Power control apparatus, electronic computer, and power control method

1. A power control apparatus comprising

a processor configured to:

collect first information related to operation of a performing unit configured to perform data processing and second information related to operation of a bus configured to transfer data;

determine an operating frequency and an operating voltage for the performing unit, based on the first information and the second information;

estimate based on the first information and the second information, a first period elapsing until the performing unit suspends data processing that is being performed and a second period elapsing until the bus suspends data transmission that is being conducted;

derive a discriminant that obtains a difference of total power consumption and power consumption pre-switching, the total power consumption being power consumed in a case of switching the operation of the performing unit based on the determined operating frequency and operating voltage plus power consumed during the estimated first and second periods; and

execute a switching of an operating frequency and an operating voltage of the performing unit, based on a value of the discriminant.

2. The power control apparatus according to claim 1 , wherein

the first information includes third information concerning a load of a task under execution by the performing unit, and

the processor estimates the first period, based on the third information.

3. The power control apparatus according to claim 1 , wherein

the second information includes fourth information indicating whether the bus is being operated for direct memory access and fifth information concerning a data volume transferred by one direct memory access, and

the processor estimates the second period, based on the fourth information and the fifth information.

4. The power control apparatus according to claim 1 , further comprising

a changing unit configured to change the operating frequency and the operating voltage of the performing unit, wherein

the processor executes the switching when the value of the discriminant is less than zero, and

the changing unit changes any one among the operating frequency and the operating voltage of the performing unit to the operating frequency or the operating voltage determined for the performing unit by the processor, if the processor executes the switching.

5. The power control apparatus according to claim 1 , wherein

the processor collects for each performing unit among a plurality of the performing units, the first information,

the processor determines for each performing unit among the plurality of performing units, the operating frequency and the operating voltage,

the processor estimates for each performing unit among the plurality of the performing units, the first period, determines for each performing unit among the plurality of the performing units, power consumed during the estimated first period, and sums the power as the total power consumption, and

the processor executes the switching when among the plurality of the performing units, a performing unit is present for which a post-switching operating frequency and a post-switching operating voltage are less than a pre-switching operating frequency and a pre-switching operating voltage and for other performing units among the plurality of the performing units, the post-switching operating frequency and the post-switching operating voltage are less than or equal to the pre-switching operating frequency and the pre-switching operating voltage.

6. An electronic computer comprising:

a performing unit configured to perform data processing; and

a bus configured to transfer data; and

a processor configured to:

collect first information related to operation of the performing unit and second information related to operation of the bus;

determine an operating frequency and an operating voltage for the performing unit, based on the first information and the second information;

estimate based on the first information and the second information, a first period elapsing until the performing unit suspends data processing that is being performed and a second period elapsing until the bus suspends data transmission that is being conducted;

derive a discriminant that obtains a difference of total power consumption and power consumption pre-switching, the total power consumption being power consumed in a case of switching the operation of the performing unit based on the determined operating frequency and operating voltage plus power consumed during the estimated first and second periods; and

execute a switching of an operating frequency and an operating voltage of the performing unit, based on a value of the discriminant.

7. The electronic computer according to claim 6 , wherein

the first information includes third information concerning a load of a task under execution by the performing unit, and

the processor estimates the first period, based on the third information.

8. The electronic computer according to claim 6 , wherein

the second information includes fourth information indicating whether the bus is being operated for direct memory access and fifth information concerning a data volume transferred by one direct memory access, and

the processor estimates the second period, based on the fourth information and the fifth information.

9. The electronic computer according to claim 6 , further comprising

a changing unit configured to change the operating frequency and the operating voltage of the performing unit, wherein

the processor executes the switching when the value of the discriminant is less than zero, and

the changing unit changes any one among the operating frequency and the operating voltage of the performing unit to the operating frequency or the operating voltage determined for the performing unit by the processor, if the processor executes the switching.

10. The electronic computer according to claim 6 , wherein

the processor collects for each performing unit among a plurality of the performing units, the first information,

the processor determines for each performing unit among the plurality of performing units, the operating frequency and the operating voltage,

the processor estimates for each performing unit among the plurality of the performing units, the first period, determines for each performing unit among the plurality of the performing units, power consumed during the estimated first period, and sums the power as the total power consumption, and

the processor executes the switching when among the plurality of the performing units, a performing unit is present for which a post-switching operating frequency and a post-switching operating voltage are less than a pre-switching operating frequency and a pre-switching operating voltage and for other performing units among the plurality of the performing units, the post-switching operating frequency and the post-switching operating voltage are less than or equal to the pre-switching operating frequency and the pre-switching operating voltage.

11. A power control method comprising:

collecting first information related to operation of a performing unit configured to perform data processing and second information related to operation of a bus configured to transfer data;

determining an operating frequency and an operating voltage for the performing unit, based on the first information and the second information;

estimating based on the first information and the second information, a first period elapsing until the performing unit suspends data processing that is being performed and a second period elapsing until the bus suspends data transmission that is being conducted;

deriving a discriminant that obtains a difference of total power consumption and power consumption pre-switching, the total power consumption being power consumed in a case of switching the operation of the performing unit based on the determined operating frequency and operating voltage plus power consumed during the estimated first and second periods; and

executing a switching of an operating frequency and an operating voltage of the performing unit, based on a value of the discriminant, wherein

the power control method is executed by a processor.

12. The power control method according to claim 11 , wherein

the first information includes third information concerning a load of a task under execution by the performing unit, and

the estimating includes estimating the first period, based on the third information.

13. The power control method according to claim 11 , wherein

the second information includes fourth information indicating whether the bus is being operated for direct memory access and fifth information concerning a data volume transferred by one direct memory access, and

the estimating includes estimating the second period, based on the fourth information and the fifth information.

14. The power control method according to claim 11 , wherein

the executing includes executing the switching when the value of the discriminant is less than zero, and

further comprising changing any one among the operating frequency and the operating voltage of performing unit to the operating frequency or the operating voltage determined for the performing unit at the determining, if the switching is executed.

15. The power control method according to claim 11 , wherein

the collecting includes collecting for each performing unit among a plurality of the performing units, the first information,

the determining includes determining for each performing unit among the plurality of performing units, the operating frequency and the operating voltage,

the estimating includes estimating for each performing unit among the plurality of the performing units, the first period,

the power control method further comprising:

determining for each performing unit among the plurality of the performing units, power consumed during the estimated first period; and

summing the power as the total power consumption, wherein

the executing includes executing the switching when among the plurality of the performing units, a performing unit is present for which a post-switching operating frequency and a post-switching operating voltage are less than a pre-switching operating frequency and a pre-switching operating voltage and for other performing units among the plurality of the performing units, the post-switching operating frequency and the post-switching operating voltage are less than or equal to the pre-switching operating frequency and the pre-switching operating voltage.