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chromium / chromium / src / ae356d4826fe5338eae7edb87e358a7ccd2e3d49 / . / cc / metrics / average_lag_tracker_unittest.cc
blob: e4460b8b1c19dc4f88a1533deab573309569c439 [file] [log] [blame]
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]1// Copyright 2019 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]5#include "cc/metrics/average_lag_tracker.h"
6
7#include <memory>
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]8
9#include "base/test/metrics/histogram_tester.h"
10#include "testing/gmock/include/gmock/gmock.h"
11#include "testing/gtest/include/gtest/gtest.h"
12
13using base::Bucket;
14using testing::ElementsAre;
15
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]16namespace cc {
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]17namespace {
18
19class AverageLagTrackerTest : public testing::Test {
20 public:
21 AverageLagTrackerTest() { ResetHistograms(); }
22
23 void ResetHistograms() {
Peter Boströmf2381042019-08-27 00:25:03[diff] [blame]24 histogram_tester_ = std::make_unique<base::HistogramTester>();
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]25 }
26
27 const base::HistogramTester& histogram_tester() { return *histogram_tester_; }
28
29 void SetUp() override {
Joao Victor Almeidaae356d42021-07-06 16:24:34[diff] [blame^]30 average_lag_tracker_ = std::make_unique<AverageLagTracker>();
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]31 }
32
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]33 void SyntheticTouchScrollBegin(base::TimeTicks event_time,
34 base::TimeTicks frame_time,
35 float delta,
36 float predicted_delta = 0) {
37 AverageLagTracker::EventInfo event_info(
38 0, delta, predicted_delta != 0 ? predicted_delta : delta, event_time,
39 AverageLagTracker::EventType::ScrollBegin);
40 event_info.finish_timestamp = frame_time;
Joao Victor Almeidaae356d42021-07-06 16:24:34[diff] [blame^]41 average_lag_tracker_->AddScrollEventInFrame(event_info);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]42 }
43
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]44 void SyntheticTouchScrollUpdate(base::TimeTicks event_time,
45 base::TimeTicks frame_time,
46 float delta,
47 float predicted_delta = 0) {
48 AverageLagTracker::EventInfo event_info(
49 0, delta, predicted_delta != 0 ? predicted_delta : delta, event_time,
50 AverageLagTracker::EventType::ScrollUpdate);
51 event_info.finish_timestamp = frame_time;
Joao Victor Almeidaae356d42021-07-06 16:24:34[diff] [blame^]52 average_lag_tracker_->AddScrollEventInFrame(event_info);
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]53 }
54
55 void CheckScrollBeginHistograms(int bucket_value, int count) {
56 EXPECT_THAT(histogram_tester().GetAllSamples(
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]57 "Event.Latency.ScrollBegin.Touch.AverageLagPresentation"),
58 ElementsAre(Bucket(bucket_value, count)));
59 }
60
61 void CheckScrollUpdateHistograms(int bucket_value, int count) {
62 EXPECT_THAT(histogram_tester().GetAllSamples(
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]63 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation"),
64 ElementsAre(Bucket(bucket_value, count)));
65 }
66
67 void CheckPredictionPositiveHistograms(int bucket_value, int count) {
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]68 EXPECT_THAT(histogram_tester().GetAllSamples(
69 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation."
70 "PredictionPositive"),
71 ElementsAre(Bucket(bucket_value, count)));
72 }
73
74 void CheckPredictionNegativeHistograms(int bucket_value, int count) {
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]75 EXPECT_THAT(histogram_tester().GetAllSamples(
76 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation."
77 "PredictionNegative"),
78 ElementsAre(Bucket(bucket_value, count)));
79 }
80
81 void CheckScrollUpdateHistogramsTotalCount(int count) {
82 histogram_tester().ExpectTotalCount(
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]83 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation", count);
84 }
85
86 void CheckPredictionPositiveHistogramsTotalCount(int count) {
87 histogram_tester().ExpectTotalCount(
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]88 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation."
