JP6951019B2 - Counter device, time calculation device, information processing device, control method, time calculation method and program - Google Patents

Description

The present invention includes a counter unit, time calculation unit, the information processing apparatus, control method, a time calculation method and a program.

The information processing device generates a system timer based on a counter operated by a CPU clock. Time information is managed by one system timer for the system time shared between the operating systems operating in this information processing device and tasks. The system timer is updated according to the time acquired from the NTP server. When the system timer is updated, the time events of the system may be out of order, such as the execution order of tasks being reversed or the processing progressing suddenly, depending on the timing of timer interrupts and time references.

In order to avoid such an event, a highly accurate oscillator is installed in the information processing device, time information is acquired from the NTP server only when the system is started, and the system time is used after the system is started. There is something to manage. In the case of this method, since the time information is continuously acquired from the NTP server and the system timer is not updated, the time event on the system is not reversed, but the NTP becomes longer after the system is started. The difference between the server time and the system time gradually increases.

As a related technique, Patent Document 1 discloses a printer that manages the system time based on a crystal oscillator included in the own machine. This printer outputs a reference clock signal once every time the crystal oscillator vibrates a predetermined number of times, and when the reference clock signal is output a predetermined number of times, the time is advanced by one second to manage the system time. When the printer acquires the time from the NTP server, it compares the acquired time with the time of its own machine, calculates the difference between the two, and calculates the correction amount corresponding to the difference. Then, when the crystal oscillator vibrates (predetermined number of times + correction amount), the operation is changed so as to output one reference clock signal, thereby adjusting the system time.

Further, in Patent Document 2, the time of the NTP client terminal device is updated with the time information acquired from the NTP server device only when the communication between the NTP server device and the NTP client terminal device is performed in the minimum time. Discloses a method of achieving stable time synchronization between an NTP server device and an NTP client terminal device regardless of fluctuations in communication time between a server and a client.

Japanese Unexamined Patent Publication No. 2003-207586 Japanese Unexamined Patent Publication No. 2018-098711

There is a demand for a counter that operates based on a CPU clock and counts at a specific cycle while maintaining a constant accuracy even if there is no highly accurate oscillator.

Therefore the invention aims at providing a counter apparatus to solve the above problems, time calculation device, an information processing apparatus, control method, a time calculation method and program.

According to one aspect of the present invention, the counter device multiplies the count value of the CPU clock counter that operates in synchronization with the clock of the CPU by a conversion coefficient to obtain the first count value by the first counter that operates in a specific cycle. The first counter generation unit to be calculated, the second counter conversion unit that converts the time information into the second count value by the second counter operating in the specific cycle, and the first count value and the second count value. When the difference becomes equal to or larger than a predetermined threshold value, the difference becomes smaller than the present value, and the fluctuation of the first count value calculated by the first counter at a predetermined time due to the adjustment of the conversion coefficient is within a predetermined range. A conversion coefficient calculation unit for adjusting the conversion coefficient is provided so as to be inside.

Further, according to another aspect of the present invention, time calculation apparatus includes the above counter device, and calendar time conversion unit for converting the first count value in calendar time, the.

Further, according to another aspect of the present invention, the information processing device includes the above-mentioned counter device and an NTP time acquisition unit that acquires time information from an NTP server.

Further, according to another aspect of the present invention, it is a control method of a first counter that operates based on a CPU clock counter that operates in synchronization with the clock of the CPU, and is converted into a count value of the CPU clock counter. To calculate the first count value by the first counter operating in a specific cycle by multiplying by, and to convert the time information into a second count value by the second counter operating in the specific cycle. When the difference between the first count value and the second count value becomes equal to or greater than a predetermined threshold value, the difference becomes smaller than the present value, and the first count value calculated by the first counter at a predetermined time. This is a control method including a step of adjusting the conversion coefficient so that the fluctuation due to the adjustment of the conversion coefficient is within a predetermined range.

Further, according to another aspect of the present invention, it is a calendar time calculation method in which the first counter is controlled by the above control method and the calendar time is calculated based on the first count value.

Further, according to another aspect of the present invention, the program operates the computer in a specific cycle by multiplying the count value of the CPU clock counter that operates in synchronization with the CPU clock by a conversion factor. The means for calculating the first count value according to the above, the means for converting the time information into the second count value by the second counter operating in the specific cycle, the difference between the first count value and the second count value is predetermined. When it becomes equal to or more than the threshold value, the difference becomes smaller than the present, and the fluctuation of the first count value calculated by the first counter at a predetermined time due to the adjustment of the conversion coefficient is within a predetermined range. To function as a means for adjusting the conversion coefficient.

