CONTEXT BASED POWER MANAGEMENT
According to some embodiments, context information associated with a processing system may be determined. It may then be automatically arranged for a power state associated with the processing system to transition from a first power state to a second power state based on the context information.
The present application is a continuation of U.S. patent application Ser. No. 10/933,886 entitled “Context Based Power Management” and issued as U.S. Pat. No. 7,565,562 on Jul. 21, 2009. The entire content of that application is incorporated herein by reference.
BACKGROUNDA processing system consumes power as it operates. For example, a processing system associated with a mobile computer might consume power from a battery. As the performance of a processing system is improved (e.g., by increasing the speed of the processor, allowing wireless communication, providing a larger display, and/or executing more complex applications), the amount of power consumed by the processing system may increase. As a result, a battery may need to be re-charged more frequently, which might be annoying for a user. Note that increasing the size of the battery might be impractical (e.g., because it would make a mobile computer too large).
To conserve power, a processing system and/or a subsystem within the processing system may have a number of different power states. For example, the processing system or subsystem might operate in a higher-power state when it is actively being used and in a lower-power state during periods of relative inactivity (e.g., a hard disk drive might be transitioned to a lower-power state when it has not been accessed for five minutes). In some cases, however, a processing system or subsystem may not be transitioned to a lower-power state. For example, a subsystem might not be placed in a placed in a lower-power state even when a user is not executing any applications that require that subsystem.
Some embodiments described herein are directed to a “processing system.” As used herein, the phrase “processing system” may refer to any apparatus that includes one or more processors. Examples of processing systems include a desktop Personal Computer (PC), a mobile computer, a workstation, a server, a set top box (e.g., associated with a digital television receiver), a wireless telephone, and a game system.
For example,
The processing system 100 includes a power policy manager 150. The power policy manager 150 might, for example, be associated with an operating system that is being executed by a processor (e.g., one of the subsystems 102). The power policy manager 150 may place the processing system 100 (including any of the subsystems 102) in a number of different power states. For example, the power policy manager 150 might place a hard disk drive in a lower-power state when it has not been accessed for ten minutes.
According to some embodiments, the power policy manager 150 evaluates context information associated with the processing system 100, and arranges for a power state associated with the processing system 100 (e.g., including any of the subsystems 102) to transition from a first power state to a second power state based on the evaluation. According to some embodiments, the power policy manager 150 operates in accordance with one or more context aware power manager extensions.
At 202, context information associated with a processing system is determined. As described with respect to
The context information may also be based on a user usage pattern. For example, the context information might indicate that a first user of a hand-held device typically listens to a single song while a second user typically listens to many songs (and often takes thirty seconds to select his or her next song).
At 204, it is “automatically” arranged for a power state associated with the processing system to transition from a first power state to a second power state based on the context information. As used herein, the term “automatically” refers to an action that is performed without requiring an input from a user. Note that the power state might be adjusted directly by a power manager or by adjusting an existing power policy (e.g., reducing a time-out period).
For example, a laptop computer might automatically implement a first set of power management policies if it is currently between 9:00 AM and 5:00 PM on a work day and a second set of policies if it is not. In the case of a user usage pattern, for example, a hand-held device might automatically turn off an audio subsystem after a first user finishes listening to a song but not turn off the audio subsystem after a second user finishes listening to a song (e.g., because he or she is likely to select another song).
In addition, the processing system 300 may include a display 306 (e.g., the screen of a hand-held device), a communication subsystem 308, and a printer 310. The communication subsystem 308 might, for example, exchange information via a communication network in accordance with third generation (3G) wireless, Global System for Mobile (GSM), and/or Bluetooth communications. By way of example, the communication subsystem 308 may transmit and/or receive information via a Wireless Local Area Network (WLAN) that operates in accordance with an Ethernet protocol and/or a Code-Division Multiple Access with Collision Avoidance (CDMA/CA) protocol, such as the one defined by Institute of Electrical and Electronics Engineering (IEEE) specification number 802.11g (2003).
The processing system 300 also includes a processor 350 that may execute an operating system and one or more applications. For example, the processor 350 might execute the MICROSOFT® WINDOWS® XP operating system, the MICROSOFT® INTERNET EXPLORER 5.0® web browser, and a media player adapted to play MP3 songs.
The processor 350 or some other component may also include a power manager that operates in accordance with the Advanced Configuration and Power Interface (ACPI) Specification Revision 2.0b (October, 2002). For example, the processor 350 might be able to operate in a number of different “sleep” states, such as S0 (fully operational and consuming the most power); S1 (a low wake latency sleep state after which no system context is lost); and S2 (a low wake latency sleep state after which processor and system cache context needs to be restored). Moreover, frequency and voltage scaling may be used to reduce the amount of power consumed by the processor 350.
