User-Aware Power Management for Mobile Devices

05/02/2023 03:23 PM

Geunsik Lim, Changwoo Min, Dong Hyun Kang, and Young Ik Eom

Sungkyunkwan University, KoreaSamsung Electronics Co., Ltd., Korea

IEEE GCCE 2013

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Introduction Breakdown of power consumption in mobile Our proposal

User-aware power management Evaluation Conclusion

Outline

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Battery Monitor Powertutor AppScope JuiceDefender

Physical Extension External Battery Solar Recharger

How to extend battery lifeH

ardw

are

Soft

war

e

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1. Turn off radios like WiFi, Bluetooth etc : If you don’t need them, turn them off. You don’t need GPS or Bluetooth all the time.

2. Turn off apps that use more battery: You can close the applications (e.g. running applications, sync) you don’t need to supply battery.

3. Decrease Screen Brightness & Screen time-out: You can decrease brightness to save battery little more

4. Turn on Airplane Mode : Airplane Mode is useful if you don’t need to connect to WiFi or mobile data networks.

Extending battery life by users

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• Typical pattern of power consumption of a mobile device without running any user applications (factory reset).

• The breakdown of each factor about degradation of battery lifespan.• Platform developers does not report no cases of battery degradation.

* Experimental Device: Galaxy S2 (1,650mAh)

Breakdown of power consumption in mo-bile

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How should “Our idea” …1. Recognize the idle time of users?2. Execute wake-up automatically from shutdown sta-

tus?3. How can user control?

Challenges: a great way to get new in-sights

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• Our approach is a system that consists of the RTC-based kernel fea-ture and the user-space mobile app to extend battery life.

• The major goal of Our system is to control the turn-off and reboot operation as well as suspend-to-ram/suspend-to-disk during the sleep period of customers.

After1 day

After2 days

After3 days

After0 day

User-Aware Power Management for Mobile Devices!!!

Problem Create idea How

What is our idea?

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Hardware

Ker

nel-s

pace

(4) B

atte

ry

Tim

er

(3) S

leep

Lev

el

Con

trol

ler

(2) Sleep Time Manager

(1) User-space Client

Memory Susp

end-

To-R

AM

Susp

end-

To-D

isk

Com

plet

e O

ff

Overall diagram of proposed system 1/2

Time SchedulingBased on RTC-Timer

User-space ClientSTART

Sleep Time Manager Suspend-To-RAM (S3)Suspend-To-Disk

Turn-Off

Power Saving Level == {1|

2|3}

Wake-up (By Battery Timer)Service Restoration END

(1)(2)(3)

Over

all A

rchi

tect

ure

Entir

e Fl

ow D

iagr

am

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Suspend-To-RAM

Suspend-To-Disk

Complete Off

Sleep Ex-ecutor

TimeWakeup

H/W Timer

Auto Wake-up

Saving Time(Time to reduce

power consumption)Time

Checker

User spaceApplica-

tion

Middle ware

User spaceApplica-

tion

Energy Miser Client

User spaceApplica-

tion

User spaceApplica-

tion

User

-spa

ceKe

rnel

-spa

ce

Sleep

(4) Battery Timer

(3) Sleep Level Controller

(2) Sleep Time Man-ager

(1) User-space Client

Memory

Overall diagram of proposed system 2/2

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Sleep()

/sys/…/current_clocksource

UserKernel

Hardware

gettimeofday() clock_* API nanosleep()

do_gettimeofday() xtime HRT (High Resolution Timer)

ClocksourceFramework

ClockeventFramework

APICJiffies ACPI TSC

PITHPET

ITimer API

…

RTC

Overall structure of RTC-based H/W timer• Timekeeping using clocksource and clockevents based on RTC timer.

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• User-aware UI interface for complete automation.

Suspend-to-re-sume

Suspend-to-disk

Complete-off

By in-terrupt

30 Min.

1 Hour

30 Min.

1 Hour

2 Hour

Cus-tomize

Cus-tomize

Wakeup TimeSleep Time

Check the period of display-off status “Wakeup Time”

If display-off period happens again, repeat the execution of “Wakeup time/Sleep time”

If the display-off period is big-ger than user-setting, Execute one of the three methods “Sleep Level”. Restart services after “Sleep Time”.