According to the present invention, it is possible to obtain a counter that keeps counting at a predetermined target cycle with high accuracy. Further, by using this counter, the accuracy of the system time of the information processing apparatus can be maintained.

It is a figure which shows an example of the information processing apparatus which concerns on 1st Embodiment of this invention. It is the first figure explaining the control of the 1μ second counter by the 1st Embodiment of this invention. FIG. 2 is a second diagram illustrating control of a 1 μs counter according to the first embodiment of the present invention. It is a flowchart which shows an example of the control of 1μ sec counter by 1st Embodiment of this invention. It is a figure which shows an example of the information processing apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows an example of the control of the 1μ second counter by the 2nd Embodiment of this invention. It is a figure which shows the minimum structure of the counter device in one Embodiment of this invention. It is a figure which shows an example of the hardware composition of the information processing apparatus in one Embodiment of this invention.

Hereinafter, a method for controlling a 1 μs counter according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of an information processing device according to the first embodiment of the present invention.
As shown in the figure, the information processing apparatus 301 includes a CPU clock counter 10, a 1 μs counter generation unit 200, a calendar time conversion unit 201, an NTP time acquisition unit 202, an NTP time acquisition unit 202, and a 1 μs counter conversion unit. It includes 203, a count value comparison unit 204, a conversion coefficient calculation unit 205, and a set time acquisition unit 206.

The CPU clock counter 10 operates in synchronization with a CPU (not shown) and outputs a count value at the clock cycle of the CPU. The CPU clock counter 10 is generally provided inside the CPU chip as a function of the CPU.

The 1 μs counter generation unit 200 multiplies the count value output by the CPU clock counter 10 by a preset conversion coefficient 15 to generate the count value 11 in a 1 μs cycle. In the present embodiment, the 1 μs counter is realized by the operation of the 1 μs counter generation unit 200, and this 1 μs counter is used as the system clock which is the basis of the time calculation. Since the 1 μs counter counts 1,000,000 times per second, the conversion coefficient 15 is obtained by dividing 1,000,000 by the count value per second by the CPU clock counter 10. That is, the 1 μs counter generation unit 200 generates a count value 11 which is increased by 1 each time the count value output by the CPU clock counter 10 increases by the value of the conversion coefficient 15. For example, the count value 11 is a value expressing the elapsed time from the time the system is started to the present time in units of microseconds.

The calendar time conversion unit 201 converts the count value in 1 μs units calculated by the 1 μs counter generation unit 200 into the calendar time.
The NTP time acquisition unit 202 acquires time information (calendar time 16) from the NTP server 300.

The 1 μs counter conversion unit 203 converts the calendar time 16 acquired by the NTP time acquisition unit 202 into a count value by a counter operating in a 1 μs cycle. The count value in 1 μs units converted by the 1 μs counter conversion unit 203 is used for the purpose of being referred to in order to maintain the accuracy of the 1 μs counter realized by the 1 μs counter generation unit 200. The calendar time 16 acquired from the NTP server 300 cannot be compared with the count value 11 generated by the 1 μs counter generation unit 200. Therefore, the 1 μs counter conversion unit 203 converts the time information acquired by the NTP time acquisition unit 202 into a count value 12 which is counted up every 1 μs. For example, the count value 12 indicates a value expressing the elapsed time from a specific date and time to the present time in μsecond units, and mutual conversion between the count value 12 and the calendar time is possible. Further, since the count value 12 and the count value 11 are both values indicating the elapsed time from that time with reference to a certain time, they can be compared.

The count value comparison unit 204 obtains the difference between the count value 11 generated by the 1 μs counter generation unit 200 and the count value 12 converted by the 1 μs counter conversion unit 203. If the count value 11 generated by the 1 μs counter generation unit 200 and the count value 12 converted by the 1 μs counter conversion unit 203 are both accurately counted up by 1 every 1 μs, the count value 11 and the count value 12 The difference is constant. However, since the clock period of the CPU clock counter 10 fluctuates, the difference between the count value 11 calculated based on the operation of the CPU clock counter 10 and the count value 12 actually fluctuates. If it is detected that the count value 11 gradually becomes larger than the count value 12, the 1 μs counter generated by the 1 μs counter generator 200 counts at intervals shorter than the actual 1 μs. In this case, the time information calculated by the calendar time conversion unit 201 tends to advance compared to the actual time. On the contrary, if a tendency that the count value 11 gradually becomes smaller than the count value 12 is detected as compared with the time when the system is started, the 1 μs counter is counting at intervals longer than the actual 1 μs, and the calendar. The time information calculated by the time conversion unit 201 tends to be delayed compared to the actual time. The conversion coefficient calculation unit 205, which will be described next, adjusts the conversion coefficient 15 so as to correct the delay or advance of the count value 11.

