def testDiscrepancyAnalytic(self):
"""Computes discrepancy for sample sets with known statistics."""
interval_multiplier = 100000
samples = []
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertEquals(d, 1.0)
samples = [0.5]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertEquals(round(d), 1.0)
samples = [0.0, 1.0]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertAlmostEquals(round(d, 2), 1.0)
samples = [0.5, 0.5, 0.5]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertAlmostEquals(d, 1.0)
samples = [1.0/8.0, 3.0/8.0, 5.0/8.0, 7.0/8.0]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertAlmostEquals(round(d, 2), 0.25)
samples = [0.0, 1.0/3.0, 2.0/3.0, 1.0]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertAlmostEquals(round(d, 2), 0.5)
samples = statistics.NormalizeSamples(samples)[0]
d = statistics.Discrepancy(samples, interval_multiplier)
self.assertAlmostEquals(round(d, 2), 0.25)
time_stamps_a = [0, 1, 2, 3, 5, 6]
time_stamps_b = [0, 1, 2, 3, 5, 7]
time_stamps_c = [0, 2, 3, 4]
time_stamps_d = [0, 2, 3, 4, 5]
d_abs_a = statistics.FrameDiscrepancy(time_stamps_a, True,
interval_multiplier)
d_abs_b = statistics.FrameDiscrepancy(time_stamps_b, True,
interval_multiplier)
d_abs_c = statistics.FrameDiscrepancy(time_stamps_c, True,
interval_multiplier)
d_abs_d = statistics.FrameDiscrepancy(time_stamps_d, True,
interval_multiplier)
d_rel_a = statistics.FrameDiscrepancy(time_stamps_a, False,
interval_multiplier)
d_rel_b = statistics.FrameDiscrepancy(time_stamps_b, False,
interval_multiplier)
d_rel_c = statistics.FrameDiscrepancy(time_stamps_c, False,
interval_multiplier)
d_rel_d = statistics.FrameDiscrepancy(time_stamps_d, False,
interval_multiplier)
self.assertTrue(d_abs_a < d_abs_b)
self.assertTrue(d_rel_a < d_rel_b)
self.assertTrue(d_rel_d < d_rel_c)
self.assertEquals(round(d_abs_d, 2), round(d_abs_c, 2))
def AddResults(self, tab, results):
# List of raw frame times.
results.Add('frame_times', 'ms', self._stats.frame_times)
# Arithmetic mean of frame times.
mean_frame_time = statistics.ArithmeticMean(self._stats.frame_times,
len(self._stats.frame_times))
results.Add('mean_frame_time', 'ms', round(mean_frame_time, 3))
# Absolute discrepancy of frame time stamps.
jank = statistics.FrameDiscrepancy(self._stats.frame_timestamps)
results.Add('jank', '', round(jank, 4))
# Are we hitting 60 fps for 95 percent of all frames? (Boolean value)
# We use 17ms as a slightly looser threshold, instead of 1000.0/60.0.
results.Add('mostly_smooth', '',
statistics.Percentile(self._stats.frame_times, 95.0) < 17.0)
def AddResults(self, tab, results):
if self._stats.mouse_wheel_scroll_latency:
mean_mouse_wheel_scroll_latency = statistics.ArithmeticMean(
self._stats.mouse_wheel_scroll_latency,
len(self._stats.mouse_wheel_scroll_latency))
results.Add('mean_mouse_wheel_scroll_latency', 'ms',
round(mean_mouse_wheel_scroll_latency, 3))
if self._stats.touch_scroll_latency:
mean_touch_scroll_latency = statistics.ArithmeticMean(
self._stats.touch_scroll_latency,
len(self._stats.touch_scroll_latency))
results.Add('mean_touch_scroll_latency', 'ms',
round(mean_touch_scroll_latency, 3))
if self._stats.js_touch_scroll_latency:
mean_js_touch_scroll_latency = statistics.ArithmeticMean(
self._stats.js_touch_scroll_latency,
len(self._stats.js_touch_scroll_latency))
results.Add('mean_js_touch_scroll_latency', 'ms',
round(mean_js_touch_scroll_latency, 3))
# List of raw frame times.
frame_times = FlattenList(self._stats.frame_times)
results.Add('frame_times', 'ms', frame_times)
# Arithmetic mean of frame times.
mean_frame_time = statistics.ArithmeticMean(frame_times,
len(frame_times))
results.Add('mean_frame_time', 'ms', round(mean_frame_time, 3))
# Absolute discrepancy of frame time stamps.
jank = statistics.FrameDiscrepancy(self._stats.frame_timestamps)
results.Add('jank', '', round(jank, 4))
