequency of a processor. SOLUTION: A ROM 2 prestores an operation frequency data table showing the upper and lower limit thresholds of load quantity while associating the operation frequency data table with an operation frequency settable in a processor 1. In the operation frequency data table, the lower limit threshold of load quantity corresponding to one operation frequency being a higher frequency is set to be smaller than the upper limit threshold of load quantity corresponding to the other operation frequency being a lower frequency with respect to two larger and smaller adjacent operation frequencies settable in the processor 1. A frequency switching controlling part realized in such a manner that the processor 1 executes an operation program stored in the ROM 2 to start on OS compares a variable Total- tricks showing the load quantity of the processor with the upper and lower limit thresholds of load quantity corresponding to the current operation frequency and performs processing for changing the operation frequency in accordance with comparison results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an operating frequency control system, a portable information processing terminal, an operating frequency control method, and a program.

[0002]

2. Description of the Related Art Cellular phones and PDAs (Personal Digital
Assistant), CPU (Central Processing Unit) and MPU for portable information processing terminals such as notebook computers
A processor such as a (MicroProcessing Unit) can be driven by receiving power from a rechargeable battery (secondary battery) or the like.

As a technique for reducing the power consumption of a processor for such a portable information processing terminal, there is known an operating frequency control system for dynamically controlling the operating frequency of the processor. This operating frequency control system is realized, for example, by a processor activating an OS (Operating System, hereinafter referred to as “OS”).

[0004] The processing speed and power consumption of a processor change by switching the operating frequency, for example, as shown in FIG. Therefore, the operating frequency control system reduces the operating frequency when executing a relatively light-load application such as a program for displaying phonebook data, data indicating e-mail, a still image, or the like. Reduce power consumption. On the other hand, the operating frequency control system increases the operating frequency when executing a relatively heavy load application such as a program for reproducing a moving image or an audio so that the user does not feel uncomfortable. Control.

In order to realize such a function, the load of the processor is monitored at a predetermined timing, and each time a predetermined time elapses, the usage status of the processor is specified based on the monitored load, and the specified usage is specified. It is conceivable to switch the operating frequency of the processor according to the situation.

[0006]

Here, the following problems may occur depending on how the load is set as the threshold when the operating frequency of the processor is switched. That is, of the two operating frequencies that are large and small adjacent to each other among the operating frequencies that can be set for the processor, the lower limit threshold value of the load amount corresponding to one of the high operating frequencies is set to It is assumed that the upper limit threshold value of the corresponding load amount is matched. in this case,
When the load of the processor fluctuates near the threshold value, a phenomenon that the operating frequency of the processor is frequently switched occurs. Such a phenomenon is called overreaction, and there is a problem in that the processing for switching the operating frequency is frequently performed, and the operating efficiency of the processor is reduced.

The present invention has been made in view of the above situation, and provides an operating frequency control system, a portable information processing terminal, an operating frequency control method, and a program capable of appropriately controlling the operating frequency of a processor. The purpose is to:

[0008]

To achieve the above object, an operating frequency control system according to a first aspect of the present invention is an operating frequency control system for automatically switching an operating frequency of a processor, Storage means for storing in advance table data indicating an upper threshold value and a lower threshold value of a processor load amount in association with an operating frequency which can be set for the processor; a load amount detection means for detecting a load amount of the processor; With reference to the table data stored in the means, the processor load detected by the load detector is set to an upper threshold and a lower threshold of the processor load corresponding to the operating frequency currently set for the processor. Determining whether to change the operating frequency of the processor by comparing with at least one of Frequency control means for performing a process for changing the operating frequency of the processor when it is determined that the operating frequency of the processor, the table data stored in the storage means, The lower limit threshold value of the processor load corresponding to one of the higher operating frequencies is set smaller than the upper limit threshold of the processor load corresponding to the other operating frequency of the lower frequency. Has been characterized.

The load amount detecting means monitors the load amount of the processor at a predetermined timing, and integrates the monitored load amount every time a predetermined time elapses.
It is preferable that the frequency control means determines whether to change the operating frequency of the processor based on the load amount integrated by the load amount detection means.

The processor further includes timing detection means for detecting a task switching timing to be executed by the processor, and an execution start timing and an execution end timing of the interrupt processing, wherein the load amount detection means detects the timing detected by the timing detection means. It is desirable to monitor the amount of load on the processor by using the method.

The frequency control means determines that the load of the processor detected by the load detection means exceeds a processor load upper limit threshold corresponding to an operating frequency currently set for the processor. In this case, a process for clocking up the operating frequency of the processor to a higher frequency by one step is executed, and when it is determined that the operating frequency is lower than the lower threshold of the processor load, the operating frequency settable for the processor is Of these, it is desirable to execute processing for clocking down to the highest frequency at which the corresponding upper limit threshold of the load exceeds the processor load detected by the load detector.