The conversion coefficient calculation unit 205 compares the difference value 13 obtained from the count value comparison unit 204 at the time of system startup with the difference value 14 obtained from the count value comparison unit 204 after a certain period of time has elapsed from the system startup, and the difference is If it exceeds the permissible range (correction instruction determination time 17), the value of the conversion coefficient 15 is updated so that the difference becomes small.

The set time acquisition unit 206 receives the setting of the system time of the information processing device 301 from the user. The system time may be the actual current time provided by the NTP server 300, or may be any time in the past or future. The system time of the information processing device 301 is set to the date and time received by the set time acquisition unit 206, and the system time after the setting is set by the count value 11 generated by the 1 μs counter generation unit 200 and the calendar time conversion unit 201. It is managed accurately.

In general, the accuracy of the clock cycle of the CPU clock counter 10 used in a server device or the like is often not sufficient, and may fluctuate due to, for example, heat generation of the information processing device 301 itself or the influence of the surrounding environment. As described above, the operating accuracy of the CPU clock counter 10 is the accuracy of the count value 11 generated by the 1 μs counter generation unit 200 as it is, and the accuracy of the system time converted by the calendar time conversion unit 201. Therefore, if the clock cycle of the CPU clock counter 10 fluctuates, the system time of the information processing apparatus 301 may also be out of order, which may affect the execution of tasks. On the other hand, in the present embodiment, the time information is periodically acquired from the NTP server 300 during the operation of the information processing apparatus 301 without using a highly accurate oscillator or the like, and the conversion coefficient 15 is set based on the time information. Adjust the value. Then, the time obtained by multiplying the clock period of the CPU clock counter 10 by the conversion coefficient 15 is controlled so as to maintain 1 μsec with an accuracy of a certain level or more.
Next, a method of adjusting the conversion coefficient 15 will be described with reference to FIGS. 2 and 3.

FIG. 2 is a first diagram illustrating control of a counter according to the first embodiment of the present invention.
FIG. 3 is a second diagram illustrating control of the counter according to the first embodiment of the present invention.
Immediately after the system is started, the time T0 of the first measurement point is set. First, the difference between the count value 12 (Tb0) converted by the 1 μs counter conversion unit 203 to the time T0 by the count value comparison unit 204 and the count value 11 (Ta0) generated by the 1 μs counter generation unit 200 at the time T0. The value 13 (Tc0) is calculated by Ta0-Tb0. This difference value 13 (Tc0) is used as a reference value for time correction.

After that, when a certain time elapses from the time Tc0 and the next measurement point (time Tx) is reached, the count value comparison unit 204 determines the difference value 14 between the count value 11 (Tax) and the count value 12 (Tbx) at the time Tx. (Difference value Tcx) is calculated by Tax-Tbx. Then, the conversion coefficient calculation unit 205 compares the difference value 13 (Tc0) with the difference value 14 (Tcx). If the difference between the difference value 13 (Tc0) and the difference value 14 (Tcx) is within the range of the value (Ts) indicated by the correction instruction determination time 17 (setting in the third line of FIG. 3), the 1 μs counter generator 200 It is considered that the count cycle of is maintained at about 1 μsec, and the conversion coefficient calculation unit 205 does not correct the conversion coefficient 15.

When the difference value 14 (Tcx) is smaller than the difference value 13 (Tc0) and the difference is larger than the time difference (Ts) indicated by the correction instruction determination time 17 (setting in the first line of FIG. 3), 1 μsec. It is determined that the count value 11 generated by the counter generation unit 200 is delayed, and the conversion coefficient calculation unit 205 newly obtains the conversion coefficient 15 so that the count value 11 generated by the counter generation unit 200 advances for 1 μs. That is, the conversion coefficient calculation unit 205 updates the conversion coefficient 15 to a value larger than the value set at the time of system startup.

Further, when the difference value 14 (Tcx) is larger than the difference value 13 (Tc0) and the difference is larger than the time difference (Ts) indicated by the correction instruction determination time 17 (setting in the second line of FIG. 3). Determining that the count value 11 is advanced, the conversion coefficient calculation unit 205 newly obtains the conversion coefficient 15 so that the count value 11 generated by the 1 μs counter generation unit 200 is delayed. That is, the conversion coefficient calculation unit 205 updates the conversion coefficient 15 to a value smaller than the value set at the time of system startup.

