Revert "[flutter_driver] Add SceneDisplayLag stats to timeline summary (#54218)" (#54480)

This reverts commit ce92333bf7.

dev/devicelab/lib/tasks/perf_tests.dart

@@ -189,6 +189,7 @@ TaskFunction createColorFilterAndFadePerfTest() {
   ).run;
 }
 
+
 /// Measure application startup performance.
 class StartupTest {
   const StartupTest(this.testDirectory, { this.reportMetrics = true });
@@ -280,9 +281,6 @@ class PerfTest {
         'worst_frame_rasterizer_time_millis',
         '90th_percentile_frame_rasterizer_time_millis',
         '99th_percentile_frame_rasterizer_time_millis',
-        'average_vsync_transitions_missed',
-        '90th_percentile_vsync_transitions_missed',
-        '99th_percentile_vsync_transitions_missed',
         if (needsMeasureCpuGPu) 'cpu_percentage',
         if (needsMeasureCpuGPu) 'gpu_percentage',
       ]);

packages/flutter_driver/lib/src/driver/scene_display_lag_summarizer.dart

@@ -1,80 +0,0 @@
-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'timeline.dart';
-
-/// Key for SceneDisplayLag timeline events.
-const String kSceneDisplayLagEvent = 'SceneDisplayLag';
-
-const String _kVsyncTransitionsMissed = 'vsync_transitions_missed';
-
-/// Returns the [p]-th percentile element from the [doubles].
-///
-/// Note: [doubles] will be sorted.
-double findPercentile(List<double> doubles, double p) {
-  assert(doubles.isNotEmpty);
-  doubles.sort();
-  return doubles[((doubles.length - 1) * (p / 100)).round()];
-}
-
-/// Summarizes [TimelineEvents]s corresponding to [kSceneDisplayLagEvent] events.
-///
-/// A sample event (some fields have been omitted for brewity):
-/// ```
-///     {
-///      "name": "SceneDisplayLag",
-///      "ts": 408920509340,
-///      "ph": "b", (this can be 'b' or 'e' for begin or end)
-///      "args": {
-///        "frame_target_time": "408920509340458",
-///        "current_frame_target_time": "408920542689291",
-///        "vsync_transitions_missed": "2"
-///      }
-///    },
-/// ```
-///
-/// `vsync_transitions_missed` corresponds to the elapsed number of frame budget
-/// durations between when the frame was scheduled to be displayed, i.e, the
-/// `frame_target_time` and the next vsync pulse timestamp, i.e, the
-/// `current_frame_target_time`.
-class SceneDisplayLagSummarizer {
-  /// Creates a SceneDisplayLagSummarizer given the timeline events.
-  SceneDisplayLagSummarizer(this.sceneDisplayLagEvents) {
-    for (final TimelineEvent event in sceneDisplayLagEvents) {
-      assert(event.name == kSceneDisplayLagEvent);
-    }
-  }
-
-  /// The scene display lag events.
-  final List<TimelineEvent> sceneDisplayLagEvents;
-
-  /// Computes the average of the `vsync_transitions_missed` over the lag events.
-  double computeAverageVsyncTransitionsMissed() {
-    if (sceneDisplayLagEvents.isEmpty) {
-      return 0;
-    }
-
-    final double total = sceneDisplayLagEvents
-        .map(_getVsyncTransitionsMissed)
-        .reduce((double a, double b) => a + b);
-    return total / sceneDisplayLagEvents.length;
-  }
-
-  /// The [percentile]-th percentile `vsync_transitions_missed` over the lag events.
-  double computePercentileVsyncTransitionsMissed(double percentile) {
-    if (sceneDisplayLagEvents.isEmpty) {
-      return 0;
-    }
-
-    final List<double> doubles =
-        sceneDisplayLagEvents.map(_getVsyncTransitionsMissed).toList();
-    return findPercentile(doubles, percentile);
-  }
-
-  double _getVsyncTransitionsMissed(TimelineEvent e) {
-    assert(e.name == kSceneDisplayLagEvent);
-    assert(e.arguments.containsKey(_kVsyncTransitionsMissed));
-    return (e.arguments[_kVsyncTransitionsMissed] as num).toDouble();
-  }
-}

packages/flutter_driver/lib/src/driver/timeline_summary.dart

@@ -10,7 +10,6 @@ import 'package:file/file.dart';
 import 'package:path/path.dart' as path;
 
 import 'common.dart';
-import 'scene_display_lag_summarizer.dart';
 import 'timeline.dart';
 
 const JsonEncoder _prettyEncoder = JsonEncoder.withIndent('  ');
@@ -86,8 +85,6 @@ class TimelineSummary {
 