# Are we hitting 60 fps for 95 percent of all frames?
# We use 19ms as a somewhat looser threshold, instead of 1000.0/60.0.
percentile_95 = statistics.Percentile(frame_times, 95.0)
results.Add('mostly_smooth', 'score',
1.0 if percentile_95 < 19.0 else 0.0)
if tab.browser.platform.IsRawDisplayFrameRateSupported():
for r in tab.browser.platform.GetRawDisplayFrameRateMeasurements():
if r.value is None:
raise MissingDisplayFrameRateError(r.name)
results.Add(r.name, r.unit, r.value)
def testCalcResultsTraceEvents(self):
# Make the test repeatable by seeding the random number generator
# (which is used by the mock timer) with a constant number.
random.seed(1234567)
mock_timer = MockTimer()
trace_events = []
total_time_seconds = 0.0
num_frames_sent = 0.0
first_frame = True
previous_frame_time = None
# This list represents time differences between frames in milliseconds.
expected_frame_times = []
# Append start trace events for the timeline marker and gesture marker,
# with some amount of time in between them.
trace_events.append({
'name': RENDERER_PROCESS_MARKER,
'tts': mock_timer.microseconds,
'args': {},
'pid': 20978,
'ts': mock_timer.microseconds,
'cat': 'webkit',
'tid': 11,
'ph': 'S', # Phase: start.
'id': '0x12345'
})
mock_timer.Advance()
trace_events.append({
'name': SYNTHETIC_GESTURE_MARKER,
'tts': mock_timer.microseconds,
'args': {},
'pid': 20978,
'ts': mock_timer.microseconds,
'cat': 'webkit',
'tid': 11,
'ph': 'S',
'id': '0xabcde'
})
# Generate 100 random mock frames and append their trace events.
for _ in xrange(0, 100):
mock_frame = MockFrame(mock_timer)
mock_frame.AppendTraceEventForMainThreadStats(trace_events)
mock_frame.AppendTraceEventForImplThreadStats(trace_events)
# Exclude the first frame, because it may have started before the
# benchmark run.
if not first_frame:
total_time_seconds += mock_frame.duration / 1e6
num_frames_sent += mock_frame.main_stats['frame_count']
num_frames_sent += mock_frame.impl_stats['frame_count']
first_frame = False
current_frame_time = mock_timer.microseconds / 1000.0
if previous_frame_time:
difference = current_frame_time - previous_frame_time
difference = round(difference, 2)
expected_frame_times.append(difference)
previous_frame_time = current_frame_time
# Append finish trace events for the timeline and gesture markers, in the
# reverse order from how they were added, with some time in between.
trace_events.append({
'name': SYNTHETIC_GESTURE_MARKER,
'tts': mock_timer.microseconds,
'args': {},
'pid': 20978,
'ts': mock_timer.microseconds,
'cat': 'webkit',
'tid': 11,
'ph': 'F', # Phase: finish.
'id': '0xabcde'
})
mock_timer.Advance()
trace_events.append({
'name': RENDERER_PROCESS_MARKER,
'tts': mock_timer.microseconds,
'args': {},
'pid': 20978,
'ts': mock_timer.microseconds,
'cat': 'webkit',
'tid': 11,
'ph': 'F',
'id': '0x12345'
})
# Create a timeline object from the trace.
trace_result = TraceResult(ChromeRawTraceResult(trace_events))
timeline = trace_result.AsTimelineModel()
# Find the timeline marker and gesture marker in the timeline,
# and create a RenderingStats object.
renderer_process_markers = timeline.FindTimelineMarkers(
RENDERER_PROCESS_MARKER)
self.assertEquals(len(renderer_process_markers), 1)
renderer_process = renderer_process_markers[0].start_thread.parent
timeline_markers = timeline.FindTimelineMarkers(
SYNTHETIC_GESTURE_MARKER)
stats = rendering_stats.RenderingStats(renderer_process,
timeline_markers)
# Make a results object and add results to it from the smoothness metric.
results = PageMeasurementResults()
results.WillMeasurePage(page.Page('http://foo.com/', None))
smoothness_metric = smoothness.SmoothnessMetric(None)
smoothness_metric.SetStats(stats)
smoothness_metric.AddResults(None, results)
results.DidMeasurePage()
self.assertEquals(expected_frame_times,
results.page_results[0]['frame_times'].value)
self.assertAlmostEquals(
1000.0 * (total_time_seconds / num_frames_sent),
results.page_results[0]['mean_frame_time'].value,
places=2)
# We don't verify the correctness of the discrepancy computation itself,
# because we have a separate unit test for that purpose.
self.assertAlmostEquals(statistics.FrameDiscrepancy(
stats.frame_timestamps, True),
results.page_results[0]['jank'].value,
places=4)
# We do not verify the correctness of Percentile here; Percentile should
# have its own test.
# The 17 here represents a threshold of 17 ms; this should match the value
# in the smoothness metric.
self.assertEquals(
statistics.Percentile(expected_frame_times, 95.0) < 17.0,
results.page_results[0]['mostly_smooth'].value)