dart-js-improvements

This package helps benchmark and identify areas for improvement in Dart2JS.

Specifically, we are tracking:

• Code size of the final .dart.js binary.
• Cold (non-JITd) startup cost of running .dart.js (affecting TTI).
  • Not including impact to download speed on low-end devices/networks.

Results

The following was run as an example only on the following machine:

• MacBook Pro 15-Inch 2016
• 2.9 GHz Intel Core i7
• 16 GB 2133 MHz LPDDR3

With the following tools:

• Dart VM/SDK 2.0.0-dev.6.0
• NodeJS v8.9.0

None of the benchmarks instrument threading (single-threaded nodeJS).

To run the benchmarks yourself:

$ git clone https://github.com/matanlurey/dart-js-improvements.git
$ pub build benchmark 

And then for the code-size, run:

$ pub run jsbench

And for runtime speed, run:

$ dart tool/patch.dart
$ dart tool/sample.dart

The following used a sample-size of 100.

RTTI

We run benchmarks instantiating 1000 classes that may store RTTI.

with_runtime_type.dart.js

• Size: 162kB
• Mean: 203.25ms
• Median: 199ms

without_runtime_type.dart.js

• Size: 49.2kB
• Mean: 132.75ms
• Median: 133ms

Enums

We run benchmarks instantiating 1000 enums with 5 fields each.

class_enums.dart.js

• Size: 205kB
• Mean: 134.39ms
• Median: 132ms

int_enums.dart.js

• Size: 10.3kB
• Mean: 61.97ms
• Median: 61ms

lang_enums.dart.js

• Size: 264kB
• Mean: 132.09ms
• Median: 131ms

Streams

We run benchmarks creating 1000 stream-likes and listening to them.

listenables.dart.js

• Size: 160kB
• Mean: 129.49ms
• Median: 129ms

zoned_listenables.dart.js

• Size: 167kB
• Mean: 131.4ms
• Median: 131ms

sdk_streams.dart.js

• Size: 204kB
• Mean: 139.23ms
• Median: 138ms

Collections

We create 1000 lists or arrays, add items, use some common methods.

NOTE: Code-size is not included here, since the JS code is not minified.

dart_array.dart.js

• Mean: 145.86ms
• Median: 121ms

js_array.dart.js

Using eval(), which has overhead on top of plain JavaScript.

• Mean: 122.94ms
• Median: 121ms

dart_object.dart.js

• Mean: 160.8ms
• Median: 152ms

js_object.dart.js

• Mean: 148.58ms
• Median: 147ms

JSON

Decodes+encodes an almost 13mb representative JSON data set.

NOTE: Code-size is not included here as it is not significantly different.

dart_json.dart.js

• Mean: 957.56ms
• Median: 948ms

js_json.dart.js

• Mean: 301.96ms
• Median: 297ms