A portable information processing terminal according to a second aspect of the present invention is a portable information processing terminal comprising a processor capable of switching an operating frequency, and a storage circuit for storing an operation program executed by the processor and data. The data stored in the storage circuit includes table data indicating an upper threshold and a lower threshold of a processor load amount associated with an operating frequency that can be set for the processor. A load amount detecting means for detecting a load amount by executing an operation program stored in the storage circuit, and a load detected by the load amount detecting means with reference to table data stored in the storage circuit. The amount is at least one of an upper threshold value and a lower threshold value of the processor load amount corresponding to the currently set operating frequency. By comparing Re or the other and,
Determine whether or not to change the operating frequency, frequency control means for performing a process for changing the operating frequency when it is determined to change, the table data stored in the storage circuit, The lower limit threshold value of the processor load corresponding to one of the higher operating frequencies corresponds to the other lower operating frequency of two operating frequencies that are larger and smaller than the operating frequencies that can be set for the processor. Is set to be smaller than the upper limit threshold value of the processor load.

An operating frequency control method according to a third aspect of the present invention is an operating frequency control method for automatically switching an operating frequency of a processor, the operating frequency control method corresponding to an operating frequency that can be set for the processor. Table data indicating an upper limit threshold and a lower limit threshold of the load amount, and a processor load corresponding to one of the higher operating frequencies among two operating frequencies that are larger and smaller than the operating frequencies that can be set for the processor. The table data in which the lower threshold of the amount is set smaller than the upper threshold of the processor load corresponding to the other operating frequency that is the low frequency is stored in a predetermined storage circuit in advance, and the processor executes the operation program. Thus, the load amount is detected, and the load amount is detected with reference to the table data stored in the storage circuit. The load amount is compared with at least one of the upper threshold value and the lower threshold value of the processor load amount corresponding to the currently set operating frequency, and it is determined whether or not to change the operating frequency. ,
Executing a process for changing the operating frequency.

According to a fourth aspect of the present invention, there is provided a program for causing a computer to store in advance table data indicating an upper limit threshold and a lower limit threshold of a processor load amount in association with an operating frequency settable for a processor. Means, a load amount detecting means for detecting a load amount of the processor, and table data stored in the storage means, and the load amount of the processor detected by the load amount detecting means is provided to the processor. By comparing with at least one of the upper threshold value and the lower threshold value of the processor load amount corresponding to the set operating frequency, it is determined whether or not to change the operating frequency of the processor. The storage means, which functions as frequency control means for executing processing for changing the operating frequency of the processor; The stored table data indicates that the lower threshold value of the processor load amount corresponding to one of the operating frequencies that is a high frequency is lower than the lower frequency of two operating frequencies that are larger and smaller than the operating frequencies that can be set for the processor. Is set to be smaller than the upper limit threshold value of the processor load corresponding to the other operating frequency.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an operating frequency control system according to an embodiment of the present invention will be described in detail with reference to the drawings, taking a case where the present invention is applied to a portable information processing terminal 100 as an example.

The portable information processing terminal 100 includes, for example,
Mobile phones, PDAs (Personal Digital Assistants),
It is a terminal device such as a notebook personal computer that can operate even when disconnected from a commercial power supply, and has a configuration as shown in FIG. As shown, the portable information processing terminal 100 includes a processor 1 and a ROM (Read Only Memory).
y) 2, RAM (Random Access Memory) 3, input unit 4, display control unit 5, display unit 6, power supply control unit 7
And a power supply 8.

The processor 1 is, for example, a CPU (Central
Processing Unit) or MPU (Micro Processin)
g Unit), etc., and the portable information processing terminal 100
This is for controlling the entire operation. Processor 1
Reads a program recorded in, for example, the ROM 2 under the control of an OS (Operating System) and executes various applications. Note that the processor 1 may read a program from an arbitrary recording medium such as a magnetic disk device (not shown) and execute an application or the like. Further, the processor 1 includes a tick counter 10 that counts up for each tick. Here, one tick corresponds to one tick supplied to the processor 1.
One clock signal. That is, the tick counter 10 counts up, for example, by counting the number of clocks at the timing of the rising edge of the clock signal supplied to the processor 1.

The ROM 2 is a read-only storage circuit for storing operation programs such as a device driver, a loader program, an OS, and an application program. The ROM 2 stores an operating frequency data table 11 as illustrated in FIG. 2A in advance.

The operating frequency data table 11 stores an operating frequency to be set for the processor 1 and a voltage to be supplied to the processor 1 based on a task executed by the processor 1 within a predetermined period and a tick value used for interrupt processing. It contains data for specifying the size of For example, the operating frequency data table 11 includes “operating frequency” indicating an operating frequency that can be set for the processor 1, “TICKmax” indicating an upper threshold of a tick value corresponding to the operating frequency, “TICKmin” indicating a lower threshold, It is composed of data such as “supply voltage” indicating the magnitude of the supply voltage to the processor 1.