In this way, the accuracy of the count value 11 calculated by the 1 μs counter generation unit 200 can be maintained. Further, the system time calculated by the calendar time conversion unit 201 by converting the count value 11 is set so that the difference from the calendar time 16 acquired from the NTP server 300 is within a certain time by the correction of the conversion coefficient 15 described above. It will be corrected. That is, the accuracy of the system time can be maintained by periodically updating the conversion coefficient 15 and correcting the time by the converted conversion coefficient 15 after the update.

Next, a method of controlling the 1 μs counter in the first embodiment will be described.
FIG. 4 is a flowchart showing an example of control of a 1 μs counter (count value 11) according to the first embodiment of the present invention.
_{As a premise, the initial value K 0} of the conversion coefficient 15 that converts the clock period of the CPU clock counter 10 to 1 μsec is calculated in advance based on the design value of the CPU clock counter 10, and the 1 μsec counter generator 200 uses this. It is assumed that K ₀ is multiplied by the count value of the CPU clock counter 10 and output to the calendar time conversion unit 201.

First, the user activates the information processing device 301. The count value comparison unit 204 calculates a reference difference value (Tc0) when the system is started (step S11). Specifically, the NTP time acquisition unit 202 acquires the calendar time 16 from the NTP server 300. The 1 μs counter conversion unit 203 converts the calendar time 16 into a count value 12 in 1 μs units. For example, the count value 12 indicates a count value when the elapsed time from a specific date and time to the time indicated by the calendar time 16 is counted in units of 1 μsecond. The 1 μs counter conversion unit 203 outputs the count value 12 to the count value comparison unit 204.

On the other hand, the 1 μs counter generation unit 200 acquires the count value from the CPU clock counter 10 _{and multiplies the initial value K 0} of the conversion coefficient 15 to generate the count value 11. The 1 μs counter generation unit 200 outputs the count value 11 to the count value comparison unit 204.
The count value comparison unit 204 calculates the difference value (Tc0) between the two by subtracting the initial value (Tb0) of the count value 12 from the initial value (Ta0) of the count value 11. The count value comparison unit 204 stores a reference difference value (Tc0).

In parallel with these processes, the 1 μs counter generation unit 200 outputs the count value 11 to the calendar time conversion unit 201. Further, the user inputs the time set as the system time of the information processing device 301 to the information processing device 301. The set time input by the user may be any date and time, or may be information instructing the system time of the information processing apparatus 301 to be adjusted to the current time acquired from the NTP server 300. The set time acquisition unit 206 acquires the set time input by the user and outputs it to the calendar time conversion unit 201. The calendar time conversion unit 201 converts the latest count value 11 into a set time specified by the user and sets the system time.

Further, the NTP time acquisition unit 202 acquires the calendar time 16 from the NTP server 300 at predetermined time intervals, and the 1 μs counter conversion unit 203 calculates the count value 12 each time. Further, the 1 μs counter generation unit 200 calculates the count value 11 every 1 μs based on the operation of the CPU clock counter 10, and the calendar time conversion unit 201 converts the count value 11 into the system time based on the count value 11. Continue to do. Further, the count value comparison unit 204 waits for the arrival of the measurement point while acquiring the count value 11 and the count value 12 from the 1 μs counter generation unit 200 and the 1 μs counter conversion unit 203, respectively (step S12).

When the measurement point arrives (step S12; Yes), the count value comparison unit 204 subtracts the count value 12 (Tbx) from the latest count value 11 (Tax) to calculate the difference value (Tcx) between the two. Then, the count value comparison unit 204 outputs the latest difference value (Tcx) and the reference difference value (Tc0) to the conversion coefficient calculation unit 205.

The conversion coefficient calculation unit 205 compares the latest difference value (Tcx) with the reference difference value (Tc0), and calculates the magnitude relationship between the two and the absolute value of the difference. The conversion coefficient calculation unit 205 adjusts the value of the conversion coefficient 15 based on the calculated magnitude relationship and the absolute value of the difference. When the difference between Tc0 and Tcx is within a predetermined range (the difference is the correction instruction determination time 17 or less) (step S13; Yes), the conversion coefficient calculation unit 205 does not update the conversion coefficient 15 (step S14). The 1 μs counter generation unit 200 outputs the count value 11 generated by multiplying the count value output by the CPU clock counter 10 by the same conversion coefficient 15 as before to the calendar time conversion unit 201.