89 "PredictionPositive",
90 count);
91 }
92
93 void CheckPredictionNegativeHistogramsTotalCount(int count) {
94 histogram_tester().ExpectTotalCount(
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]95 "Event.Latency.ScrollUpdate.Touch.AverageLagPresentation."
96 "PredictionNegative",
97 count);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]98 }
99
100 protected:
Joao Victor Almeidaae356d42021-07-06 16:24:34[diff] [blame^]101 std::unique_ptr<AverageLagTracker> average_lag_tracker_;
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]102
103 std::unique_ptr<base::HistogramTester> histogram_tester_;
104};
105
106base::TimeTicks MillisecondsToTimeTicks(float t_ms) {
107 return base::TimeTicks() + base::TimeDelta::FromMilliseconds(t_ms);
108}
109
110// Simulate a simple situation that events at every 10ms and start at t=15ms,
111// frame swaps at every 10ms too and start at t=20ms and test we record one
112// UMA for ScrollUpdate in one second.
113TEST_F(AverageLagTrackerTest, OneSecondInterval) {
114 base::TimeTicks event_time =
115 base::TimeTicks() + base::TimeDelta::FromMilliseconds(5);
116 base::TimeTicks frame_time =
117 base::TimeTicks() + base::TimeDelta::FromMilliseconds(10);
118 float scroll_delta = 10;
119
120 // ScrollBegin
121 event_time += base::TimeDelta::FromMilliseconds(10); // 15ms
122 frame_time += base::TimeDelta::FromMilliseconds(10); // 20ms
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]123 SyntheticTouchScrollBegin(event_time, frame_time, scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]124
125 // Send 101 ScrollUpdate events to verify that there is 1 AverageLag record
126 // per 1 second.
127 const int kUpdates = 101;
128 for (int i = 0; i < kUpdates; i++) {
129 event_time += base::TimeDelta::FromMilliseconds(10);
130 frame_time += base::TimeDelta::FromMilliseconds(10);
131 // First 50 has positive delta, others negetive delta.
132 const int sign = (i < kUpdates / 2) ? 1 : -1;
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]133 SyntheticTouchScrollUpdate(event_time, frame_time, sign * scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]134 }
135
136 // ScrollBegin report_time is at 20ms, so the next ScrollUpdate report_time is
137 // at 1020ms. The last event_time that finish this report should be later than
138 // 1020ms.
139 EXPECT_EQ(event_time,
140 base::TimeTicks() + base::TimeDelta::FromMilliseconds(1025));
141 EXPECT_EQ(frame_time,
142 base::TimeTicks() + base::TimeDelta::FromMilliseconds(1030));
143
144 // ScrollBegin AverageLag are the area between the event original component
145 // (time=15ms, delta=10px) to the frame swap time (time=20ms, expect finger
146 // position at delta=15px). The AverageLag scaled to 1 second is
147 // (0.5*(10px+15px)*5ms)/5ms = 12.5px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]148 CheckScrollBeginHistograms(12, 1);
149
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]150 // This ScrollUpdate AverageLag are calculated as the finger uniformly scroll
151 // 10px each frame. For scroll up/down frame, the Lag at the last frame swap
152 // is 5px, and Lag at this frame swap is 15px. For the one changing direction,
153 // the Lag is from 5 to 10 and down to 5 again. So total LagArea is 99 * 100,
154 // plus 75. the AverageLag in 1 second is 9.975px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]155 CheckScrollUpdateHistograms(9, 1);
156 CheckPredictionPositiveHistograms(0, 1);
157 CheckPredictionNegativeHistogramsTotalCount(0);
158
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]159 ResetHistograms();
160
161 // Send another ScrollBegin to end the unfinished ScrollUpdate report.