In addition to sleep states, the processing system 300 may be able to operate in various global states, device power states, processor power states, and/or performance states. Note that the ACPI specification defines global states G0 through G3, device power states D0 through D3 (and device performance states P0 through Pn within D0), and processor power states C0 through C3. That is, the performance and power requirements of various subsystems 302, 304, 306, 308, 310 may be individually controlled.
For example, referring again to
Moreover, the hard disk drive 302 is in a normal state, the audio subsystem 304 is on (e.g., to play the MP3 files), the display 306 is bright (e.g., so the user can view web pages), and the communication subsystem 308 is on (e.g., to let the user access the Internet). Note that the printer subsystem 310 is off (e.g., because neither application is likely to use the printer 310), which may reduce the amount of power being used by the processing system 300.
At 404, it is arranged for a power state associated with a subsystem to transition from the first power state to the second power state based on said evaluation. For example, one or more subsystems may be transitioned to a lower-power state (e.g., to a lower-power ACPI device or performance state) when they are not likely to be used any application currently being executed.
For example,
Moreover, the performance of the hard disk drive 302 may be optimized to support the MP3 player. In this example, the power state of the audio subsystem 304 has not been changed (since the audio subsystem 304 is required by the MP3 player). The display 306 has been placed in a “dim” power mode (e.g., because the user is not likely to be looking at the display) and the communication subsystem 308 has been turned off completely in order to reduce the amount of power being used by the processing system 300. As a result, the life of a battery used to power the processing system 300 may be extended.
In addition to evaluating the applications that are being executed, other context information may be used to adjust power states. For example,
The external condition might be, for example, an amount of ambient light. In this case, a processing system might use a light sensor to place a subsystem in a higher-power state when a user enters a dark room and turns on the light (e.g., because he or she is more likely to use the subsystem). As another example, a motion associated with a processing system may be detected and used to adjust a power state. For example, a hand-held computer might transition to a higher-power state when it is picked up by a user. As another example, a location associated with the processing system may be detected. For example, a wireless telephone subsystem might automatically transition to a lower-power state when the processing system detects that it is in the user's home or not within range of wireless service. As still another example, a location associated with a remote device might be detected. For example, a display subsystem on a laptop computer might be transitioned to a “bright” state when the laptop computer detects that a digital camera has been moved nearby (e.g., to let a user view pictures from the camera via a Bluetooth interface).
To save power, the ACPI system 700 may enter a number of different power states. The various power states may represent, for example, states in which the system 700 consumes an increasingly lower amount of power and application 770 instructions are not being executed by a processor in the platform hardware 710 (e.g., ACPI sleep states S1 or S2). In other power states, the system 700 may appear to be “turned off” to a user, such as when in ACPI sleep state S3, also referred to as “suspend to RAM” and ACPI sleep state S4, also referred to as “hibernate.”
One or more of the elements in the system 700 (or some other element not shown in
According to some embodiments, the power manager simply decides whether or not a particular subsystem can be turned “off” based on the applications that are currently being executed. In this case, the power manager may perform a Boolean OR operation on subsystem requirements associated with a plurality of applications 770 that are currently being executed. The power manager may then arrange for a power state associated with system 700 (e.g., including any subsystem) to transition either “on” or “off” based on the result of the Boolean OR operation (e.g., the subsystem will be turned on when at least one application requires it).
In addition to simply turning a subsystem “on” or “off,” the power manager may adjust a power state to any number of other levels (e.g., a display might be set to 20% brightness). For example, the following software algorithm might be used to provide power state transitions for a processing system that has n subsystems (e.g., devices) and that is able to execute j different applications:
While (forever)//in this example, the algorithm is being executed periodically
That is, when a new application begins to execute, the algorithm will determine the minimum amount of resources that the application needs on a device-by-device basis (e.g., the new application requires at least 20% brightness for a display and a fully operational communication subsystem). Similarly, when an application stops executing the performance profile may be adjusted as appropriate (e.g., to 0% brightness and no need for a communication subsystem at all). The algorithm then selects the maximum value for each device and adjusts the power state of devices as appropriate.
Consider, for example, a processing system that is currently executing three applications. The first application requires a 40% brightness level, the second application requires a 90% brightness level, and the third application requires a 50% brightness level. In this case, the power manager may set the brightness level of a display subsystem to 90%. When the user closes the second application, the power manager may adjust the brightness level of the display subsystem to 50% (and thereby save power and increase the amount of time a battery will be able to power the system).
The following illustrates various additional embodiments. These do not constitute a definition of all possible embodiments, and those skilled in the art will understand that many other embodiments are possible. Further, although the following embodiments are briefly described for clarity, those skilled in the art will understand how to make any changes, if necessary, to the above description to accommodate these and other embodiments and applications.