In the operating frequency data table 11, the lower limit threshold value of the load corresponding to one of the high operating frequencies is set to the low operating frequency for two operating frequencies that are large and small adjacent to each other and can be set for the processor 1. Is set smaller than the upper limit threshold value of the load amount corresponding to the other operation frequency.

The RAM 3 is a rewritable storage circuit that provides a work area when the processor 1 executes a program and enables temporary storage of data and the like. For example, the RAM 3 stores an operating frequency request management table 12 as illustrated in FIG.

The operating frequency request management table 12 is a table for managing the operating frequency requested by the user program executed by the processor 1, and includes a management number for identifying the operating frequency for each request from the user program. The data includes a “management number” indicating the requested operation frequency and a “requested frequency” indicating the requested operation frequency.

The input unit 4 includes, for example, a keypad, a mouse,
The portable information processing terminal 100 is constituted by a pointing device and the like, and is used for inputting instruction information for instructing the operation of the portable information processing terminal 100, data indicating characters and numerals, and the like.

The display control unit 5 is, for example, a VRAM (Video-
RAM), an LCD (Liquid Crystal Display) driver, and the like, for controlling the operation of the display unit 6 in accordance with image data and the like received from the processor 1.

The display unit 6 is composed of, for example, an LCD panel or the like, and displays an image or the like under the control of the display control unit 5.

The power supply control section 7 is constituted by, for example, a switching regulator and the like, and regulates the power supply voltage supplied from the power supply 8 to a predetermined voltage value and supplies it to the processor 1 and the like. Here, the power supply control unit 7 adjusts the supplied power by changing the magnitude of the voltage supplied to the processor 1 to enable control of the operating frequency. When the portable information processing terminal 100 is connected to a charging device (not shown), the power control unit 7 notifies the processor 1 that the portable information processing terminal 100 has been set to the charging device, and starts charging the power source 8. On the other hand, when the connection between the portable information processing terminal 100 and the charging device is released, the power control unit 7 notifies the processor 1 of that fact.
And the charging of the power supply 8 ends.

The power supply 8 is constituted by a rechargeable battery (secondary battery) such as a lithium ion battery or a nickel hydride ion battery, for supplying electric power for driving the portable information processing terminal 100. is there.

Next, in the portable information processing terminal 100 having the above configuration, the logical configuration of the operating frequency control system 101 realized by the processor 1 executing the operation program stored in the ROM 2 and activating the OS will be described. This will be described with reference to FIG. As shown in the figure, the operating frequency control system 101 includes a load amount detection unit 20;
It comprises a frequency switching control unit 21, a timing detection unit 22, a monitor flag 23, and an operation mode setting processing unit 24.

The load amount detecting section 20 includes a tick counter 1
A process for detecting the load amount applied to the processor 1 using the count value of 0 is executed. For example, the load amount detection unit 20 obtains a tick value required for a task executed within a certain period of time or an interrupt process by integrating the count value (tick value) of the tick counter 10 and a variable Tota.
Set as l_ticks. Here, the load amount detection unit 20
Is a variable Tick indicating the count value of the tick counter 10.
Using _Reg_OLD and the variable Tick_Reg, a process for integrating the count value is executed.

The variable Tick_Reg_OLD indicates the count value of the tick counter 10 at the timing when the processor 1 switches the process to the task currently being executed or when the execution of the interrupt process is started. Also, the variable Tick_Reg is
This shows the current count value of the tick counter 10.

The frequency switching control section 21 includes a load amount detecting section 2
Switching of the operating frequency of the processor 1 is controlled based on the variable Total_ticks set by 0. When switching the operating frequency of the processor 1, the frequency switching control unit 21 instructs the power supply control unit 7 to switch the magnitude of the power supply voltage supplied to the processor 1. At this time, the frequency switching control section 21 refers to the operating frequency data table 11 stored in the ROM 2 and specifies the magnitude of the power supply voltage supplied from the power supply control section 7 to the processor 1.

The timing detecting section 22 has a performance monitor / timer 30, and detects the timing at which the load amount detecting section 20 and the frequency switching control section 21 execute various processes. That is, when the timing detection unit 22 detects the switching timing of the task to be executed by the processor 1 and the execution start / end timing of the interrupt processing, the timing detection unit 22 executes the processing for integrating the count value of the tick counter 10 into a load. It instructs the amount detection unit 20. In addition, the timing detection unit 22 determines a predetermined time T
Performance monitor timer 3 that _mon has passed
0, the processing for automatically switching the operating frequency in accordance with the usage status of the processor 1 is executed.
It instructs the frequency switching control unit 21.

