Dump raw tracing data when smoothness_controlller fails to issue timeline marker.

tools/perf/measurements/smoothness_controller.py

 # Copyright 2014 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.
+import sys
 
 from measurements import smooth_gesture_util
 from metrics import smoothness
 from telemetry.core.timeline.model import TimelineModel
 from telemetry.page import page_measurement
 from telemetry.page.actions import action_runner
 from telemetry.web_perf import timeline_interaction_record as tir_module
 
 
 RUN_SMOOTH_ACTIONS = 'RunSmoothAllActions'
 
 
 class MissingDisplayFrameRateError(page_measurement.MeasurementFailure):
   def __init__(self, name):
     super(MissingDisplayFrameRateError, self).__init__(
       'Missing display frame rate metrics: ' + name)
 
 class SmoothnessController(object):
   def __init__(self):
     self._timeline_model = None
+    self._tracing_timeline_data = None
 
   def Start(self, page, tab):
     custom_categories = ['webkit.console', 'benchmark']
     custom_categories += page.GetSyntheticDelayCategories()
     tab.browser.StartTracing(','.join(custom_categories), 60)
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       tab.browser.platform.StartRawDisplayFrameRateMeasurement()
     # Start the smooth marker for all smooth actions.
     runner = action_runner.ActionRunner(None, tab)
     runner.BeginInteraction(RUN_SMOOTH_ACTIONS, [tir_module.IS_SMOOTH])
 
   def Stop(self, tab):
     # End the smooth marker for all smooth actions.
     runner = action_runner.ActionRunner(None, tab)
     runner.EndInteraction(RUN_SMOOTH_ACTIONS, [tir_module.IS_SMOOTH])
     # Stop tracing for smoothness metric.
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       tab.browser.platform.StopRawDisplayFrameRateMeasurement()
-    tracing_timeline_data = tab.browser.StopTracing()
-    self._timeline_model = TimelineModel(timeline_data=tracing_timeline_data)
+    self._tracing_timeline_data = tab.browser.StopTracing()
+    self._timeline_model = TimelineModel(
+      timeline_data=self._tracing_timeline_data)
 
   def AddResults(self, tab, results):
     # Add results of smoothness metric. This computes the smoothness metric for
     # the time ranges of gestures, if there is at least one, else the the time
     # ranges from the first action to the last action.
 
     renderer_thread = self._timeline_model.GetRendererThreadFromTab(tab)
     run_smooth_actions_record = None
     smooth_records = []
     for event in renderer_thread.async_slices:
       if not tir_module.IsTimelineInteractionRecord(event.name):
         continue
       r = tir_module.TimelineInteractionRecord.FromEvent(event)
       if r.logical_name == RUN_SMOOTH_ACTIONS:
         assert run_smooth_actions_record is None, (
           'SmoothnessController cannot issue more than 1 %s record' %
           RUN_SMOOTH_ACTIONS)
         run_smooth_actions_record = r
       elif r.is_smooth:
         smooth_records.append(
           smooth_gesture_util.GetAdjustedInteractionIfContainGesture(
             self._timeline_model, r))
 
     # If there is no other smooth records, we make measurements on time range
     # marked smoothness_controller itself.
     # TODO(nednguyen): when crbug.com/239179 is marked fixed, makes sure that
     # page sets are responsible for issueing the markers themselves.
     if len(smooth_records) == 0:
-      assert run_smooth_actions_record, (
-        'SmoothnessController fails to issue markers for the whole '
-        'interaction.')
-      smooth_records = [run_smooth_actions_record]
+      if run_smooth_actions_record is None:
+        sys.stderr.write('Raw tracing data:\n')
+        sys.stderr.write(repr(self._tracing_timeline_data.EventData()))
+        sys.stderr.write('\n')
+        raise Exception('SmoothnessController failed to issue markers for the '
+                        'whole interaction.')
+      else:
+        smooth_records = [run_smooth_actions_record]
 
     # Create an interaction_record for this legacy measurement. Since we don't
     # wrap the results that is sent to smoothnes metric, the logical_name will
     # not be used.
     smoothness_metric = smoothness.SmoothnessMetric()
     smoothness_metric.AddResults(
       self._timeline_model, renderer_thread, smooth_records, results)
     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 CleanUp(self, tab):
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       tab.browser.platform.StopRawDisplayFrameRateMeasurement()
     if tab.browser.is_tracing_running:
       tab.browser.StopTracing()