Collecting LatencyInfo in telemetry

tools/perf/metrics/rendering_stats.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from operator import attrgetter
 
 
 class RenderingStats(object):
-  def __init__(self, renderer_process, timeline_ranges):
+  def __init__(self, renderer_process, browser_process, timeline_ranges):
     """
     Utility class for extracting rendering statistics from the timeline (or
     other loggin facilities), and providing them in a common format to classes
     that compute benchmark metrics from this data.
 
     Stats can either be numbers, or lists of numbers. Classes that calculate
     metrics from the stats must be able to handle both cases. The length of
     different list stats may vary.
 
     All *_time values are measured in milliseconds.
     """
     assert(len(timeline_ranges) > 0)
     self.renderer_process = renderer_process
+    self.browser_process = browser_process
 
     self.frame_timestamps = []
     self.frame_times = []
     self.paint_time = []
     self.painted_pixel_count = []
     self.record_time = []
     self.recorded_pixel_count = []
     self.rasterize_time = []
     self.rasterized_pixel_count = []
+    self.mouse_wheel_latency = []
+    self.gesture_scroll_latency = []
+    self.touch_scroll_latency = []
 
     for timeline_range in timeline_ranges:
       if timeline_range.is_empty:
         continue
       self.initMainThreadStatsFromTimeline(timeline_range)
       self.initImplThreadStatsFromTimeline(timeline_range)
+      self.initInputLatencyFromTimeline(timeline_range)
+
+  def initInputLatencyFromTimeline(self, timeline_range):

[nduca, 2014/01/13 18:49:32]

needs unit tests too

[Yufeng Shen (Slow to review), 2014/01/14 00:05:47]

unittests added in 
tools/perf/metrics/rendering_stats_unittest.py

+    event_name = "InputLatency"
+    ui_comp_name = 'INPUT_EVENT_LATENCY_UI_COMPONENT'
+    begin_comp_name = 'INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT'
+    end_comp_name = 'INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT'
+    mouse_wheel_events = []
+    scroll_events = []
+    for event in self.browser_process.IterAllAsyncSlicesOfName(event_name):
+      if event.start >= timeline_range.min and event.end <= timeline_range.max:
+        for ss in event.sub_slices:
+          if 'step' not in ss.args:
+            continue
+          if 'data' not in ss.args:
+            continue
+          if ss.args['step'] == 'MouseWheel':
+            mouse_wheel_events.append(ss)
+          elif ss.args['step'] == 'GestureScrollUpdate':
+            scroll_events.append(ss)
+
+    # mouse_wheel_latency is the time from when mouse wheel event reaches RWH
+    # to buffer swapped.
+    for event in mouse_wheel_events:
+      data = event.args['data']
+      if begin_comp_name in data and end_comp_name in data:
+        latency = data[end_comp_name]['time'] - data[begin_comp_name]['time']
+        self.mouse_wheel_latency.append(latency / 1000.0)
+
+    # gesture_scroll_latency is the time from when gesture scroll event reaches
+    # RWH to buffer swapped. It is available on all platforms.
+    # touch_scroll_latency is the time from when the touch event reaches browser
+    # to when the buffer swapped due to the scroll generated from the original
+    # touch event. This is only available in Aura currently.
+    for event in scroll_events:
+      data = event.args['data']
+      if begin_comp_name in data and end_comp_name in data:
+        latency = data[end_comp_name]['time'] - data[begin_comp_name]['time']
+        self.gesture_scroll_latency.append(latency / 1000.0)
+      if ui_comp_name in data and end_comp_name in data:
+        latency = data[end_comp_name]['time'] - data[ui_comp_name]['time']
+        self.touch_scroll_latency.append(latency / 1000.0)
 
   def initMainThreadStatsFromTimeline(self, timeline_range):
     event_name = 'BenchmarkInstrumentation::MainThreadRenderingStats'
     events = []
     for event in self.renderer_process.IterAllSlicesOfName(event_name):
       if event.start >= timeline_range.min and event.end <= timeline_range.max:
         if 'data' not in event.args:
           continue
         events.append(event)
     events.sort(key=attrgetter('start'))
@@ skipping 38 matching lines @@
         self.frame_timestamps.append(
             event.start)
         if not first_frame:
           self.frame_times.append(round(self.frame_timestamps[-1] -
                                         self.frame_timestamps[-2], 2))
         first_frame = False
       self.rasterize_time.append(1000.0 *
           event.args['data']['rasterize_time'])
       self.rasterized_pixel_count.append(
           event.args['data']['rasterized_pixel_count'])