Although ACPI power states have been used herein as an example, embodiments of the present invention may be associated with any type of lower-power state. Moreover, although specific components have been described as performing specific functions, any of the functions described herein might be performed by a software application, a hardware device, an operating system, a driver, and/or a BIOS.
The several embodiments described herein are solely for the purpose of illustration. Persons skilled in the art will recognize from this description other embodiments may be practiced with modifications and alterations limited only by the claims.
Claims
1. A method, comprising:
- automatically evaluating subsystem usage associated with a plurality of applications being executed by a processing system;
- sensing a user generated condition external to the processing system that represents a potential usage of the processing system by a user; and
- automatically arranging for a power state associated with the processing system to transition from a first power state to a second power state based on said evaluation and external condition.
2. The method of claim 1, wherein said arranging comprises:
- arranging for a power state associated with a subsystem to transition from the first power state to the second power state based on said evaluation and external condition.
3. The method of claim 2, wherein at least one of the subsystems comprises at least one of: (i) a processor, (ii) a hard disk drive, (iii) an audio subsystem, (iv) a display device, or (v) a communication device.
4. The method of claim 3, wherein the power state is an advanced configuration and power interface specification power state.
5. The method of claim 4, wherein the power state is associated with at least one of: (i) a global state, (ii) a device power state, (iii) a sleep state, (iv) a processor power state, or (v) a performance state.
6. A method, comprising:
- automatically determining context information associated with a processing system that includes a number of subsystems, wherein said determining comprises sensing a user generated condition external to the processing system that represents a potential usage of the processing system by a user; and
- automatically arranging for a power state associated with the processing system to transition from a first power state to a second power state based on the context information.
7. The method of claim 6, wherein the external condition is associated with at least one of: (i) ambient light, (ii) a motion associated with the processing system, (iii) a location associated with the processing system, or (iv) a location associated with a remote device.
8. The method of claim 7, wherein the power state is an advanced configuration and power interface specification power state.
9. The method of claim 8, wherein the power state is associated with at least one of: (i) a global state, (ii) a device power state, (iii) a sleep state, (iv) a processor power state, or (v) a performance state.
10. The method of claim 6, wherein said arranging is performed in accordance with a context-aware power management extension and an operating system power policy manager.
11. The method of claim 6, wherein the processing system comprises at least one of: (i) a desktop personal computer; (ii) a mobile computer, (iii) a workstation, (iv) a server, (v) a set-top box, (vi) a wireless telephone, or (vii) a game system.
12. The method of claim 6, wherein said determining is performed by at least one of: (i) a software application, (ii) a hardware device, (iii) an operating system, (iv) a driver, or (v) a basic input/output system.
13. An apparatus, comprising:
- a plurality of subsystems;
- a processor; and
- a power manager to: (i) automatically evaluate context information associated with the apparatus, wherein the context information is based at least in part on an evaluation of subsystem requirements associated with a plurality of applications currently being executed by the processor, (ii) sensing a user generated condition external to the apparatus that represents a potential usage of the apparatus by a user, and (iii) automatically arrange for a power state associated with the apparatus to transition from a first power state to a second power state based on the evaluation and external condition.
14. The apparatus of claim 13, wherein at least one of the subsystems comprises at least one of: (i) a processor, (ii) a hard disk drive, (iii) an audio subsystem, (iv) a display device, or (v) a communication device.
15. The apparatus of claim 13, wherein the apparatus further includes a sensor to sense the external condition.
16. The apparatus of claim 15, wherein the sensor comprises at least one of: (i) an ambient light sensor, (ii) a motion sensor, or (iii) a location sensor.
17. The apparatus of claim 13, wherein the power state is an advanced configuration and power interface specification power state and is associated with at least one of: (i) a global state, (ii) a device power state, (iii) a sleep state, (iv) a processor power state, or (v) a performance state.
18. The apparatus of claim 13, wherein the power manager is an operating system power policy manager adapted to use context-aware power manager extensions.
19. A computer system, comprising:
- a plurality of subsystems;
- a processor;
- a battery to supply power to the processor; and
- a power manager to: (i) automatically determine minimum subsystem requirements associated with a plurality of applications being executed by the processor, (ii) sense a user generated condition external to the computer system that represents a potential usage of the computer system by a user, and (iii) automatically arrange for a power state associated with a subsystem to transition from a first power state to a second power state based on a largest minimum subsystem requirement for that subsystem and the external condition.
20. The computer system of claim 19, wherein the power state is an advanced configuration and power interface specification power state and is associated with at least one of: (i) a global state, (ii) a device power state, (iii) a sleep state, (iv) a processor power state, or (v) a performance state.
Type: Application
Filed: Jul 20, 2009
Publication Date: Nov 19, 2009
Inventor: Ram V. Chary (Portland, OR)
Application Number: 12/505,813
International Classification: G06F 1/32 (20060101);