When the difference between Tc0 and Tcx is the correction instruction determination time 17 or more (step S13; No), the conversion coefficient calculation unit 205 updates the conversion coefficient 15 (step S15). More specifically, as described with reference to FIG. 3, if Tcx> Tc0, the conversion coefficient 15 is decreased, and if Tcx <Tc0, the conversion coefficient 15 is increased. For example, when the value of the conversion coefficient 15 set at the time of system startup is set to K ₀ , the conversion coefficient Kn for delaying by t seconds in 1 hour is calculated by _{Kn = (1-t / 3600) × K 0.} The value Kn of the conversion coefficient 15 for advancing by t seconds in one hour is calculated by _{Kn = (1 + t / 3600) × K 0.}
The conversion coefficient calculation unit 205 outputs the updated conversion coefficient 15 to the 1 μs counter generation unit 200. The 1 μs counter generation unit 200 outputs the count value 11 generated by multiplying the count value output by the CPU clock counter 10 by the new conversion coefficient 15 after the update to the calendar time conversion unit 201.

Next, the calendar time conversion unit 201 converts the count value 11 into the system time (step S16). Next, it is determined whether or not to stop the system of the information processing device 301 (step S17). If it does not stop (step S17; No), the processes after step S12 are repeated. As a result, if the count value 11 is delayed or preceded too much during system startup, the value of the conversion coefficient 15 is adjusted, and the count value 11 is output with a constant accuracy every 1 μs. Further, the system time of the information processing apparatus 301 is also maintained at a constant accuracy.

When the system is stopped (step S17; Yes), a series of processes is stopped. Then, when the system is started again, the process from step S11 is executed.

According to this embodiment, it is possible to generate a counter based on a high-precision CPU clock without requiring dedicated hardware such as a high-precision oscillator. Further, for example, when a deviation from the time provided by the NTP server 300 is detected, the NTP server 300 is gradually adjusted by adjusting the conversion coefficient 15 instead of suddenly synchronizing with the time of the NTP server 300. Since the time can be approached, the execution order between tasks is not reversed. Therefore, it is possible to synchronize with the time of the NTP server 300 without affecting the operation of the system during system operation.

Since the calendar time 16 is acquired between the NTP server 300 and the NTP time acquisition unit 202 using the Internet, a time lag such as a delay due to communication can be considered, but in the present embodiment, the time difference from the NTP server 300 is considered. It suffices if the correction can be made for about 1 second at all times so that the time difference does not spread, and the time difference from the NTP server 300 may exist, for example, about several hundred milliseconds.

<Second embodiment>
Hereinafter, a method of controlling the 1 μs counter according to the second embodiment of the present invention will be described with reference to FIGS. 5 to 6.
In the first embodiment, it is assumed that communication with the NTP server 300 is possible. However, there may be a situation where the latest time information (calendar time 16) cannot be obtained from the NTP server 300 due to a communication failure or the like. In this case, the 1 μs counter conversion unit 203 cannot generate the count value 12 based on the time information acquired from the NTP server 300, and cannot correct the count value 11 by the method of the first embodiment. Then, the value of the conversion coefficient 15 referred to by the 1 μs counter generation unit 200 is fixed until the communication line becomes normal. At this time, the value of the count value 11 is completely proportional to the number of clocks of the CPU clock counter 10, but the clock cycle of the CPU clock counter 10 fluctuates, and the clock cycle also varies from device to device. , The accuracy of the count value 11 generated by using it may be low. In order to avoid this, the information processing apparatus 301a according to the second embodiment measures the count value and the count value 12 of the CPU clock counter 10 for a long time in advance when the communication line is normal, and the clock period of the CPU clock counter 10 The conversion coefficient 15a is calculated based on the averaged value of. Then, while the time information cannot be acquired from the NTP server 300, the conversion coefficient 15a set in consideration of the fluctuation of the CPU clock counter 10 is used, and the accuracy of the 1 μs counter is kept above a certain level.

FIG. 5 is a diagram showing an example of an information processing device according to the second embodiment of the present invention.
In addition to the configuration of the first embodiment, the information processing apparatus 301a includes a pre-conversion coefficient calculation unit 400, a time synchronization abnormality detection unit 401, a conversion coefficient switching unit 402, and a conversion coefficient holding unit 403. Among the configurations according to the second embodiment, the same configurations as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The pre-conversion coefficient calculation unit 400 outputs a count value output by the CPU clock counter 10 from the time the system is started until a predetermined time elapses, and a 1 μs counter conversion unit 203 outputs the count value from the time the system is started until the predetermined time elapses. Based on the count value 12, the conversion coefficient 15a used in the situation where the time information cannot be acquired from the NTP server 300 is calculated.

