declarativesensor networks

David ChuComputer Science DivisionEECS DepartmentUC Berkeley

DBLunchUC Berkeley

2 March 2007

context

Leach's Storm Petrel

Sensor Networks 10’s – 100’s – 1000’s – 10,000’s

contextSensor Networks early experiences

motivation

programming sensor networks is difficult!

building entire sensor systems is even harder!!

inspiration

data management network design

s e n s o r n e t w o r k s

inspiration : data management• declarative is widely used in data

management– relational databases– spreadsheets– abstract “what” from “how”

• (Sensor-Network-As-Database)

inspiration : network design• declarative is new idea in networking

– compact– flexible– analyzable, optimizable– Internet Routing, Overlays built declaratively

• (the P2 project)

inspiration

data management network design

s e n s o r n e t w o r k s

( DSN )

what we did

• adapted declarative language

• built compiler & runtime for sensornets

• wrote declarative examples

… from original Trickle paper … DSN specification

10x6 topology

30x2 topology

agenda

1. language overview

2. declarative sensornet examples

3. system architecture

4. feasibility assessment

5. application to landslide detection

brief language overview

Rule2:

Fact:

Rule1:

join don’t care

Built-ins:

implies

a full example : tree

D

S

C

D

Z

C2

SC1

and others…

geographic routing* tracking localization link estimator

*fallback routing not shown

arch : compiler

Network support

Generated nesC code

store(…) :- prod(…), cons(…). … path(…) :- link(…), dest(…).…

Binary Image

Snlog Compiler/OptimizerSnlog

Program

GenericPredicateTemplate……

nesCTemplates

nesC Backend

Execution Planner

Snlog Frontend

nesC Compiler

Built-in Predicates

Type system

Database Operators

RuntimeComponents

RuntimeTemplate……

DSN Runtime Support

arch : runtime

the network

Join Join Proj

tupleready

Join AggProj Sel

table(compiler generated)

builtin(user’s library)

database operators(compiler’s library)

push interfaces

pull interfaces

thread of control

event signal

Sel Ag Proj

… … …

… …

… …

runtimedaemon

mac daemon

tupleready

tuplereadysendready

tupleready sendready

implementation challenges• predictable execution

→ dynamic vs. static allocation

• memory constraints→ memory footprint optimizations

no temporary tables, join/agg operator choice

• asynchrony→ rule-level atomicity

priorities

evaluation

evaluating tree-collection

messages sent

hop-counts

(similar performance)

lines of code

compiled size

TelosB mote code space = 48KB, data space = 10KB

VLDB 2006 demo

current efforts

• energy-based optimization– send or store

• language semantics clarity– non-monotonic logic

conclusion

• sensor networks→ data + communication

• several examples of functional programs

• feasible for today’s hardware platforms

• preparing for landslide deployment

thanks

collaborators

Joe Hellerstein, Scott Shenker, Ion Stoica

Arsalan Tavakoli, Lucian Popa

Phil Levis