The performance monitor timer 30 detects that a predetermined time T _{mon, which} is a cycle for evaluating the use state of the processor 1, has elapsed. The performance monitor timer 30 changes the operating frequency according to the use state of the processor 1. It is reset every time the processing for switching is executed, and the measurement of the elapsed time is started again (restarted).

The monitor flag 23 indicates that the portable information processing terminal 1
00 indicates whether or not the operation mode is an operation mode in which the operation frequency is automatically switched according to the use state of the processor 1. That is, the monitor flag 23 is “ON” when the portable information processing terminal 100 is in an operation mode in which the operation frequency is automatically switched by monitoring the load of the processor 1. Further, the monitor flag 23 is “OFF” when the operation mode is such that the processor 1 operates at the operation frequency according to the instruction from the user program executed by the processor 1.

The operation mode setting processing section 24 sets the operation mode of the portable information processing terminal 100 by executing a predetermined initialization process when the power supply 8 is turned on.

The operation of portable information processing terminal 100 according to the embodiment of the present invention will be described below.

In the portable information processing terminal 100, the operating frequency control system 101 sets the monitor flag 23 to "
When it is “ON”, that is, in an operation mode in which the operation frequency is automatically switched according to the use state of the processor 1, the load amount of the processor 1 is detected by integrating the count value of the tick counter 10. .

For example, the operation mode setting processing section 24 performs processing corresponding to the instruction information input from the input section 4 when the power supply 8 is instructed, the operation mode when the power supply 8 was last turned off, and the like. Is executed, and the monitor flag 23 is set to “O”
N ”is determined. Operation mode setting processing unit 2
4 determines that the variable Total_ticks, the variable Tick_Reg, and the variable Tick_Reg_OL
D is set to "0", and initialization processing such as resetting the performance monitor timer 30 and starting measurement of elapsed time is executed. Thereafter, the operation mode setting processing unit 24 sets the monitor flag 23 to “ON”.

When the monitor flag 23 is set to "ON", the timing detection section 22 detects the task switching timing and the execution start / end timing of the interrupt processing, and detects the load amount at each detected timing. A command to add the count value of the tick counter 10 to the unit 20 is sent. The load amount detection unit 20 calculates the variable Tick_Reg from the variable Tick_Reg.
The value obtained by adding the current value of the variable Total_ticks to the value obtained by subtracting eg_OLD is newly set as a variable Total_ticks, and the tick value corresponding to the load of the processor 1 is integrated.

When the performance monitor timer 30 detects that the predetermined time T _mon has elapsed, the timing detection section 22 starts executing the operation frequency automatic switching process shown in the flowchart of FIG. Is sent to the frequency switching control unit 21. The operation frequency automatic switching process is a process for automatically switching the operation frequency in accordance with the usage status of the processor 1. Hereinafter, the operation frequency automatic switching process shown in the flowchart of FIG. 4 will be described.

When the operating frequency automatic switching process is started in response to a command from the timing detecting unit 22, the frequency switching control unit 21 determines whether or not the processor 1 is currently executing a task (step S1). .

When frequency switching control section 21 determines that the task is being executed (YES in step S 1),
A process for integrating Total_ticks is executed (step S2). That is, the frequency switching control unit 21 sets the variable Ti
To the value obtained by subtracting the variable Tick_Reg_OLD from ck_Reg, the variable To
Add the current value of tal_ticks to a new variable Total_t
Set as icks.

On the other hand, if the frequency switching control section 21 determines that the processor 1 is not executing a task (NO in step S1), it skips the processing in step S2.

After that, the frequency switching control unit 21 associates the upper limit threshold and the lower limit threshold of the load amount corresponding to the current operation frequency in the processor 1, that is, the current operation frequency in the operation frequency data table 11. "TICKmax" and "TICKmin" are specified (step S3).

The frequency switching control unit 21 uses the variable Total_tick
s is the upper threshold of the load corresponding to the current operating frequency ("T
(The value of “ICKmax”) is determined (step S4).

The frequency switching control unit 21 includes a variable Total_tick
If it is determined that s exceeds the upper limit of the load amount (step
(YES in step S4), can be set for processor 1.
Only one step from the current operating frequency
High frequency is set frequency F _CPUSet as
Step S5). The frequency switching control unit 21 will be described later.
An operating frequency clock up process is executed (step S
6) Clock up the operating frequency of the processor 1
You. Note that the clock that defines the operating frequency of the processor 1 is
The tick signal is counted up by the tick counter 10.
It is different from the clock signal,
It is supplied to each part of the terminal 100.

On the other hand, the frequency switching control unit 21
When it is determined that l_ticks is equal to or less than the upper limit of the load (NO in step S4), the variable Total_ticks sets the lower limit of the load corresponding to the current operating frequency (“TICKmin”).
Is determined (step S7).