Start

End

Sleep Level

Relation between user-space client and op-eration

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Because of turn-on of some periph-eral devices (Just, Engineering issue)

Evaluation: w/o additional user apps

• Galaxy S2: 1,650mAh • Galaxy S3: 2,100mAh• Nexus 7: 4,325mAh• Laptop : 4,400mAh

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*Active devices (WiFi, Bluetooth, GPS)*Sync (Gmail, Facebook, etc)*Background daemons (Skype, Kakao)

• Galaxy S2: 1,650mAh • Galaxy S3: 2,100mAh• Nexus 7: 4,325mAh• Laptop : 4,400mAh

Evaluation: w/ additional user apps

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• Even when users do not use any applications, battery lifespan decreases continually. e.g., (1) device operations & service daemons and (2) application daemons

• A new power management system that controls the power supply completely via four major components such as (1) user-space client, (2) sleep time manager, (3) sleep level controller, and (4) battery timer.

• Our system extends the battery lifespan compared to the existing system.a. w/o additional user applications: power saving is

18%b. w/ additional user applications: power saving is

34%

• In addition, proposed system reschedules automatically all services in advance before the user tries to reuse the mobile device.

Conclusion

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Thank you for your at-tention.

Any questions?

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1. Who cares about Timer-based phone. Can you do it for Window and iPhone?

2. Are you one of those who don’t care about the power consumption for restarting of service dae-mons?

3. Sounds too good. Are there any limitations?4. Are you going to release it? Or is it a one of pa-

per?5. I totally don’t get why you are doing this?

FAQ

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1. This approach is Hardware-based software solu-tion. But, the most of mobile devices have H/W alarm timer.

2. Users needs to do battery consumption to re-launch the services of mobile platform. (Up to 1%)

3. If you can always use battery adapter in your real life? We only focus on the battery lifespan in the mobility view.

Limitation

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BACKUP SLIDESIn Case We Have More Time…

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Related Work: Power Tutor

• Power tutor• Mian Dong and Lin Zhong, “Self-constructive, high-rate energy mod-

eling for battery-powered mobile systems,” in Proc. of the ACM/USENIX Int. Conf. Mobile Systems, Applications, and Services (Mo-biSys), June 2011.

Architecture of Sesame with three major components: data col-lector, model constructor and model manager

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Related Work: App-Scope

• AppScope• C. Yoon, D. Kim, W. Jung, C. Kang, and H. Cha, “Appscope: Applica-

tion energy metering framework for android smartphone using kernel activity monitoring,” in Proc. of the USENIX Annual Techni-cal Conference (USENIX ATC), s2012.

AppScope overview on Android platform

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Related Work: Power Scheduling Algorithm

• R. Nathuji and K. Schwan, “Reducing system level power consumption for mo-bile and embedded platforms,” in Proc. of the ARCS'05 Proceedings of the 18th international conference on Architecture of Computing Systems conference on Systems Aspects in Organic and Pervasive Computing, pp. 18-32, 2005.

• A new process scheduling algorithm which accumulates device usage informa-tion in the form of device windows to make power a first class resource

Bursting Device Accesses

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Related Work: Energy-aware application Performance

• T. Simunic, L. Benini, P. Glynn, and G. D. Micheli, “Dynamic power management for portable systems,” in Proc. of the 6th annual in-ternational conference on Mobile computing and networking (Mo-biCom),” pp. 11-19. 2000.

• The time-indexed SMDP model (TISMDP) that we use to derive op-timal policy for DPM(Dynamic Power Management) in portable systems.

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Related Work: DFS-based Power Saving Algorithm

The operating frequency of CPU is dynamically changed in accordance to the estimated processing burden of each video frame. The frame-based dynamic frequency scaling is applied to the MPEG4 video decoding in the portable kitchen TV system, (e.g., AR-M926EJ-S Processor)

Summary: Dynamic Frequency Scaling Based Power Saving Algorithm for a Por-table Kitchen TV Won-Jong Kim (Chung-Ang University, Korea)

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Related Work: Accurate GPU Power Es-timation

GPU Applications, GPU Power Consumption Analysis, GPU Power

Previous works: utilization based, system call based <-- on-line power profiling techniques

The power profile obtained from each technique with that obtained from a hardware power monitoring device.

To calculate accuracy, we compare the power profile ob-tained from each technique with that obtained from a hard-ware power monitoring device.

Summary: Accurate GPU Power Estimation for Mobile Device Power ProfilingMinyong Kim (Korea University, Korea)

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Related Work: Battery Manager (by Google)

Battery Manager related JAVA APIshttp://developer.android.com/reference/android/os/BatteryManager.html

Monitoring the Battery Level and Charging Statehttp://developer.android.com/training/monitoring-device-state/battery-monitoring.html

Optimizing Battery Life http://developer.android.com/training/monitoring-device-state/index.html

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