Collecting LatencyInfo in telemetry

tools/perf/metrics/smoothness.py

Index: tools/perf/metrics/smoothness.py
diff --git a/tools/perf/metrics/smoothness.py b/tools/perf/metrics/smoothness.py
index 6d304097223287dcf789eaa53e36b663db0aa79f..9c1b47365dc20d3c7d222dfbb93764567c51cf22 100644
--- a/tools/perf/metrics/smoothness.py
+++ b/tools/perf/metrics/smoothness.py
@@ -64,8 +64,10 @@ class SmoothnessMetric(Metric):
                         for action in self._actions ]
 
     renderer_process = timeline_model.GetRendererProcessFromTab(tab)
+    browser_main_thread = timeline_model.GetBrowserMainThread()
+
     self._stats = rendering_stats.RenderingStats(
-        renderer_process, timeline_ranges)
+        renderer_process, browser_main_thread, timeline_ranges)
 
     if not self._stats.frame_times:
       raise NotEnoughFramesError()
@@ -77,6 +79,33 @@ class SmoothnessMetric(Metric):
     self._stats = stats
 
   def AddResults(self, tab, results):
+    if self._stats.mouse_wheel_latency:
+      mean_mouse_wheel_latency = statistics.ArithmeticMean(
+          self._stats.mouse_wheel_latency, len(self._stats.mouse_wheel_latency))
+      results.Add('mean_mouse_wheel_latency', 'ms',

[nduca, 2014/01/23 18:34:45]

why report mean and 95%ile?

can you do an experiment where you print out all the latency values from top_25
on a chromebook and then put those into a spreadsheet so we can see what the
histogram of the data are?

[Yufeng Shen (Slow to review), 2014/01/30 01:16:05]

So I only keep the mean value in the new patch.

I have sent out an email "Some scrolling latency data on Pixel & Nexus 7" to the
chrome-input about some of the patterns of the test results. Until we are
confident which metrics we want to track, lets just use the mean value for now.

+                  round(mean_mouse_wheel_latency, 3))
+      results.Add('mouse_wheel_latency_95%', 'ms',
+                  statistics.Percentile(self._stats.mouse_wheel_latency, 95.0))
+
+    if self._stats.gesture_scroll_latency:
+      mean_gesture_scroll_latency = statistics.ArithmeticMean(
+          self._stats.gesture_scroll_latency,
+          len(self._stats.gesture_scroll_latency))
+      results.Add('mean_gesture_scroll_latency', 'ms',
+                  round(mean_gesture_scroll_latency, 3))
+      results.Add('gesture_scroll_latency_95%', 'ms',
+                  statistics.Percentile(self._stats.gesture_scroll_latency,
+                                        95.0))
+
+    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))
+      results.Add('touch_scroll_latency_95%', 'ms',
+                  statistics.Percentile(self._stats.touch_scroll_latency,
+                                        95.0))
     # List of raw frame times.
     results.Add('frame_times', 'ms', self._stats.frame_times)