The frequency switching control unit 21 includes a variable Total_tick
When it is determined that s is less than the lower limit of the load amount (YES in step S7), the corresponding upper limit threshold value of the load amount is set to the variable To among the operating frequencies that can be set for the processor 1.
The highest frequency exceeding tal_ticks is set as the set frequency F _cpu (step S8). Further, the frequency switching control unit 21 executes an operating frequency clock down process described later (step S9), and clocks down the operating frequency of the processor 1.

On the other hand, the frequency switching control unit 21
If it is determined that l_ticks is equal to or greater than the lower limit of the load amount (NO in step S7), it is determined that there is no need to change the operating frequency of processor 1, and the processing in steps S8 and S9 is skipped.

After that, the frequency switching control unit 21
Initialize by setting Total_ticks to “0” (step S
10). Further, the frequency switching control unit 21 sets the variable Tick_Reg
Similarly, the variable Tick_Reg_OLD is also set to “0”,
Initialize (step S11).

The frequency switching control section 21 resets the performance monitor timer 30, starts (restarts) the measurement of the elapsed time again (step S12), and ends the operation frequency automatic switching processing.

Next, the operating frequency clock-up processing executed by the frequency switching control section 21 in step S6 of the above-described automatic operating frequency switching processing will be described with reference to the flowchart of FIG.

The frequency switching control section 21 sets the set frequency F
Supply voltage value V _cc supplied to processor 1 corresponding to _cpu
Is specified (step S21). At this time, the frequency switching control unit 21 refers to the operating frequency data table 11 stored in the ROM 2 and specifies the magnitude of the voltage supplied to the processor 1 corresponding to the set frequency F _cpu . That is, the frequency switching control unit 21 sets, as the supply voltage value _Vcc , the data “supply voltage” included in the operation frequency data table 11 that corresponds to the data “operation frequency” specified as the set frequency F _cpu. Identify.

The frequency switching control section 21 determines whether or not the specified supply voltage value _Vcc is different from the magnitude of the voltage currently supplied from the power supply control section 7 to the processor 1 (step S22).

The frequency switching control section 21 supplies the supply voltage _Vcc
Is different from the current supply voltage (YES in step S22), the power supply control unit 7 is controlled to change the magnitude of the voltage supplied to the processor 1 in accordance with the supply voltage value _Vcc. (Step S23).

On the other hand, the frequency switching control unit 21 determines that the supply voltage value V _cc is not different from the current supply voltage value, that is, the supply voltage value V _cc matches the current supply voltage value. When it is determined (N in step S22)
O), the process of step S23 is skipped.

After that, the frequency switching control section 21 changes the operating frequency of the processor 1 in accordance with the set frequency F _cpu to clock up (step S24), and ends the operating frequency clock up processing.

Next, the operating frequency clock down processing executed by the frequency switching control section 21 in step S9 of the above-described automatic operating frequency switching processing will be described with reference to the flowchart of FIG.

The frequency switching control section 21 has a setting frequency F
Supply voltage value V _cc supplied to processor 1 corresponding to _cpu
Is specified (step S31). At this time, the frequency switching control unit 21 refers to the operating frequency data table 11 stored in the ROM 2 and specifies the magnitude of the voltage supplied to the processor 1 corresponding to the set frequency F _cpu . That is, the frequency switching control unit 21 sets, as the supply voltage value _Vcc , the data “supply voltage” included in the operation frequency data table 11 that corresponds to the data “operation frequency” specified as the set frequency F _cpu. Identify.

At this time, the frequency switching control unit 21
The clock is reduced by changing the operating frequency of the processor 1 according to the set frequency F _cpu (step S3).
2).

After that, the frequency switching control unit 21 sends the specified supply voltage value _Vcc from the power supply control unit 7 to the processor 1.
It is determined whether or not the voltage is different from the magnitude of the voltage currently being supplied (step S33).

The frequency switching control section 21 supplies the supply voltage _Vcc
Is different from the current supply voltage (YES in step S33), the power supply control unit 7 is controlled to change the magnitude of the voltage supplied to the processor 1 in accordance with the supply voltage value _Vcc. (Step S34), and the operation frequency clock down process ends.

On the other hand, the frequency switching control unit 21 determines that the supply voltage value V _cc is not different from the current supply voltage value, that is, the supply voltage value V _cc matches the current supply voltage value. When it is determined (N in step S33)
O), the process of step S34 is skipped, and the operating frequency clock down process ends.

As described above, the operating frequency control system 101 can automatically switch the operating frequency according to the use status of the processor 1 provided in the portable information processing terminal 100.

