web_benchmarks

A benchmark harness for Flutter Web apps. Currently only supports running benchmarks in Chrome.

Writing a benchmark

An example benchmark can be found in testing/test_app/benchmark/web_benchmark_test.dart.

A web benchmark is made of two parts: a client and a server. The client is code that runs in the browser together with the benchmark code. The server serves the app's code and assets. Additionally, the server communicates with the browser to extract the performance traces.

Analyzing benchmark results

After running web benchmarks, you may want to analyze the results or compare with the results from other benchmark runs. The web_benchmarks package supports the following analysis operations:

• compute the delta between two benchmark results
• compute the average of a set of benchmark results

import 'dart:convert';
import 'dart:io';

import 'package:web_benchmarks/analysis.dart';

void main() {
  final BenchmarkResults baselineResults = _benchmarkResultsFromFile(
    '/path/to/benchmark_baseline.json',
  );
  final BenchmarkResults testResults1 = _benchmarkResultsFromFile(
    '/path/to/benchmark_test_1.json',
  );
  final BenchmarkResults testResults2 = _benchmarkResultsFromFile(
    '/path/to/benchmark_test_2.json',
  );

  // Compute the delta between [baselineResults] and [testResults1].
  final BenchmarkResults delta = computeDelta(baselineResults, testResults1);
  stdout.writeln(delta.toJson());

  // Compute the average of [testResults] and [testResults2].
  final BenchmarkResults average = computeAverage(<BenchmarkResults>[
    testResults1,
    testResults2,
  ]);
  stdout.writeln(average.toJson());
}

BenchmarkResults _benchmarkResultsFromFile(String path) {
  final file = File.fromUri(Uri.parse(path));
  final fileContentAsJson =
      jsonDecode(file.readAsStringSync()) as Map<String, Object?>;
  return BenchmarkResults.parse(fileContentAsJson);
}