caredroid: adaptation framework for android context-aware ...krish/cs257/caredroid.pdf ·...

CAreDroid: Adaptation Framework for Android Context-Aware Applications

Salma Elmalaki Lucas Wanner Mani Srivastava

Networked & Embedded Systems Laboratory

1

NESLNetworked & EmbeddedSystems Laboratory

Copyright (c) 2015


Copyright (c) 20152

Photo Courtesy: Student Portal

Isolated Disconnected Unaware


Copyright (c) 2015

Computing … From Isolation to Awareness

3Photo Courtesy: Mobile innovation lab

4

Sense

5

Sense

Understand

6

Sense

Understand

Emergency

Adapt

7

Sense

Understand

Eme

Adapt

CAreDroid

8

Understand

Adapt

Challenges 1. Automatically adapt to the

environmental change at runtime. 2. Adaptation should be burden-free

for the user. 3. Overhead of reading the

environmental context should be small.

CAreDroid

Sense


Copyright (c) 2015

ACE: Exploiting Correlation for Energy-

Efficient and Continuous Context

Sensing (MobiSys’12)

What is Context-awareness?

9

adapt

sense

understand

Fusing mobile, sensor, and social data to fully enable context-aware computing

([HotMobile '10])A System Context-Aware Approach for Battery Lifetime Prediction in Smart Phones

([SAC’11])

ErdOS: Achieving Energy

Savings in Mobile

([MobiArch’11])

ContextOS: A Context Aware

Operating System for

Mobile Devices ([GreenCom’13])

The Latency Accuracy and Battery LAB Abstraction:

Programmer Productivity and Energy Efficiency for Continuous

Mobile Context Sensing ([OOPSLA’13]) Balancing Energy,

Latency and Accuracy for

Mobile Sensor Data Classification

(SenSys’11)SymPhoney: A

Coordinated Sensing Flow Execution

Engine for Concurrent Mobile

Sensing Applications (SenSys’12)


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Adaptation Realization

10

Program

f()f1()

Context-Aware System

Connectivity Battery Status

Activity

Location Temperature

Function Adaptation

Location

Activity

Battery Status

Connectivity

Temperature

f2()Location

f3()

fn()Battery Status

Activity

Location


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11

Program

f()f1()



Activity


Function Adaptation

Location

Activity

Battery Status

Connectivity

Temperature

f2()Location

f3()

fn()Battery Status

Activity

Location


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12

Program

f()f1()



Activity


Function Adaptation

Location

Activity

f2()Location

f3()

fn()

Activity

Location

CAreDroid Architecture

13

Usability Performance


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14

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer

Sensitive function registration & config parsing

ContextMonitoring

Context Sensors

AdaptationEngine

Temperature Energy Connectivity …

g

Application Layer


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15

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Application Layer

System Layer


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16

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Context Sensors

Application Layer

System Layer


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Sensitivity Configuration File

17

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g


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Function Registration

18

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

• The sensitive function registration part is responsible for: • understanding the

ranges of operations of each method

• integrate it in the Android run-time system


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Function Registration & Config. Parsing

19

extended .odex

Development time

SensitivityConfigFile

Installation time

Sensitive Method Discovery

CAr

eDrio

d Fl

ow

Sensitivity Config File

SensitivityConfigFile .java


SensitivityConfigFile .class

Compilation and packaging time

.dex


Nor

mal

And

roid

Fl

ow

.odex

Replacement MapTable of Range Identifiers

intercept

Table of Range IdentifiersTable of Range Identifiers

.apk

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow

CAreDroid flow


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extended .odex

Development time


Installation time


CAr

eDrio

d Fl

ow






.dex


Nor

mal

And

roid

Fl

ow

.odex


intercept


.apk

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow

CAreDroid flow


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21

extended .odex

Development time


Installation time


CAr

eDrio

d Fl

ow






.dex


Nor

mal

And

roid

Fl

ow

.odex


intercept


.apk

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow

CAreDroid flow


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22

extended .odex

Development time


Installation time


CAr

eDrio

d Fl

ow






.dex


Nor

mal

And

roid

Fl

ow

.odex


intercept


.apk

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow

CAreDroid flow


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Context Monitoring

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1. Battery state: capacity, temperature, voltage

2. Connectivity state: WiFi connection status, WiFi link quality, RSSI received signal strength indication

3. Location: GPS location 4. Mobility: run, walk, still

• Bypassing the HAL layer and the associated sensor managers.

