This document discusses IoT.js, a lightweight version of Node.js designed for resource-constrained devices. It introduces JerryScript, a lightweight JavaScript engine developed by Samsung with a footprint of only 10KB that IoT.js runs on. The document outlines the goals and architecture of IoT.js, provides performance comparisons with other JavaScript engines, and demonstrates IoT.js running games like Tetris and Pong across devices with different capabilities. Future plans include further optimizations and adding more modules to expand IoT.js capabilities.

1. 1Samsung Open Source Group
Introduction to IoT.js
Tilmann Scheller
Principal Compiler Engineer
t.scheller@samsung.com
Samsung Open Source Group
Samsung Research UK
OpenIoT Summit 2016
San Diego, USA, April 4 – 6, 2016

2. 2Samsung Open Source Group
Overview
● Introduction
● JerryScript
● IoT.js
● Memory consumption/Performance
● Demo
● Future work
● Summary

3. 3Samsung Open Source Group
Introduction

4. 4Samsung Open Source Group
What is IoT.js?
● A lightweight version of Node.js
● Attempt to bring the success of Node.js to the embedded
world
● Retains backwards compatibility with Node.js as much as
possible
● Runs on top of JerryScript

5. 5Samsung Open Source Group
IoT Hardware
http://postscapes.com/internet-of-things-hardware

6. 6Samsung Open Source Group
What is JerryScript?
● A really lightweight JavaScript engine
● Has a base footprint of 10KB of RAM
● Optimized for microcontrollers
● Developed from scratch by Samsung

7. 7Samsung Open Source Group
Why JavaScript on microcontrollers?
● There's a huge pool of JavaScript developers
● Opens up the possibility for web developers to easily write
software for embedded devices
● Performance overhead of JavaScript less of an issue for
control tasks
● Increased productivity, shorter time to market
● Ability to load code dynamically over the network
● Security: Executing JavaScript code is safer than executing
arbitrary native code

8. 8Samsung Open Source Group
Open source
● Actively developed on GitHub
● JerryScript and IoT.js are both open source released
under the Apache 2.0 license
● Building up a community around IoT.js/JerryScript

9. 9Samsung Open Source Group
JerryScript

10. 10Samsung Open Source Group
JerryScript History
● Development started in June 2014
● Released as open source in June 2015
● JerryScript passed 100% of the test262 conformance test
suite in August 2015
● Rewritten compact byte code implementation landed in
January 2016
● Current focus on performance optimization

11. 11Samsung Open Source Group
JerryScript
● Heavily optimized for a low memory footprint
● Interpreter-only
● Compact object representation
● Compressed pointers
● No AST, directly creating byte code
● Compact byte code heavily optimized for low memory
consumption

12. 12Samsung Open Source Group
JerryScript Portability
● Extremely portable
● Self-contained
● Small C library
● Can run bare-metal
● Supports the STM32F4, ESP8266 boards
● Runs on Linux/OS X as well

13. 13Samsung Open Source Group
JerryScript
● Written in C99
● About 74KLOC
● Code size ~190KB when compiled with GCC LTO for
ARM Thumb-2
● Implements the entire ECMAScript 5.1 standard, passes
100% of the test262 conformance test suite
● C API for embedding JerryScript
● Byte code snapshot feature

14. 14Samsung Open Source Group
JerryScript C API

15. 15Samsung Open Source Group
JerryScript C API

16. 16Samsung Open Source Group
IoT.js

17. 17Samsung Open Source Group
IoT.js
● Lightweight version of Node.js
● Focus on resource-constrained devices
● Tries to retain backwards compatibility
● Mostly written in JavaScript

18. 18Samsung Open Source Group
IoT.js Architecture

19. 19Samsung Open Source Group
IoT.js Modules
● Assert
● Buffer
● DNS
● Events
● File System
● HTTP
● Net
● Modules
● Process
● Stream
● Timers
● GPIO

20. 20Samsung Open Source Group
Target hardware
● STM32F4 developer board
● Cortex-M4F clocked at 168 MHz
● 192KB of RAM
● 1MB of flash memory

21. 21Samsung Open Source Group
NuttX
● Real-time operating system
● Open source (BSD license)
● Scales from 8-bit microcontrollers to 32-bit
microcontrollers
● Supports the STM32F4 developer board

22. 22Samsung Open Source Group
libtuv
● libuv - Support library for asynchronous I/O
● libtuv - Stripped down version of Libuv
● Runs on NuttX and Linux
● Experimental support for mbed OS

23. 23Samsung Open Source Group
Memory consumption/
Performance

24. 24Samsung Open Source Group
IoT.js - Memory consumption
Measured on a Raspberry Pi 2
Test name IoT.js Node.js
require('http') 40KB 6.70MB
test_httpserver.js 80KB 8.63MB