162 event_time += base::TimeDelta::FromMilliseconds(10);
163 frame_time += base::TimeDelta::FromMilliseconds(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]164 SyntheticTouchScrollBegin(event_time, frame_time, scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]165
166 // The last ScrollUpdate's lag is 8.75px and truncated to 8.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]167 CheckScrollUpdateHistograms(8, 1);
168 CheckPredictionPositiveHistograms(0, 1);
169 CheckPredictionNegativeHistogramsTotalCount(0);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]170}
171
172// Test the case that event's frame swap time is later than next event's
173// creation time. (i.e, event at t=10ms will be dispatch at t=30ms, while next
174// event is at t=20ms).
175TEST_F(AverageLagTrackerTest, LargerLatency) {
176 base::TimeTicks event_time = MillisecondsToTimeTicks(10);
177 base::TimeTicks frame_time =
178 event_time + base::TimeDelta::FromMilliseconds(20);
179 float scroll_delta = 10;
180
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]181 SyntheticTouchScrollBegin(event_time, frame_time, scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]182
183 // Send 2 ScrollUpdate. The second one will record AverageLag.ScrollBegin as
184 // it's event_time is larger or equal to ScrollBegin's frame_time.
185 for (int i = 0; i < 2; i++) {
186 event_time += base::TimeDelta::FromMilliseconds(10);
187 frame_time = event_time + base::TimeDelta::FromMilliseconds(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]188 SyntheticTouchScrollUpdate(event_time, frame_time, scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]189 }
190
191 // ScrollBegin AveragLag are from t=10ms to t=30ms, with absolute scroll
192 // position from 10 to 30. The AverageLag should be:
193 // (0.5*(10px + 30px)*20ms/20ms) = 20px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]194 CheckScrollBeginHistograms(20, 1);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]195
196 // Another ScrollBegin to flush unfinished frames.
197 // event_time doesn't matter here because the previous frames' lag are
198 // compute from their frame_time.
199 event_time = MillisecondsToTimeTicks(1000);
200 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]201 SyntheticTouchScrollBegin(event_time, frame_time, scroll_delta);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]202 // The to unfinished frames' lag are (finger_positon-rendered_position)*time,
203 // AverageLag is ((30px-10px)*10ms+(30px-20px)*10ms)/20ms = 15px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]204 CheckScrollUpdateHistograms(14, 1);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]205}
206
207// Test that multiple latency being flush in the same frame swap.
208TEST_F(AverageLagTrackerTest, TwoLatencyInfoInSameFrame) {
209 // ScrollBegin
210 base::TimeTicks event_time = MillisecondsToTimeTicks(10);
211 base::TimeTicks frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]212 SyntheticTouchScrollBegin(event_time, frame_time, -10 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]213
214 // ScrollUpdate with event_time >= ScrollBegin frame_time will generate
215 // a histogram for AverageLag.ScrollBegin.
216 event_time = MillisecondsToTimeTicks(20);
217 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]218 SyntheticTouchScrollUpdate(event_time, frame_time, -10 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]219
220 // Absolute position from -10 to -20. The AverageLag should be:
221 // (0.5*(10px + 20px)*10ms/10ms) = 15px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]222 CheckScrollBeginHistograms(14, 1);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]223
224 event_time = MillisecondsToTimeTicks(25);
225 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]226 SyntheticTouchScrollUpdate(event_time, frame_time, 5 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]227
228 // Another ScrollBegin to flush unfinished frames.
229 event_time = MillisecondsToTimeTicks(1000);
230 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]231 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]232
233 // The ScrollUpdates are at t=20ms, finger_pos=-20px, rendered_pos=-10px,
234 // at t=25ms, finger_pos=-15px, rendered_pos=-10px;
235 // To t=30ms both events get flush.
236 // AverageLag is (0.5*(10px+5px)*5ms + 5px*5ms)/10ms = 6.25px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]237 CheckScrollUpdateHistograms(6, 1);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]238}
239
240// Test the case that switching direction causes lag at current frame
241// time and previous frame time are in different direction.
242TEST_F(AverageLagTrackerTest, ChangeDirectionInFrame) {
243 // ScrollBegin
244 base::TimeTicks event_time = MillisecondsToTimeTicks(10);
245 base::TimeTicks frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]246 SyntheticTouchScrollBegin(event_time, frame_time, 10 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]247
248 // At t=20, lag = 10px.
