An Energy Consumption Framework for Distributed Java-Based Systems

Chiyoung SeoSoftware Architecture Research Group

University of Southern California

Contents

Motivation JVM Platform and Life Cycle Energy Consumption Model

Computational Cost Communication Cost

Design Time Energy Estimation Runtime Energy Estimation Conclusion

Motivation (1/2)

Newly emerging computing platforms (PDAs, cellular phones, wearable computers)

Limited battery resources Distributed mobile applications require much battery p

ower in these platforms Energy-aware initial deployment of software components Dynamic adaptations of software components during runtime

Framework for estimating the energy consumption of software components is necessary

Both during system construction time and during runtime

Motivation (2/2)

Host 1 Host 2

Host 3 Host 4 Host 5

1 2

34

5

67

89

1011

12

13 14

15 16

17 18

1920

21 22

2324

2526

2627

2829

30

PDA (Linux

)

Laptop (Window XP)

PDA Cellular phone(Window CE)

Cellular phone

Encryptioncomponent

10 Joules/invocation

15 Joules/invocation

JVM Platform and Life Cycle

Java Applications

Java Class Libraries(Base, AWT, net, …)

Java Virtual Machine

Native Libraries

Operating System

Start JVM

InitializingJVM

Loadingthe main class

Interpreterloop

Exit

Main thread

GC thread

Energy Consumption Model Modeling a system’s energy consumption at

the level of its software components Allows the dynamic adaptation of a entire software

system at the component levels Energy consumption of a software component

Computational energy cost Communication energy cost

Computational energy cost CPU processing and memory accesses

Communication energy cost Data exchange among software components over

the network

Computational Energy Cost (1/4)

Focusing on a component’s constituent interfaces

H1

C1 …

I1

I2

In

C4

C2

C6

C3

C5

C7

H2

H3

H4

1 11 1

1

( , ) ( , )

: total # of interfaces for a component

: total # of invocations for an interface

( , ) : computational energy consumption for the invocation of

imn

comp ii j

i i

i th

EC c h CompEC I j

n c

m I

CompEC I j j

iI

Computational Energy Cost (2/4)

Effect of invoking an interface Represented as the execution of 256 Java bytecode types as well as

native methods (e.g., java.io.FileInputStream.read() ) In a multi-threaded environment, monitor enter/exit operations for syn

chronizing multiple threads are also executed Energy consumption for the jth invocation of a component c1’s interf

ace I1

255

1 , ,0 1

,

,

( , )

: # of each type of bytecode executed during the invocation

: # of each native method executed du

m

k j k l j l j monitork l

k j th

l j

CompEC I j bNum bEC fNum fEC mNum E

bNum k j

fNum l

ring the invocation

: # of the monitor operations executed during the invocation

: Energy consumption of executing each type of bytecode

: Energy consumption of executing each native

th

j th

k

l

j

mNum j

bEC

fEC method

: Energy consumption for a monitor operationmonitorE

Computational Energy Cost (3/4)

Garbage collection During the garbage collection, all threads except a GC thread withi

n a JVM process stop temporarily Estimating its energy consumption (Joules)

Monitor the total time tgc spent by a GC thread during an interface’s invocation

Multiply tgc by the avg. power pgc (Joules/sec.) during the garbage collection

Implicit OS routines are generally invocated while user applications are being executed

Context switching (including timer interrupt and rescheduling), page faults, page reclaims

Should be added into the computational energy cost

Computational Energy Cost (4/4)

255

1 , ,0 1

,

( , )

: Average power consumption during the garba

m

k j k l j l j monitork l

gc gc j j j j

gc

CompEC I j bNum bEC fNum fEC mNum E

p t CSNum CSEC PFNum PFEC PRNum PREC

p

,

ge collection

: Total time spent by a GC thread during the invocation

: # of context switching events during the invocation

: # of page faults occurred during the invocation

gc j th

j th

j th

t j

CSNum j

PFNum j

: # of page reclaims occurred during the invocation

: Energy consumption of processing a context switching event

: Energy consumption of processing a page fault

: Energy consump

j thPRNum j

CSEC

PFEC

PREC tion of processing a page reclaim

Communication Energy Cost (1/3)

H1

C1 …

I1

I2

In

C4

C2

C6

C3

C5

C7

H2

H3

H41 11 1

1

( , ) ( , )

: total # of interfaces for a component

: total # of invocations for an interface

( , ) : communication energy consumption for the invocation of

imn

comm ii j

i i

i th

EC c h CommEC I j

n c

m I

CommEC I j j

iI

Communication Energy Cost (2/3)