25. 25Samsung Open Source Group
SunSpider 1.0.2 - Memory consumption
3d-cube
access-binary-trees
access-fannkuch
access-nbody
bitops-3bit-bits-in-byte
bitops-bits-in-byte
bitops-bitwise-and
bitops-nsieve-bits
controlflow-recursive
crypto-aes
crypto-md5
crypto-sha1
date-format-tofte
date-format-xparb
math-cordic
math-partial-sums
math-spectral-norm
string-base64
string-fasta
0 100 200 300 400 500 600 700
76
76
32
36
24
24
24
148
136
104
152
112
60
52
32
28
32
152
44
216
240
160
172
160
160
160
384
204
268
420
304
572
220
164
160
164
324
172
JerryScript
Duktape 1.4
Max RSS in KB (lower is better) Measured on a Raspberry Pi 2

26. 26Samsung Open Source Group
SunSpider 1.0.2 - Performance
3d-cube
access-binary-trees
access-fannkuch
access-nbody
bitops-3bit-bits-in-byte
bitops-bits-in-byte
bitops-bitwise-and
bitops-nsieve-bits
controlflow-recursive
crypto-aes
crypto-md5
crypto-sha1
date-format-tofte
date-format-xparb
math-cordic
math-partial-sums
math-spectral-norm
string-base64
string-fasta
0 2 4 6 8 10 12 14 16 18 20
2.54
1.36
7.38
2.81
1.62
2.39
3.27
17.88
0.95
3.36
3.29
2.07
2.09
0.83
2.83
1.57
1.46
5.08
3.21
1.44
1.78
3.4
2.23
2.42
2.73
10.75
4.52
1.51
2.58
2.08
1.93
4.64
2.23
3.62
3.73
1.13
5.95
6.46
JerryScript
Duktape 1.4
Execution time in seconds (lower is better) Measured on a Raspberry Pi 2

27. 27Samsung Open Source Group
ubench - Memory consumption
loop-sum
loop-empty-resolve
loop-empty
function-sum
function-missing-args
function-excess-args
function-emtpy
function-correct-args
function-closure
0 100 200 300 400 500 600
24
24
24
24
24
24
24
24
32
152
152
152
156
156
156
156
156
496
JerryScript
Duktape 1.4
Max RSS in KB (lower is better) Measured on a Raspberry Pi 2

28. 28Samsung Open Source Group
ubench - Performance
loop-sum
loop-empty-resolve
loop-empty
function-sum
function-missing-args
function-excess-args
function-emtpy
function-correct-args
function-closure
0 10 20 30 40 50 60 70 80 90
35.48
3.42
30.14
18.05
16.09
20.85
19.66
22.18
2.62
76.65
6.41
55.23
23.93
27.35
27.93
38.89
27.95
18.87
JerryScript
Duktape 1.4
Execution time in seconds (lower is better) Measured on a Raspberry Pi 2

29. 29Samsung Open Source Group
Demo

30. 30Samsung Open Source Group
Tetris Demo
● Implementation of the classic Tetris game
● Each device drives one LED matrix as display
● Implemented as a Node.js module
● Both devices are running exactly the same JavaScript
code

31. 31Samsung Open Source Group
Demo
Raspberry Pi 2
(1GB RAM, 8GB Flash)
Tetris
Node.js
V8
Linux
STM32F4 board
(192KB RAM, 1MB Flash)
Tetris
IoT.js
JerryScript
NuttX
USB Keypad
LED Matrix LED Matrix
I2C I2C
Switches via GPIO

32. 32Samsung Open Source Group
Tetris Demo
https://youtu.be/q4iBeOAC7XI

33. 33Samsung Open Source Group
Pong Demo
● Implementation of the classic Pong game
● Display shared across two devices
● Each device drives one LED matrix
● Implemented as a Node.js module
● "AI" oppenent running on the microcontroller

34. 34Samsung Open Source Group
Demo
Raspberry Pi 2
(1GB RAM, 8GB Flash)
Pong Client
Node.js
V8
Linux
STM32F4 board
(192KB RAM, 1MB Flash)
Pong Server
IoT.js
JerryScript
NuttX
Ethernet
USB Keypad
LED Matrix LED Matrix
I2C I2C

35. 35Samsung Open Source Group
Pong Demo

36. 36Samsung Open Source Group
Future work

37. 37Samsung Open Source Group
Future work
● Close performance gap between JerryScript and Duktape
● Further performance and memory optimizations
● Enhance JerryScript C API
● Add more IoT.js modules
● Package manager for IoT.js
● Support more devices

38. 38Samsung Open Source Group
Summary

39. 39Samsung Open Source Group
Summary
● Significantly lowers barrier of entry for JavaScript
development targeting heavily constrained embedded
devices
● Speeds up development
● Active community
● More information on http://www.jerryscript.net and
http://www.iotjs.net
● Looking for bug reports and feedback

40. Thank you.
40Samsung Open Source Group

41. 41Samsung Open Source Group
Contact Information:
Tilmann Scheller
t.scheller@samsung.com
Samsung Open Source Group
Samsung Research UK