249 event_time = MillisecondsToTimeTicks(20);
250 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]251 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]252
253 // At t=30, lag = -10px.
254 event_time = MillisecondsToTimeTicks(30);
255 frame_time = MillisecondsToTimeTicks(40);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]256 SyntheticTouchScrollUpdate(event_time, frame_time, -20 /* scroll_delta */);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]257
258 // Another ScrollBegin to flush unfinished frames.
259 event_time = MillisecondsToTimeTicks(1000);
260 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]261 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]262
263 // From t=20 to t=30, lag_area=2*(0.5*10px*5ms)=50px*ms.
264 // From t=30 to t=40, lag_area=20px*10ms=200px*ms
265 // AverageLag = (50+200)/20 = 12.5px.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]266 CheckScrollUpdateHistograms(12, 1);
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]267}
268
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]269// A simple case without scroll prediction to compare with the two with
270// prediction cases below.
271TEST_F(AverageLagTrackerTest, NoScrollPrediction) {
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]272 // ScrollBegin, at t=5, finger_pos=5px.
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]273 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
274 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]275 SyntheticTouchScrollBegin(event_time, frame_time, 5 /* scroll_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]276
277 // ScrollUpdate, at t=15, finger_pos=15px.
278 event_time = MillisecondsToTimeTicks(15);
279 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]280 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]281
282 // ScrollUpdate, at t=25, finger_pos=25px.
283 event_time = MillisecondsToTimeTicks(25);
284 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]285 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]286
287 // Another ScrollBegin to flush unfinished frames.
288 event_time = MillisecondsToTimeTicks(1000);
289 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]290 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]291
292 // Prediction hasn't take affect on ScrollBegin so it'll stay the same.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]293 CheckScrollBeginHistograms(7, 1);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]294 // At t=10, finger_pos = 10px, rendered_pos = 5px.
295 // At t=20, finger_pos = 20px, rendered_pos = 15px.
296 // At t=30, finger_pos = 25px, rendered_pos = 25px.
297 // AverageLag = ((5px+15px)*10ms/2 + (5px+10px)*5ms/2 + 10px*5ms)/20ms
298 // = 9.375
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]299 CheckScrollUpdateHistograms(9, 1);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]300}
301
302// Test AverageLag with perfect scroll prediction.
303TEST_F(AverageLagTrackerTest, ScrollPrediction) {
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]304 // ScrollBegin, at t=5, finger_pos=5px.
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]305 // Predict frame_time=10, predicted_pos = 10px.
306 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
307 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]308 SyntheticTouchScrollBegin(event_time, frame_time, 5 /* scroll_delta */,
309 10 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]310
311 // ScrollUpdate, at t=15, finger_pos=15px.
312 // Predict frame_time=20, predicted_pos = 20px.
313 event_time = MillisecondsToTimeTicks(15);
314 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]315 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
316 10 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]317
318 // ScrollUpdate, at t=25, finger_pos=25px.
319 // Predict frame_time=30, predicted_pos = 30px.
320 event_time = MillisecondsToTimeTicks(25);
321 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]322 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
323 10 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]324
325 // Another ScrollBegin to flush unfinished frames.
326 event_time = MillisecondsToTimeTicks(1000);
327 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]328 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]329
330 // Prediction hasn't take affect on ScrollBegin so it'll stay the same.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]331 CheckScrollBeginHistograms(7, 1);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]332 // At t=10, finger_pos = 10px, rendered_pos = 10px.
333 // At t=20, finger_pos = 20px, rendered_pos = 20px.
334 // At t=30, finger_pos = 25px, rendered_pos = 30px.
