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1Samsung Open Source Group
JerryScript
An ultra-lightweight JavaScript engine for the Internet of Things
Tilmann Scheller
Principal Compiler Engineer
t.scheller@samsung.com
Samsung Open Source Group
Samsung Research UK
FOSDEM 2017
Brussels, Belgium, February 4 – 5, 2017

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2Samsung Open Source Group
Overview
● Introduction
● Demo
● Questions

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Introduction

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What is JerryScript?
● A really lightweight JavaScript engine
● Has a base footprint of ~3KB of RAM
● Optimized for microcontrollers
● Originally developed from scratch by Samsung
● JerryScript is an open source project released under the
Apache License 2.0
● Actively developed on GitHub

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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

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6Samsung 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

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7Samsung Open Source Group
JerryScript
● Written in pure C99
● About 91KLOC
● Code size at 133KB when compiled with GCC in LTO
mode 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

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JerryScript Portability
● Extremely portable
● Self-contained
● Small C standard library
● Can run on bare-metal
● Supports the STM32F4, Arduino 101, FRDM-K64F,
Photon, ESP8266 (experimental) boards
● OS support: NuttX, Zephyr, mbed OS, RIOT
● Runs on Linux/macOS as well

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Target hardware
● Particle Photon board
● Cortex-M3 clocked at 120 MHz
● 128KB of RAM
● 1MB of flash memory
● Integrated Wi-Fi
● Small footprint (37mm x 20mm)

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Memory consumption/
Performance

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SunSpider 1.0.2 - Memory consumption
3d-cube
3d-raytrace
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 50 100 150 200 250 300 350 400
35
185
38
11
11
5
5
4
139
80
57
142
92
21
21
6
5
12
125
20
138
339
160
101
106
98
97
97
207
135
190
261
169
352
147
102
101
102
267
107
JerryScript 1.0
Duktape 1.5.1
Max RSS in KB (lower is better) Measured on a Raspberry Pi 2

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SunSpider 1.0.2 - Performance
3d-cube
3d-raytrace
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 1 2 3 4 5 6 7 8
0.94
1.11
0.59
2.38
1.08
0.58
0.85
1.01
1.8
0.38
1.11
0.73
0.7
0.87
0.47
1.33
0.73
0.58
2.06
1.39
1.01
1.62
1.23
2.19
1.65
1.51
1.71
7.4
2.88
1.13
1.76
1.44
1.33
3.08
1.64
2.56
2.69
0.83
4.18
4.53
JerryScript 1.0
Duktape 1.5.1
Execution time in seconds (lower is better) Measured on a Raspberry Pi 2

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Demo

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JerryScript 6LoWPAN Demo
● Multiplayer implementation of the classic Pong game
● Each device drives one LED matrix as a display
● Game implemented in JavaScript
● Running on Photon board/Raspberry Pi 2
● Low-power wireless communication via 6LoWPAN
● "AI" opponent running on the microcontroller

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JerryScript 6LoWPAN Demo
Raspberry Pi 2
(1GB RAM, 8GB Flash)
Pong
JerryScript
Linux
Particle Photon
(128KB RAM, 1MB Flash)
Pong
JerryScript
RIOT
USB Keypad
LED Matrix LED Matrix
I2C I2C
Switches via GPIO
6LoWPAN

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Thank you.
16Samsung Open Source Group

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17Samsung Open Source Group
Contact Information:
Tilmann Scheller
t.scheller@samsung.com
Samsung Open Source Group
Samsung Research UK