Energy Consumption for remote communication

Component c1’s interface I1

kernel’s networking subsystem

Wireless InterfaceCard

Component c2

kernel’s networking subsystem

Wireless InterfaceCard

Wirelessrouter

Host 1 Host 2

User-to-kernel copy cost

TCP/IP processingcostKernel-to-WICcopy cost

Radio Communication

cost

Communication Energy Cost (3/3) Suppose during the jth invocation of an interface I1 on Host 1

Host 1 transmits dt bytes of data to Host 2 Host 1 receives dr bytes of data from Host 2

If there are no communication failures, and the avg. transmission/ receipt BWs on Host 1 in interacting with Host 2 are bt and br bytes/sec, respectively

Energy consumption on Host 1 due to the transmission

If the avg. bandwidth is reduced to bt /2 bytes/s, then Energy consumption on Host 1 due to the receipt

Communication energy cost due to the jth invocation of I1

2t t tm d c t

: Energy consumption to send a unit of data (1 byte)

: Network communication start-up cost

t t t t

t

E m d c

m

c

1( , ) ( )t t t r r rCommEC I j m d c m d c

r r r rE m d c

Design Time Energy Estimation (1/3)

Computational energy cost for a component For each target host, the following information should be available

Energy consumption (Joules) of each bytecode and native method, a monitor operation, and implicit OS routines

Average power (Joules/sec) during the garbage collection This is just an one-time effort

JavaComponents

PDA (iPAQ)

Power Supply

DigitalMultimeter

Data CollectionComputer

Experimental setup

Design Time Energy Estimation (2/3) Identifying three types of component interfaces

An interface requiring almost the same amount of computation regardless its input parameters

Count the number of bytecodes, native methods, monitor operations, and implicit OS routines only once for an arbitrary input

At the same time, monitor the time spent by a GC thread An interface whose input size is proportional to the amount of computatio

n required Use multiple regression technique

An interface whose input parameters have no direct relationship to the amount of computation

Generate a set of random inputs using the test input generation tools Count the number of bytecodes, native methods, monitor operations, and impl

icit OS routines executed for each input Monitor the time spent by a GC thread for each input

Multiple regression for the find interface of Shortest-Path component

Estimated (J)

Actual (J)

119767

122688

Point 1

261905

245395

Point 2

351300

364891

Point 3

224201

215760

Point 4

341570

316622

Point 5

677319

710709

Point 6

X2 (Num. of edges)

Y (E

nerg

y, μ

J)

Y (E

nerg

y, μ

J)

X1 (Num. of nodes)

1

2

3

4

5

6

1 2 3 4 5 6 7 8 9 10

SHA MD5 IDEA

Median

Filter

LZW Sort DB Shortest path

AVL

Linked List

Error rate=(calculated value – measured value) * 100 / measured value

- 8

- 6

- 4

- 2

0

2

4

6

1 2 3 4 5 6 7 8 9 10

Err

or

rate

(%

)

Design Time Energy Estimation (3/3)

Communication energy cost for a component For each target host, mt, mr, ct, and cr values should be avail

able for arbitrary BWs bt and br bytes/sec.

If available BWs are reduced to bt /2 and br /2 bytes/sec,

t t t t

r r r r

E m d c

E m d c

2

2

t t t t

r r r r

E m d c

E m d c

Transmission energy estimation on an iPAQ with 240 KB/sec BW and no communication errors

1.8546 0.015t tE d

Runtime Energy Estimation

0

20

40

60

80

100

120

140

10 20 50 100 200

Size of Data (KB)

Energ

y (J

oule

)

Actual240 KB/sec120 KB/sec

DBClient

iPAQ (host A)

Power Supply

Digital multimeter

Data CollectionComputer

Wirelessrouter

IBM X22 laptop(host B)

Desktop server(host C)

FTPClient

IDEA

LZW

DBServer

IDEA

FTPServer

IDEA

LZW

0

20

40

60

80

100

120

140

1.5 3.6 5.6 9.8 15.1

Frequency (times/sec)

Energ

y (J

oule

)

Actual240 KB/sec120 KB/sec

Conclusion

Suggested the framework for estimating the energy consumption of Java-based systems

Modeling the system energy consumption at the component’s level

Framework is applicable both during system construction time and during runtime

Showed very good precision on the whole (within 5% of actual energy consumption)

Plan to emulate various communication failures using emulation tools (e.g., Dummynet)