335 // AverageLag = ((0px+10px)*10ms/2 + (0px+5px)*10ms/2 + 5px*5ms)/20ms
336 // = 4.375px
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]337 // AverageLag (w/o prediction)
338 // ((5px+15px)*10ms/2 + (5px+10px)*5ms/2 + 10px*5ms)/20ms
339 // = 9.375px
340 // Positive effect of prediction = 5px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]341 CheckScrollUpdateHistograms(4, 1);
342 CheckPredictionPositiveHistograms(5, 1);
343 CheckPredictionNegativeHistogramsTotalCount(0);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]344}
345
346// Test AverageLag with imperfect scroll prediction.
347TEST_F(AverageLagTrackerTest, ImperfectScrollPrediction) {
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]348 // ScrollBegin, at t=5, finger_pos=5px.
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]349 // Predict frame_time=10, predicted_pos(over) = 12px.
350 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
351 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]352 SyntheticTouchScrollBegin(event_time, frame_time, 5 /* scroll_delta */,
353 12 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]354
355 // ScrollUpdate, at t=15, finger_pos=15px.
356 // Predict frame_time=20, predicted_pos(under) = 17px.
357 event_time = MillisecondsToTimeTicks(15);
358 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]359 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
360 5 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]361
362 // ScrollUpdate, at t=25, finger_pos=25px.
363 // Predict frame_time=30, predicted_pos(over) = 31px.
364 event_time = MillisecondsToTimeTicks(25);
365 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]366 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
367 14 /* predicted_delta */);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]368
369 // Another ScrollBegin to flush unfinished frames.
370 event_time = MillisecondsToTimeTicks(1000);
371 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]372 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]373
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]374 CheckScrollBeginHistograms(7, 1);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]375 // AverageLag = ((2px*2ms/2+8px*8ms/2)+ ((3px+8px)*5ms/2+8px*5ms))/20ms
376 // = 5.075px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]377 CheckScrollUpdateHistograms(5, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]378 // AverageLag (w/o prediction =
379 // ((5px+15px)*10ms/2 + (5px+10px)*5ms/2 + 10px*5ms)/20ms
380 // = 9.375px
381 // Positive effect of prediction = 4.3px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]382 CheckPredictionPositiveHistograms(4, 1);
383 CheckPredictionNegativeHistogramsTotalCount(0);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]384}
385
386TEST_F(AverageLagTrackerTest, NegativePredictionEffect) {
387 // ScrollBegin, at t=5, finger_pos=5px.
388 // Predict frame_time=10, predicted_pos(over) = 20px.
389 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
390 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]391 SyntheticTouchScrollBegin(event_time, frame_time, 5 /* scroll_delta */,
392 20 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]393
394 // ScrollUpdate, at t=15, finger_pos=15px.
395 // Predict frame_time=20, predicted_pos(over) = 60px.
396 event_time = MillisecondsToTimeTicks(15);
397 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]398 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
399 40 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]400
401 // ScrollUpdate, at t=25, finger_pos=25px.
402 // Predict frame_time=30, predicted_pos(over) = 60px.
403 event_time = MillisecondsToTimeTicks(25);
404 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]405 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
406 0 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]407
408 // Another ScrollBegin to flush unfinished frames.
409 event_time = MillisecondsToTimeTicks(1000);
410 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]411 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]412
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]413 CheckScrollBeginHistograms(7, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]414 // AverageLag = ((10px+0px)*10ms/2)+ ((40px+35px)*5ms/2+35px*5ms))/20ms
415 // = 20.625px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]416 CheckScrollUpdateHistograms(20, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]417 // AverageLag (w/o prediction =
418 // ((5px+15px)*10ms/2 + (5px+10px)*5ms/2 + 10px*5ms)/20ms
419 // = 9.375px
420 // Negative effect of prediction = 11.25
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]421 CheckPredictionPositiveHistogramsTotalCount(0);
422 CheckPredictionNegativeHistograms(11, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]423}
424
425TEST_F(AverageLagTrackerTest, NoPredictionEffect) {
426 // ScrollBegin, at t=5, finger_pos=5px.
427 // Predict frame_time=10, predicted_pos(over) = 25px.
