Device power saving during exercise

1. A portable apparatus, comprising:

at least one processing unit and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processing unit, to cause the portable apparatus to perform operations comprising:

supporting a normal operation mode during which functionalities of the apparatus are available through an operating system of the apparatus, wherein the operating system comprises a plurality of layers including a kernel and library functions -layer;

supporting a limited operation mode during which the apparatus is configured to execute a physical activity algorithm based on physical activity data corresponding to a physical activity session performed by a user of the apparatus, wherein the physical activity algorithm applies a direct low-level hardware access bypassing at least the layers above the kernel and the library functions -layer; and

switching between the normal operation mode and the limited operation mode, wherein the at least one processing unit comprises:

a low power processing unit configured to run at least the physical activity algorithm during the limited operation mode; and

a high power processing unit configured to run the operating system of the apparatus during the normal operation mode, wherein the low power processing unit has a lower power consumption in performing a given task than the high power processing unit, and wherein a switch to the limited operation mode comprises:

activating the low power processing unit to run at least the physical activity algorithm; and

inactivating the high power processing unit.

2. The apparatus of claim 1 , wherein the operations further comprise:

inactivating at least predetermined layers of the operating system when entering the limited operation mode.

3. The apparatus of claim 1 , wherein a set of functionalities of the apparatus is available to the apparatus during the normal operation mode and only a predetermined subset of the functionalities is available to the apparatus during the limited operation mode.

4. The apparatus of claim 1 , wherein the apparatus further comprises a power supply for providing power for the operation of the apparatus, and wherein the operations further comprise:

detecting the power status of the power supply;

determining current power consumption rate of the apparatus;

comparing the power consumption rate and the power status; and

on the basis of the comparison result, deciding on the switching between the normal operation mode and the limited operation mode.

5. The apparatus of claim 1 , wherein the physical activity algorithm causes obtaining physical activity data from at least one physical activity sensor associated with the apparatus and storing of the received physical activity data.

6. The apparatus of claim 1 , wherein the physical activity algorithm causes determination of at least one of the following: heart activity of the user, activity metric of the user, accumulated metric with respect to the physical activity session.

7. The apparatus of claim 1 , wherein the operations further comprise:

detecting the beginning of the physical activity session; and

deciding to switch to the limited operation mode at the beginning of the physical activity session.

8. The apparatus of claim 1 , wherein the operations further comprise:

detecting the power status of the power supply;

obtaining the remaining duration of the ongoing physical activity session;

comparing the power status to the remaining duration of the ongoing physical activity session; and

on the basis of the comparison result, deciding whether or not to switch to the limited operation mode.

9. The apparatus of claim 1 , wherein the operations further comprise:

detecting that the physical activity session is ended; and

entering the normal operation mode.

10. The apparatus of claim 1 , wherein the operations further comprise:

estimating the ending time of the current physical activity session; and

starting to activate the operating system at least a predetermined activation duration before the current physical activity session is to be ended, wherein the predetermined activation duration substantially corresponds to the time duration it takes for the operating system to activate.

11. The apparatus of claim 1 , wherein the functionalities not available in the limited operation mode include at least one of the following: touch sensitivity of a display of the apparatus, social media support, call and message support.

12. The apparatus of claim 1 , wherein the operations further comprise:

detecting an exercise profile of the ongoing physical activity session;

determining which physical activity -related functionalities are needed during the limited operation mode on the basis of the detected exercise profile; and

running the determined physical activity -related functionalities during the limited operation mode via the physical activity algorithm.

13. The apparatus of claim 1 , wherein the operations further comprise:

dynamically limiting the usage of at least one physical activity -related functionality during the limited operation mode.

14. The apparatus of claim 13 , wherein the operations further comprise:

obtaining power consumption information indicating how different physical activity -related functionalities of the apparatus affect the power consumption rate of the apparatus;

obtaining functionality usage information indicating which physical activity -related functionalities are typically used during a physical activity session performed by the user; and

determining the at least one physical activity -related functionality whose usage is to be limited on the basis of the power consumption information and the functionality usage information.

15. The apparatus of claim 14 , wherein the power consumption information and the functionality usage information are updated after each physical activity session.

16. The apparatus of claim 1 , wherein the operations further comprise:

determining the temperature of the apparatus and/or the ambient temperature;

obtaining temperature information indicating how temperature affects the power consumption rate of the apparatus; and

deciding whether or not to perform functional limitations on the basis of the determined temperature and the obtained temperature information.

17. The apparatus of claim 1 , wherein the apparatus is a wrist-worn watch.

18. The apparatus of claim 1 , wherein the apparatus further comprises:

at least one first memory unit configured to be used during the limited operation mode; and

at least one second memory unit configured to be used during the normal operation mode, wherein the second memory unit is not used during the limited operation mode.

19. The apparatus of claim 18 , wherein the first memory unit comprises static random access memory, SRAM, and the second memory unit comprises double data rate synchronous dynamic random access memory, DDR-SDRAM.

20. The apparatus of claim 1 , wherein the operations further comprise:

deciding to switch to the limited operation mode;

inactivating a kernel of the operating system; and

running the physical activity algorithm on the at least one processing unit.

21. The apparatus of claim 20 , wherein the operations further comprise:

booting the operating system of the apparatus; and

upon powering up the operation system, restraining from switching the kernel on, and executing the physical activity algorithm by the at least one processing unit.

22. The apparatus of claim 1 , wherein the apparatus further comprises an external memory unit, and wherein the apparatus is further caused to perform:

running the kernel of the operating system via the external memory unit; and

running the physical activity algorithm on the at least one processing unit.

23. The apparatus of claim 1 , wherein the low power processing unit is a microcontroller unit without a memory management unit, and the high power processing unit is a microprocessor unit with a memory management unit.

24. A method, comprising:

supporting a normal operation mode during which functionalities of an apparatus are available through an operating system of the apparatus, wherein the operating system comprises a plurality of layers including a kernel and library functions -layer;

supporting a limited operation mode during which the apparatus is configured to execute a physical activity algorithm based on physical activity data corresponding to a physical activity session performed by a user of the apparatus, wherein the physical activity algorithm applies a direct low-level hardware access bypassing at least the layers above the kernel and the library functions -layer;

switching between the normal operation mode and the limited operation mode;

running, using a low power processing unit, at least the physical activity algorithm during the limited operation mode; and

running, using a high power processing unit, the operating system of the apparatus during the normal operation mode, wherein the low power processing unit has a lower power consumption in performing a given task than the high power processing unit, and wherein a switch to the limited operation mode comprises:

activating the low power processing unit to run at least the physical activity algorithm; and

inactivating the high power processing unit.

25. A computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when executed by an apparatus, execute a method comprising:

supporting a normal operation mode during which functionalities of the apparatus are available through an operating system of the apparatus, wherein the operating system comprises a plurality of layers including a kernel and library functions -layer;

supporting a limited operation mode during which the apparatus is configured to execute a physical activity algorithm based on physical activity data corresponding to a physical activity session performed by a user of the apparatus, wherein the physical activity algorithm applies a direct low-level hardware access bypassing at least the layers above the kernel and the library functions -layer;

switching between the normal operation mode and the limited operation mode;

running, using a low power processing unit, at least the physical activity algorithm during the limited operation mode; and

running, using a high power processing unit, the operating system of the apparatus during the normal operation mode, wherein the low power processing unit has a lower power consumption in performing a given task than the high power processing unit, and wherein a switch to the limited operation mode comprises:

activating the low power processing unit to run at least the physical activity algorithm; and

inactivating the high power processing unit.