   /// Encodes this summary as JSON.
   Map<String, dynamic> get summaryJson {
-    final SceneDisplayLagSummarizer sceneDisplayLagSummarizer = _sceneDisplayLagSummarizer();
-
     return <String, dynamic>{
       'average_frame_build_time_millis': computeAverageFrameBuildTimeMillis(),
       '90th_percentile_frame_build_time_millis': computePercentileFrameBuildTimeMillis(90.0),
@@ -108,10 +105,7 @@ class TimelineSummary {
         .toList(),
       'frame_begin_times': _extractBeginTimestamps('Frame')
         .map<int>((Duration duration) => duration.inMicroseconds)
-        .toList(),
+        .toList()
-      'average_vsync_transitions_missed': sceneDisplayLagSummarizer.computeAverageVsyncTransitionsMissed(),
-      '90th_percentile_vsync_transitions_missed': sceneDisplayLagSummarizer.computePercentileVsyncTransitionsMissed(90.0),
-      '99th_percentile_vsync_transitions_missed': sceneDisplayLagSummarizer.computePercentileVsyncTransitionsMissed(99.0)
     };
   }
 
@@ -214,7 +208,9 @@ class TimelineSummary {
       throw ArgumentError('durations is empty!');
     assert(percentile >= 0.0 && percentile <= 100.0);
     final List<double> doubles = durations.map<double>((Duration duration) => duration.inMicroseconds.toDouble() / 1000.0).toList();
-    return findPercentile(doubles, percentile);
+    doubles.sort();
+    return doubles[((doubles.length - 1) * (percentile / 100)).round()];
+
   }
 
   double _maxInMillis(Iterable<Duration> durations) {
@@ -225,8 +221,6 @@ class TimelineSummary {
         .reduce(math.max);
   }
 
-  SceneDisplayLagSummarizer _sceneDisplayLagSummarizer() => SceneDisplayLagSummarizer(_extractNamedEvents(kSceneDisplayLagEvent));
-
   List<Duration> _extractGpuRasterizerDrawDurations() => _extractBeginEndEvents('GPURasterizer::Draw');
 
   List<Duration> _extractFrameDurations() => _extractBeginEndEvents('Frame');

packages/flutter_driver/test/src/real_tests/timeline_summary_test.dart

@@ -7,7 +7,6 @@ import 'dart:convert' show json;
 import 'package:file/file.dart';
 import 'package:flutter_driver/flutter_driver.dart';
 import 'package:flutter_driver/src/driver/common.dart';
-import 'package:flutter_driver/src/driver/scene_display_lag_summarizer.dart';
 import 'package:path/path.dart' as path;
 
 import '../../common.dart';
@@ -45,24 +44,6 @@ void main() {
       'ts': timeStamp,
     };
 