Here, in the operating frequency data table 11, the lower limit of the load amount corresponding to one of the higher operating frequencies is determined for two operating frequencies that are larger or smaller than the operating frequencies that can be set for the processor 1. It is assumed that the threshold value and the upper limit threshold value of the load amount corresponding to the other operating frequency that is a low frequency are made to match. For example, the operating frequency that can be set for the processor 1 is 400 MHz.
It is assumed that z and 600 MHz exist, and no frequency that can be set for the processor 1 exists at a frequency between these two operating frequencies. That is, 400 MHz and 600 MHz are two operating frequencies that are larger and smaller than each other among the operating frequencies that can be set for the processor 1.
Also, the upper limit threshold of the load amount corresponding to 400 MHz is set to TICK
max (400 MHz), and the lower limit threshold of the load amount corresponding to 600 MHz is set to TICKmin (600 MHz). At this time, TICKmax (400
(MHz) = TICKmin (600 MHz).

In this case, TICKmax (400 MHz) = TICKmin (600
MHz), the operating frequency of the processor 1 must be frequently clocked up or down when the load of the processor 1 changes near the value of (MHz).
For example, as shown in FIG. 7, the predetermined time T _mon
Timing t ₁₀ but coming to every elapsed, t _20, ..., t
_{At 80} , the operation frequency automatic switching process described above is executed, and the load amount specified by the variable Total_ticks is set to TICKmax.
(400 MHz) = It is assumed that the frequency fluctuates around TICKmin (600 MHz). At this time, 600MH frequency switching controller 21, at a timing t ₃₀ the operating frequency of the processor 1 from 400MHz
After changing the z, returned to 400MHz at a timing t _40, change to 600MHz at a timing t _50, change to 400MHz at a timing t _60, it is changed to 600MHz at a timing t _70. As described above, since the frequency switching control unit 21 must frequently switch the operating frequency of the processor 1, the number of executions of the above-described operating frequency clock-up processing and operating frequency clock-down processing increases, and the utilization efficiency of the processor 1 increases. Decrease.

Therefore, the operating frequency control system 101 according to the embodiment of the present invention, in the operating frequency data table 11, sets the load amount corresponding to one of the higher operating frequencies for two operating frequencies adjacent to each other. A difference is provided between the lower limit threshold value and the upper limit threshold value of the load amount corresponding to the other operation frequency that is the low frequency.

For example, operating frequencies that can be set for the processor 1 are 50 MHz, 150 MHz, 400 MHz,
MHz, 600 MHz, and 800 MHz. In this case, in the operating frequency data table 11, “TICKmax” and “TICKmin” are set as shown in FIG. Here, TICKmax (Freq) and TIC shown in FIG.
Kmin (Freq) is (Freq = 50MHz, 150MHz, 400MHz, 600MHz
z, 800 MHz) are the upper and lower thresholds of the load amount corresponding to the respective operating frequencies Freq. As shown in FIG. 8, in the operating frequency data table 11, for two operating frequencies that are larger or smaller than the operating frequency that can be set for the processor 1, the load amount corresponding to one of the higher operating frequencies is determined. The lower threshold is set to a value smaller than the upper threshold of the load amount corresponding to the other operating frequency that is the low frequency.

In step S3 of the operating frequency automatic switching process shown in the flowchart of FIG. 4 described above, the frequency switching control section 21 sets the upper limit threshold value of the load amount corresponding to the operating frequency currently set for the processor 1 (" TICKma
The value of “x”) and the lower threshold (the value of “TICKmin”) are obtained from the operating frequency data table 11 and compared with the load amount specified by the variable Total_ticks.

For example, as shown in FIG.
_The timing t ₁₁ , t ₂₁ , which arrives every time _mon elapses,
.., At _t81 , the operating state of the processor 1 is specified and the operating frequency and the supply voltage are switched.

In this case, at timings t ₁₁ and t ₂₁ , the operating frequency of the processor 1 is set to 400 MHz, and at timing t ₃₁ , the load indicated by the variable Total_ticks changes to the Is determined to exceed the upper limit threshold value TICKmax (400 MHz). Based on this determination result, the frequency switching controller 21, the operating frequency automatic switching processing executed at a timing t _31, changes the operating frequency of the processor 1 to 600 MHz.

Thereafter, in the operating frequency automatic switching process executed at timings t _{41 to} t _{61, the} operating frequency of the processor 1 is not changed, and the state set to 600 MHz is maintained. Also, the operating frequency automatic switching process performed at the timing t _71, the variable Total_tick
It is determined that the load indicated by s is less than the lower limit TICKmin (600 MHz) of the load corresponding to the operating frequency of 600 MHz, and the frequency switching control unit 21 changes the operating frequency of the processor 1 to 400 MHz. As described above, the threshold value of the load amount for clocking up the operating frequency (upper limit threshold value)
And the threshold value (lower threshold value) of the load amount to be clocked down, it is possible to prevent the frequent switching operation of the operating frequency when the load amount fluctuates near the threshold value.