428 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
429 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]430 SyntheticTouchScrollBegin(event_time, frame_time, 5 /* scroll_delta */,
431 25 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]432
433 // ScrollUpdate, at t=15, finger_pos=15px.
434 // Predict frame_time=20, predicted_pos(over) = 32px.
435 event_time = MillisecondsToTimeTicks(15);
436 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]437 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
438 7 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]439
440 // ScrollUpdate, at t=25, finger_pos=25px.
441 // Predict frame_time=30, predicted_pos(over) = 37px.
442 event_time = MillisecondsToTimeTicks(25);
443 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]444 SyntheticTouchScrollUpdate(event_time, frame_time, 10 /* scroll_delta */,
445 5 /* predicted_delta */);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]446
447 // Another ScrollBegin to flush unfinished frames.
448 event_time = MillisecondsToTimeTicks(1000);
449 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]450 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]451
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]452 CheckScrollBeginHistograms(7, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]453 // AverageLag = ((15px+5px)*10ms/2 + (12px+7px)*5ms/2 + 7px*5ms)/20ms
454 // = 9.125px
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]455 CheckScrollUpdateHistograms(9, 1);
Daniel Libbyf7cf77382019-05-06 19:23:44[diff] [blame]456 // AverageLag (w/o prediction) =
457 // ((5px+15px)*10ms/2 + (5px+10px)*5ms/2 + 10px*5ms)/20ms
458 // = 9.375px
459 // Prediction slightly positive, we should see a 0 bucket in
460 // PredictionPositive UMA
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]461 CheckPredictionPositiveHistograms(0, 1);
462 CheckPredictionNegativeHistogramsTotalCount(0);
Ella Ge7d1d3be202019-04-08 16:47:59[diff] [blame]463}
464
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]465// Tests that when an event arrives out-of-order, the average lag tracker
466// properly ignores it.
467TEST_F(AverageLagTrackerTest, EventOutOfOrder) {
468 base::TimeTicks event_time = MillisecondsToTimeTicks(5);
469 base::TimeTicks frame_time = MillisecondsToTimeTicks(10);
470 float scroll_delta = 5.f;
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]471 SyntheticTouchScrollBegin(event_time, frame_time, scroll_delta);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]472
473 event_time = MillisecondsToTimeTicks(15);
474 frame_time = MillisecondsToTimeTicks(20);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]475 SyntheticTouchScrollUpdate(event_time, frame_time, scroll_delta);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]476
477 event_time = MillisecondsToTimeTicks(25);
478 frame_time = MillisecondsToTimeTicks(30);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]479 SyntheticTouchScrollUpdate(event_time, frame_time, scroll_delta);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]480
481 // A ScrollBegin to flush unfinished frames.
482 event_time = MillisecondsToTimeTicks(1000);
483 frame_time = MillisecondsToTimeTicks(1000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]484 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]485
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]486 CheckScrollUpdateHistogramsTotalCount(1);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]487
488 // Send an event whose timestamp is earlier than the most recent event,
489 // representing an event that gets process out of order.
490 base::TimeTicks earlier_event_time = MillisecondsToTimeTicks(15);
491 frame_time = MillisecondsToTimeTicks(1010);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]492 SyntheticTouchScrollUpdate(earlier_event_time, frame_time, scroll_delta);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]493
494 // Another ScrollBegin to flush unfinished frames.
495 event_time = MillisecondsToTimeTicks(2000);
496 frame_time = MillisecondsToTimeTicks(2000);
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]497 SyntheticTouchScrollBegin(event_time, frame_time, 0);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]498
499 // Ensure that the event was ignored.
Joao Victor Almeida0b3c5a92020-07-07 21:04:43[diff] [blame]500 CheckScrollUpdateHistogramsTotalCount(1);
Matt Amert9da83c32019-11-06 06:04:31[diff] [blame]501}
502
Ella Ge792e4f12019-04-05 17:32:15[diff] [blame]503} // namespace
Joao Victor Almeida917ce172020-07-07 20:56:12[diff] [blame]504} // namespace cc