-    Map<String, dynamic> lagBegin(int timeStamp, int vsyncsMissed) => <String, dynamic>{
-      'name': 'SceneDisplayLag',
-      'ph': 'b',
-      'ts': timeStamp,
-      'args': <String, int>{
-        'vsync_transitions_missed': vsyncsMissed
-      }
-    };
-
-    Map<String, dynamic> lagEnd(int timeStamp, int vsyncsMissed) => <String, dynamic>{
-      'name': 'SceneDisplayLag',
-      'ph': 'e',
-      'ts': timeStamp,
-      'args': <String, int>{
-        'vsync_transitions_missed': vsyncsMissed
-      }
-    };
-
     List<Map<String, dynamic>> rasterizeTimeSequenceInMillis(List<int> sequence) {
       final List<Map<String, dynamic>> result = <Map<String, dynamic>>[];
       int t = 0;
@@ -375,9 +356,6 @@ void main() {
             'frame_build_times': <int>[17000, 9000, 19000],
             'frame_rasterizer_times': <int>[18000, 10000, 20000],
             'frame_begin_times': <int>[0, 18000, 28000],
-            'average_vsync_transitions_missed': 0.0,
-            '90th_percentile_vsync_transitions_missed': 0.0,
-            '99th_percentile_vsync_transitions_missed': 0.0
           },
         );
       });
@@ -413,9 +391,6 @@ void main() {
           frameBegin(1000), frameEnd(18000),
           frameBegin(19000), frameEnd(28000),
           frameBegin(29000), frameEnd(48000),
-          lagBegin(1000, 4), lagEnd(2000, 4),
-          lagBegin(1200, 12), lagEnd(2400, 12),
-          lagBegin(4200, 8), lagEnd(9400, 8),
         ]).writeSummaryToFile('test', destinationDirectory: tempDir.path);
         final String written =
             await fs.file(path.join(tempDir.path, 'test.timeline_summary.json')).readAsString();
@@ -434,62 +409,8 @@ void main() {
           'frame_build_times': <int>[17000, 9000, 19000],
           'frame_rasterizer_times': <int>[18000, 10000, 20000],
           'frame_begin_times': <int>[0, 18000, 28000],
-          'average_vsync_transitions_missed': 8.0,
-          '90th_percentile_vsync_transitions_missed': 12.0,
-          '99th_percentile_vsync_transitions_missed': 12.0
         });
       });
     });
-
-    group('SceneDisplayLagSummarizer tests', () {
-      SceneDisplayLagSummarizer summarize(List<Map<String, dynamic>> traceEvents) {
-          final Timeline timeline = Timeline.fromJson(<String, dynamic>{
-          'traceEvents': traceEvents,
-          });
-          return SceneDisplayLagSummarizer(timeline.events);
-      }
-
-      test('average_vsyncs_missed', () async {
-        final SceneDisplayLagSummarizer summarizer = summarize(<Map<String, dynamic>>[
-          lagBegin(1000, 4), lagEnd(2000, 4),
-          lagBegin(1200, 12), lagEnd(2400, 12),
-          lagBegin(4200, 8), lagEnd(9400, 8),
-        ]);
-        expect(summarizer.computeAverageVsyncTransitionsMissed(), 8.0);
-      });
-
-      test('all stats are 0 for 0 missed transitions', () async {
-        final SceneDisplayLagSummarizer summarizer = summarize(<Map<String, dynamic>>[]);
-        expect(summarizer.computeAverageVsyncTransitionsMissed(), 0.0);
-        expect(summarizer.computePercentileVsyncTransitionsMissed(90.0), 0.0);
-        expect(summarizer.computePercentileVsyncTransitionsMissed(99.0), 0.0);
-      });
-
-      test('90th_percentile_vsyncs_missed', () async {
-        final SceneDisplayLagSummarizer summarizer = summarize(<Map<String, dynamic>>[
-          lagBegin(1000, 4), lagEnd(2000, 4),
-          lagBegin(1200, 12), lagEnd(2400, 12),
-          lagBegin(4200, 8), lagEnd(9400, 8),
-          lagBegin(6100, 14), lagEnd(11000, 14),
-          lagBegin(7100, 16), lagEnd(11500, 16),
-          lagBegin(7400, 11), lagEnd(13000, 11),
-          lagBegin(8200, 27), lagEnd(14100, 27),
-          lagBegin(8700, 7), lagEnd(14300, 7),
-          lagBegin(24200, 4187), lagEnd(39400, 4187),
-        ]);
-        expect(summarizer.computePercentileVsyncTransitionsMissed(90), 27.0);
-      });
-
-      test('99th_percentile_vsyncs_missed', () async {
-        final SceneDisplayLagSummarizer summarizer = summarize(<Map<String, dynamic>>[
-          lagBegin(1000, 4), lagEnd(2000, 4),
-          lagBegin(1200, 12), lagEnd(2400, 12),
-          lagBegin(4200, 8), lagEnd(9400, 8),
-          lagBegin(6100, 14), lagEnd(11000, 14),
-          lagBegin(24200, 4187), lagEnd(39400, 4187),
-        ]);
-        expect(summarizer.computePercentileVsyncTransitionsMissed(99), 4187.0);
-      });
-    });
   });
 }