The time synchronization abnormality detection unit 401 detects that the NTP time acquisition unit 202 cannot normally acquire the time information from the NTP server 300 due to an abnormality in the line or the like.
The conversion coefficient switching unit 402 switches from the conversion coefficient 15 used during normal operation to the conversion coefficient 15a when the time synchronization abnormality detection unit 401 detects an abnormality, and when communication returns to normal, the original conversion coefficient 15 Performs switching control to return to.
The conversion coefficient holding unit 403 holds the value of the conversion coefficient 15a calculated by the pre-conversion coefficient calculation unit 400.

Next, a method of calculating the conversion coefficient 15a by the pre-conversion coefficient calculation unit 400 will be described.
Let T0 be the time when the system starts up. The pre-conversion coefficient calculation unit 400 stores the count value Td0 output by the CPU clock counter 10 at time T0 and the value Tn0 of the count value 12 output by the 1 μs counter conversion unit 203 at time T0. Further, the pre-conversion coefficient calculation unit 400 waits for a long time (T1 hour) so that the fluctuation of the clock of the CPU clock counter 10 can be averaged. When the T1 time elapses, the pre-conversion coefficient calculation unit 400 stores the count value Td1 output by the CPU clock counter 10 after T1 hour and the value Tn1 of the count value 12 output by the 1 μs counter conversion unit 203 after T1 hour. .. Then, the pre-conversion coefficient calculation unit 400 calculates the value Ka of the conversion coefficient 15a, which is the average of the clock fluctuation of the CPU clock counter 10, by the following equation (1).
Ka = (Tn1-Tn0) / (Td1-Td0) ... (1)
The pre-conversion coefficient calculation unit 400 outputs the calculated value Ka to the conversion coefficient holding unit 403. The conversion coefficient holding unit 403 stores the value Ka.

Next, a method of controlling the 1 μs counter (count value 11) in the second embodiment will be described.
FIG. 6 is a flowchart showing an example of control of a 1 μs counter according to the second embodiment of the present invention.
It will be described that communication with the NTP server 300 is possible until T1 time elapses after the system is started.
First, the system of the information processing device 301a is started by the user's operation (step S21). The pre-conversion coefficient calculation unit 400 stores the count value Td0 of the CPU clock counter 10 immediately after the system is started (time T0) and the value Tn0 of the count value 12 of the 1 μs counter conversion unit 203.
Next, the time synchronization abnormality detection unit 401 determines whether or not the communication with the NTP server 300 is normal (step S22). When the communication is normal (step S22; Yes), the conversion coefficient switching unit 402 sets the conversion coefficient 15 as the conversion coefficient used by the 1 μs counter generation unit 200 (step S23). Then, the conversion coefficient calculation unit 205 updates the conversion coefficient 15 or the like by the process described with reference to FIG. 4, and maintains the accuracy of the count value 11 generated by the 1 μs counter generation unit 200 (step S24).

Further, the pre-conversion coefficient calculation unit 400 determines whether or not the time T1 has elapsed and the conversion coefficient 15a has not been calculated after the system is started (step S25). When these conditions are satisfied (step S25; Yes), the pre-conversion coefficient calculation unit 400 sets the count value Td1 of the CPU clock counter 10 after the lapse of time T1 and the value Tn1 of the count value 12 of the 1 μs counter conversion unit 203. Using the previously stored values Td0 and Tn1, the value Ka of the conversion coefficient 15a is calculated by the above equation (1) (step S26). The conversion coefficient holding unit 403 holds the value Ka calculated by the pre-conversion coefficient calculation unit 400. If the time T1 has not elapsed or the conversion coefficient 15a has already been calculated (step S25; No), the conversion coefficient 15a is not calculated and the process proceeds to step S28.

Next, the calendar time conversion unit 201 converts the count value 11 into the calendar time (step S28). When the system of the information processing apparatus 301 is stopped (step S28; Yes), the processing of this flowchart is terminated. When the system is not stopped (step S28; No), the processes after step S22 are repeated. For example, when the time synchronization abnormality detection unit 401 detects a communication abnormality in step S22, the conversion coefficient switching unit 402 holds the conversion coefficient used by the 1 μs counter generation unit 200 from the conversion coefficient 15 to the conversion coefficient holding unit 403. The conversion coefficient is switched to 15a (step S27). The conversion coefficient 15a is a coefficient that converts the count value of the CPU clock counter 10 that averages the fluctuation of the clock cycle into the count value output by the counter that operates in a cycle of 1 μsec based on the actual time information. While the communication abnormality is detected, the 1 μs counter generation unit 200 outputs the count value 11 generated by multiplying the count value output by the CPU clock counter 10 by the conversion coefficient 15a to the calendar time conversion unit 201. The calendar time conversion unit 201 converts the count value 11 into the calendar time (step S28).

