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b755641559
Recently the microbenchmarks were flakey, but from an older bug. Turns out, `LiveTestWidgetsFlutterBindingFramePolicy` is defaulted to `fadePointers` with this fun note: > This can result in additional frames being pumped beyond those that the test itself requests, which can cause differences in behavior Both `text_intrinsic_bench` and `build_bench` use a similar pattern: * Load stocks app * Open the menu * Switch to `benchmark` frame policy What happens, rarely, is that `LiveTestWidgetsFlutterBinding.pumpBenchmark()` will call (async) `handleBeginFrame` and `handleDrawFrame`. `handleDrawFrame` juggles a tri-state boolean (null, false, true). This boolean is only reset to `null` when handleDrawFrame is called back to back, say, from an extra frame that was scheduled. 1. Switch tri-state boolean to an enum, its easier to read 2. remove asserts that compile away in benchmarks (`--profile`) 3. use `Error.throwWithStackTrace` to keep stack traces. I've been running this test on device lab hardware for hundreds of runs and have not hit a failure yet. Fixes #150542 Fixes #150543 - throw stack!
68 lines
2.6 KiB
Dart
68 lines
2.6 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:flutter/material.dart';
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import 'package:flutter_test/flutter_test.dart';
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import 'package:stocks/main.dart' as stocks;
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import 'package:stocks/stock_data.dart' as stock_data;
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import '../common.dart';
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const Duration kBenchmarkTime = Duration(seconds: 15);
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Future<List<double>> runBuildBenchmark() async {
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assert(false, "Don't run benchmarks in debug mode! Use 'flutter run --release'.");
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stock_data.StockData.actuallyFetchData = false;
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// We control the framePolicy below to prevent us from scheduling frames in
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// the engine, so that the engine does not interfere with our timings.
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final LiveTestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as LiveTestWidgetsFlutterBinding;
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final Stopwatch watch = Stopwatch();
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int iterations = 0;
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final List<double> values = <double>[];
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await benchmarkWidgets((WidgetTester tester) async {
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stocks.main();
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await tester.pump(); // Start startup animation
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await tester.pump(const Duration(seconds: 1)); // Complete startup animation
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await tester.tapAt(const Offset(20.0, 40.0)); // Open drawer
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await tester.pump(); // Start drawer animation
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await tester.pumpAndSettle(const Duration(seconds: 1)); // Complete drawer animation
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final Element appState = tester.element(find.byType(stocks.StocksApp));
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binding.framePolicy = LiveTestWidgetsFlutterBindingFramePolicy.benchmark;
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Duration elapsed = Duration.zero;
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while (elapsed < kBenchmarkTime) {
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watch.reset();
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watch.start();
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appState.markNeedsBuild();
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// We don't use tester.pump() because we're trying to drive it in an
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// artificially high load to find out how much CPU each frame takes.
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// This differs from normal benchmarks which might look at how many
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// frames are missed, etc.
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// We use Timer.run to ensure there's a microtask flush in between
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// the two calls below.
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await tester.pumpBenchmark(Duration(milliseconds: iterations * 16));
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watch.stop();
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iterations += 1;
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elapsed += Duration(microseconds: watch.elapsedMicroseconds);
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values.add(watch.elapsedMicroseconds.toDouble());
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}
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});
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return values;
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}
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Future<void> execute() async {
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final BenchmarkResultPrinter printer = BenchmarkResultPrinter();
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printer.addResultStatistics(
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description: 'Stock build',
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values: await runBuildBenchmark(),
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unit: 'µs per iteration',
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name: 'stock_build_iteration',
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);
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printer.printToStdout();
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}
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