That is, for example, as shown in FIG.
Even if the load indicated by Total_ticks changes,
Except to change at a timing t ₅₂ from 400MHz to 600MHz will not be operating frequency of the processor 1 is changed. Here, the time change of the load amount shown in FIG. 10 is the same as the time change of the load amount shown in FIG.
By reducing the number of times the switching operation of the operating frequency is performed in this manner, it is possible to prevent a reduction in the processing capability of the processor 1 and an increase in power consumption.

As described above, according to the present invention,
In the operating frequency data table 11, the lower limit threshold of the load amount corresponding to one operating frequency that is a high frequency is set to the upper threshold of the load amount corresponding to the other operating frequency that is a low frequency for two operating frequencies that are adjacent to each other. Is set to a smaller value. The frequency switching control unit 21 compares the variable Total_ticks set by the load amount detection unit 20 with an upper limit threshold and a lower limit threshold of the load amount corresponding to the current operation frequency, and changes the operation frequency according to the comparison result. Execute the process for This makes it possible to appropriately control the operating frequency of the processor 1 and prevent overreaction, thereby improving the operating efficiency of the processor 1 and reducing power consumption.

In the above embodiment, the tick counter 1
It has been described that the task executed within a certain period of time and the tick value required in the interrupt processing are obtained by integrating the count value of 0 to specify the load amount of the processor 1, but the present invention is not limited to this. Not something. That is, the load amount detection unit 20 may use an arbitrary method for specifying the load amount of the processor 1 corresponding to the processing executed by the processor 1. For example, data indicating the correspondence between the processing executed by the processor 1 and the load amount of the processor 1 is represented by R
OM2 is stored in advance, and the load amount detection unit 20
The load amount may be specified from the processing executed by the processor 1 by referring to the data stored in M2.

The predetermined time T _{mon, which} is a cycle for monitoring the load of the processor 1, may be changed. For example, an arbitrary time may be set according to the instruction information input by the input unit 4. May be.

In the above embodiment, the processor 1 has been described as being provided with the tick counter 10.
It is not limited to this. That is, as shown in FIG. 11, for example, an RTC (Real Time Clock) 40 capable of counting a tick value is provided outside the processor 1 so as to monitor the load of the processor 1 and a predetermined time T _mon.
May be used for the measurement.

In the above embodiment, the operation program serving as the OS for realizing the operation frequency control system 101 has been described as being stored in the ROM 2 in advance, but the present invention is not limited to this. That is, the operation program may be recorded on a computer-readable recording medium such as an FD, a CD-ROM, a DVD, or an IC memory and distributed. Further, the information is recorded on a disk device or the like of a server device on the Internet, and is stored in a computer functioning as the portable information processing terminal 100.
For example, it may be superimposed on a carrier wave and downloaded.

[0079]

According to the present invention, the operating frequency of the processor can be appropriately controlled.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a portable information processing terminal to which an operating frequency control system according to an embodiment of the present invention is applied.

FIG. 2A is a diagram illustrating an operating frequency data table, and FIG. 2B is a diagram illustrating an operating frequency request management table.

FIG. 3 is a diagram showing a logical configuration of an operating frequency control system.

FIG. 4 is a flowchart illustrating an operating frequency automatic switching process.

FIG. 5 is a flowchart for explaining an operating frequency clock up process.

FIG. 6 is a flowchart for explaining an operating frequency clock down process.

FIG. 7 is a diagram for explaining a problem that occurs when an upper limit threshold and a lower limit threshold of a load amount corresponding to large and small adjacent operating frequencies are matched.

FIG. 8 is a diagram for describing an upper limit threshold and a lower limit threshold of a load amount set in an operating frequency data table.

FIG. 9 is a diagram for explaining the operation of the operating frequency control system to which the settings shown in FIG. 8 are applied.

FIG. 10 is a diagram for explaining an operation of the operating frequency control system to which the settings shown in FIG. 8 are applied.

FIG. 11 is a diagram showing a modification of the portable information processing terminal to which the operating frequency control system according to the embodiment of the present invention is applied.