Then, when the communication with the NTP server 300 is restored, the conversion coefficient switching unit 402 switches the conversion coefficient used by the 1 μs counter generation unit 200 from the conversion coefficient 15a to the conversion coefficient 15. Then, the same control as in the first embodiment is performed.

According to the present embodiment, assuming a state in which communication with the NTP server 300 cannot be performed due to some failure, a conversion coefficient 15a obtained by averaging the fluctuations of the CPU clock counter 10 is obtained in advance, and when a line failure occurs, the conversion coefficient is obtained. 15a can be used. As a result, in addition to the effect of the first embodiment, the count value 11 can be generated while maintaining a certain degree of accuracy even in a situation where the time information cannot be acquired from the NTP server 300. Therefore, it is possible to configure the system timer with an accuracy close to that of the dedicated hardware without requiring a dedicated hardware such as an oscillator for time correction.
In step S25, once the conversion coefficient 15a is calculated, it is not updated. For example, every time the time T1 elapses, the count value of the CPU clock counter 10 at the start and end of the latest time T1. And the conversion coefficient 15a may be calculated based on the count value 12.

Further, in recent computing environments, there are an increasing number of situations in which a plurality of information processing devices are connected to a network and a plurality of systems are required to be operated in cooperation with each other. In such a system, it is necessary to match the system time of each information processing device, but if the time is changed momentarily based on the time information acquired from the NTP server during system operation, the time between operating systems and tasks The relationship can be reversed. On the other hand, according to the 1 μs counter (1 μs counter generation unit 200) provided by the first embodiment and the second embodiment, each information processing device autonomously operates based on the time information from the NTP server 300. By gradually advancing or delaying the system time, it is possible to adjust to the time of the NTP server 300. At that time, the system time can be adjusted so that the time relationship between the tasks in the information processing apparatus 301 does not conflict with each other by time synchronization.

FIG. 7 is a diagram showing a minimum configuration of a counter device according to an embodiment of the present invention.
As shown in FIG. 7, the counter device 100 includes at least a first counter generation unit 101, a second counter conversion unit 102, and a conversion coefficient calculation unit 103.
The first counter generation unit 101 multiplies the count value of the CPU clock counter that operates in synchronization with the CPU clock by a conversion coefficient to calculate the first count value by the first counter that operates in a specific cycle.
The second counter conversion unit 102 converts the time information into a second count value by the second counter that operates in the specific cycle.
The conversion coefficient calculation unit 103 adjusts the conversion coefficient so that the time-dependent fluctuation of the difference between the first count value and the second count value is within a predetermined range.
Compared with the configurations of the first embodiment and the second embodiment, the first counter generation unit 101 corresponds to the 1 μs counter generation unit 200, and the second counter conversion unit 102 corresponds to the 1 μs counter conversion unit 203. , The conversion coefficient calculation unit 103 corresponds to the conversion coefficient calculation unit 205.
In one embodiment, the difference value obtained by subtracting the count value of the second counter conversion unit 102 from the count value of the first counter generation unit 101 is the difference value Tc0 at the time of system startup and after a predetermined time has elapsed after system startup. If the difference from the difference value Tcx of is not within a predetermined range, the conversion coefficient calculation unit 103 determines that the first counter generation unit 101 is advancing if the difference is positive, and generates the first counter. The conversion coefficient is calculated so as to delay the count of the unit 101. If the difference is negative, it is determined that the first counter generation unit 101 is delayed, and the conversion coefficient is calculated so as to advance the count of the first counter generation unit 101.

FIG. 8 is a diagram showing an example of the hardware configuration of the information processing apparatus according to the embodiment of the present invention.
The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The information processing devices 301 and 301a described above are mounted on the computer 900. Then, the above-mentioned 1 μs counter generation unit 200, calendar time conversion unit 201, NTP time acquisition unit 202, NTP time acquisition unit 202, 1 μs counter conversion unit 203, count value comparison unit 204, conversion coefficient calculation unit 205, set time. Each function of the acquisition unit 206, the pre-conversion coefficient calculation unit 400, the time synchronization abnormality detection unit 401, the conversion coefficient switching unit 402, and the conversion coefficient holding unit 403 is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, expands it to the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 secures a storage area in the main storage device 902 according to the program. Further, the CPU 901 secures a storage area for storing the data being processed in the auxiliary storage device 903 according to the program.