• Snooping on the interface between the HAL and the low-level device drivers through the sysfs virtual file system.

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g


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Adaptation Engine

24

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

It is where the method replacement happens at runtime.


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Adaptation Engine

2525

invoke-virtual-quick

CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map

intercept Dalvik Interpreter Method ID Class Virtual

Table

Class ID,Pointer to method byte code

Execute method

CAreDroid Dalvik Interpreter Extension

Class ID

Table of Range IdentifiersTable of Range IdentifiersTable of Range Identifiers

Operation Range Identifiers CAreDroid

Decision Graph

Current Context

Replaced Method ID

Class ID,Resolution Cache update cache

Replaced Method ID

Class ID,

cache miss cache hit Method ID

Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow


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Adaptation Engine

2626


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Normal Android

flow


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Adaptation Engine

27


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow



Adaptation Engine

28


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow



Adaptation Engine

29


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow



Adaptation Engine

30


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow



Adaptation Engine

31


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

Best Fit policy Must Fit policy

CAreDroid flow

Normal Android

flow

B

T

V

S

W

Q

M

L

M1 M2 M3 M4 M5

1 2 3 4 5

2 3 4 1 2

1 4 2 3 4

1 2 3 4 5

2 2 1 3 3

4 3 2 1 2

2 3 3 1 2

1 4 3 2 3

1 2 3 4 5

1 2 3 4

1 2 3 4

1 2 3 4

1 2 3

1 2 3 4

1 2 3

1 2 3 4

5

B

T

V

S

W

Q

M

L



Adaptation Engine

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CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow


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Adaptation Engine

3333


CAr

eDrio

d Fl

owN

orm

al A

ndro

id

Flow

Replacement Map


Table


Execute method


Class ID



Decision Graph

Current Context

Replaced Method ID


Replaced Method ID

Class ID,


Class ID,

app

f f1 f2 f3

g1 g2 g3

Application Layer

SensitivityConfig

File

System Layer


ContextMonitoring

Context Sensors

AdaptationEngine


g

CAreDroid flow

Normal Android

flow

Evaluation

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1. Push context monitoring and adaptation to runtime system

2. At least 2x fewer lines of code 3. At least 10× more efficient in execution time


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Context-aware Camera

3535

Still position Walking !(non context aware)

Walking !(with CAreDroid)

Still position






37



Walking (With CAreDroid)

Walking (non-context aware)

Still position


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Analysis - Significant Line of Code (SLOC)

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Platform SLOC %Increase

Analysis of CAreDroid

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1. Analyze the effect of cache in the adaptation engine 2. Examine the overhead of context-monitoring

module 3. The difference in energy and execution time

between pure Java implementation using Android APIs and CAreDroid


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Testbed and testing environment

•Nexus 4

•Android 4.2 - API 17

•Overhead of system image is 4.6%

40


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Analysis—Execution time

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f1 f2 f3

Platform OverheadWithout cache With cache

CPU time (ms)

14.213

f1 f2 f3

f1 f2 f3

f1 f2 f3

Average of 10 executions with variance 0.5% ~ 1%


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Analysis — Energy

42

0 0.5 1 1.5 2 2.5

0

1,000

2,000

3,000

4,000

5,000

Time [hr]

En

erg

y[J]

Pure Java

Must fit

Best fit

Non-context aware

1. CAreDroid consumes only 6.73% more energy compared with the non-context aware implementation and

2. CAreDroid gives 69.33% energy saving compared to the pure Java implementation.

3. Measurements are taken every 5 seconds. Average is shown with variance < 1%


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Future Work

1. Migrate to new versions of Android that are based on ART instead of Dalvik (Kitkat and Lollipop).

2. Add support for more abstract contexts, for example, stress, smoking, fitness, … etc

3. The adaptation can be privacy-aware.

4. Time of the day is another axis that can be used to enhancing the adaptation support

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Thank you!

44

http://www.seas.ucla.edu/~salma/


Copyright (c) 2015

Keeping the developer/user in the loop

• Make the user not fully obfuscated

• Why this adaptation takes place?

• Special CAreDroid API - “read_operating_point()”

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caredroid: adaptation framework for android context-aware ...krish/cs257/caredroid.pdf ·...

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