FIG. 12 is a diagram for explaining a relationship between a processing speed and power consumption and an operating frequency.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processor 2 ROM 3 RAM 4 Input part 5 Display control part 6 Display part 7 Power supply control part 8 Power supply 10 Tick counter 11 Operating frequency data table 12 Operating frequency request management table 20 Load amount detecting part 21 Frequency switching control part 22 Timing detection Unit 23 monitor flag 24 operation mode setting processing unit 30 performance monitor timer 40 RTC 100 portable information processing terminal 101 operating frequency control system

Claims (7)

[Claims] 1. An operating frequency control system for automatically switching an operating frequency of a processor, comprising: an upper limit threshold and a lower limit threshold of a processor load amount associated with an operating frequency settable for the processor. Storage means for storing data in advance; load amount detection means for detecting the load amount of the processor; and referring to table data stored in the storage means, the load amount of the processor detected by the load amount detection means is referred to. By comparing with at least one of the upper threshold and the lower threshold of the processor load corresponding to the operating frequency currently set for the processor,
Frequency control means for executing a process for changing the operating frequency of the processor when determining whether to change the operating frequency of the processor, and when determining to change, the table stored in the storage means The data indicates that the lower limit threshold value of the processor load amount corresponding to one of the higher operating frequencies is two of the operating frequencies that are larger and smaller than the operating frequencies that can be set for the processor.
An operating frequency control system, wherein the operating frequency control system is set to be smaller than an upper limit threshold value of a processor load amount corresponding to the other operating frequency that is a low frequency. 2. The load amount detecting means monitors the load amount of the processor at a predetermined timing, and integrates the monitored load amount every time a predetermined time elapses. The operating frequency control system according to claim 1, wherein whether to change the operating frequency of the processor is determined based on the load amount integrated by the amount detecting unit. 3. A timing detecting means for detecting a switching timing of a task executed by a processor, an execution start timing and an execution end timing of an interrupt process, wherein the load amount detecting means detects the load amount detected by the timing detecting means. The operating frequency control system according to claim 2, wherein the amount of load on the processor is monitored at a timing. 4. The processor according to claim 1, wherein the load of the processor detected by the load detector exceeds an upper limit of a processor load corresponding to an operating frequency currently set for the processor. If it is determined that the operation frequency of the processor is clocked up by one step, the operation that can be set for the processor is performed. 3. A process for clocking down to a highest frequency in which a corresponding upper limit threshold of a load amount exceeds a processor load amount detected by the load amount detection means. 4. The operating frequency control system according to 3. 5. A portable information processing terminal comprising: a processor capable of switching an operating frequency; and a storage circuit for storing an operation program and data executed by the processor, wherein the data stored in the storage circuit is And table data indicating an upper limit threshold and a lower limit threshold of a processor load amount associated with an operating frequency that can be set for the processor, wherein the processor executes an operation program stored in the storage circuit. By referring to the load amount detecting means for detecting the load amount and the table data stored in the storage circuit, the load amount detected by the load amount detecting means corresponds to the currently set operating frequency. By comparing the operating frequency with at least one of the upper threshold value and the lower threshold value of the processor load amount, the operating frequency is determined. Determine whether or not to change, and if it is determined to change, comprising frequency control means for performing a process for changing the operating frequency, the table data stored in the storage circuit, the processor The lower limit threshold value of the processor load amount corresponding to one of the higher operating frequencies is set to the processor load corresponding to the other lower operating frequency of the two operating frequencies that are larger and smaller than each other among the operating frequencies that can be set. A portable information processing terminal, wherein the portable information processing terminal is set to be smaller than an upper limit threshold of the amount. 6. An operating frequency control method for automatically switching an operating frequency of a processor, comprising: table data indicating an upper limit threshold and a lower limit threshold of a processor load corresponding to an operating frequency that can be set for the processor. The lower limit threshold value of the processor load amount corresponding to one of the operating frequencies that is higher in the two operating frequencies that are larger and smaller than the operating frequency that can be set for the processor is the other operating frequency that is the lower frequency Is stored in advance in a predetermined storage circuit, and the processor executes an operation program to detect the load amount and store the table data in the storage circuit. Refers to the table data that has been set, and compares the detected load amount with the currently set operating frequency. Determining whether to change the operating frequency by comparing with at least one of the upper threshold value and the lower threshold value of the processor load amount, and executing a process for changing the operating frequency when determining to change the operating frequency; Operating frequency control method characterized by the above-mentioned. 7. A computer, comprising: storage means for storing in advance table data indicating an upper limit threshold and a lower limit threshold of a processor load in association with an operating frequency which can be set for the processor; and detecting a load of the processor. A load amount detection unit, and a processor corresponding to an operating frequency currently set for the processor, by referring to table data stored in the storage unit and determining a load amount of the processor detected by the load amount detection unit. By comparing with at least one of the upper threshold and the lower threshold of the load amount,
It is determined whether or not to change the operating frequency of the processor, and when it is determined that the operating frequency is to be changed, it is made to function as frequency control means for executing a process for changing the operating frequency of the processor, and a table stored in the storage means The data indicates that the lower limit threshold value of the processor load amount corresponding to one of the higher operating frequencies is two of the operating frequencies that are larger and smaller than the operating frequencies that can be set for the processor.
A program set to be smaller than an upper limit threshold value of a processor load amount corresponding to the other operation frequency that is a low frequency.