In at least one embodiment, the auxiliary storage device 903 is an example of a non-temporary tangible medium. Other examples of non-temporary tangible media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc., which are connected via the input / output interface 904. When this program is distributed to the computer 900 via a communication line, the distributed computer 900 may expand the program to the main storage device 902 and execute the above processing. Further, the program may be for realizing a part of the above-mentioned functions. Further, the program may be a so-called difference file (difference program) that realizes the above-mentioned function in combination with another program already stored in the auxiliary storage device 903.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present invention. Further, the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the embodiment, the period of the counter is set to 1 μsec, but other periods may be used.

10 ... CPU clock counter 200 ... 1 μs counter generation unit 201 ... Calendar time conversion unit 202 ... NTP time acquisition unit 203 ... 1 μs counter conversion unit 204 ... Count value comparison unit 205・ ・ ・ Conversion coefficient calculation unit 206 ・ ・ ・ Set time acquisition unit 300 ・ ・ ・ NTP server 301, 301a ・ ・ ・ Information processing device 400 ・ ・ ・ Pre-conversion coefficient calculation unit 401 ・ ・ ・ Time synchronization abnormality detection unit 402 ・・ ・ Conversion coefficient switching unit 403 ・ ・ ・ Conversion coefficient holding unit

Claims (10)

A first counter generator that calculates the first count value by the first counter that operates in a specific cycle by multiplying the count value of the CPU clock counter that operates in synchronization with the CPU clock by a conversion coefficient.
A second counter conversion unit that converts time information into a second count value by a second counter that operates in the specific cycle.
When the difference between the first count value and the second count value becomes equal to or greater than a predetermined threshold value, the difference becomes smaller than the present value, and the first count value calculated by the first counter at a predetermined time. A conversion coefficient calculation unit that adjusts the conversion coefficient so that the fluctuation due to the adjustment of the conversion coefficient is within a predetermined range.
A counter device comprising. The conversion coefficient calculation unit updates the conversion coefficient when the subsequent difference deviates from the initial difference value by a predetermined threshold value or more based on the initial difference value which is the difference at a predetermined timing.
The counter device according to claim 1. When the difference deviates from the initial difference value by a predetermined threshold value or more and the difference is smaller than the initial difference value.
The conversion coefficient calculation unit updates the value of the conversion coefficient to a larger value.
The counter device according to claim 2. When the difference deviates from the initial difference value by a predetermined threshold value or more and the difference is larger than the initial difference value.
The conversion coefficient calculation unit updates the value of the conversion coefficient to a smaller value.
The counter device according to any one of claims 2 to 3. When the time information is acquired from an external device, a failure detection unit that detects a failure in the acquisition of the time information, and a failure detection unit.
When the failure detection unit detects a failure, the second conversion coefficient to be multiplied by the count value of the CPU clock counter is measured at a plurality of times while the failure is not detected, and the count value of the CPU clock counter and the said. Pre-conversion coefficient calculation unit that calculates based on the second count value,
The counter device according to any one of claims 1 to 4, further comprising. The counter device according to any one of claims 1 to 5.
A calendar time conversion unit that converts the first count value into a calendar time,
Time calculating device when Ru equipped with. The counter device according to any one of claims 1 to 5.
The NTP time acquisition unit that acquires time information from the NTP server,
Information processing device equipped with. It is a control method of a first counter that operates based on a CPU clock counter that operates in synchronization with the CPU clock.
A step of multiplying the count value of the CPU clock counter by a conversion coefficient to calculate a first count value by the first counter that operates in a specific cycle.
A step of converting time information into a second count value by a second counter operating in the specific cycle, and
When the difference between the first count value and the second count value becomes equal to or greater than a predetermined threshold value, the difference becomes smaller than the present value, and the first count value calculated by the first counter at a predetermined time. The step of adjusting the conversion coefficient and the step of adjusting the conversion coefficient so that the fluctuation due to the adjustment of the conversion coefficient is within a predetermined range.
Control method having. The first counter is controlled by the control method according to claim 8.
The calendar time is calculated based on the first count value.
How to calculate the time. Computer,
A means for calculating the first count value by the first counter that operates in a specific cycle by multiplying the count value of the CPU clock counter that operates in synchronization with the CPU clock by a conversion coefficient.
A means for converting time information into a second count value by a second counter operating in the specific cycle.
When the difference between the first count value and the second count value becomes equal to or greater than a predetermined threshold value, the difference becomes smaller than the present value, and the first count value calculated by the first counter at a predetermined time. A means for adjusting the conversion coefficient so that the fluctuation due to the adjustment of the conversion coefficient is within a predetermined range.
A program to function as.

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