[Telemetry] Add power usage metric

* Add a power usage metric and add sample usage in startup test.
* OS X: Only print power metrics stderr output when passing -v to Telemetry due to console spew.

BUG=336565,336672,336555

Review URL: https://codereview.chromium.org/144543007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247100 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 75 insertions, 8 deletions

diff --git a/tools/perf/measurements/smoothness.py b/tools/perf/measurements/smoothness.py
index 4715afa..a84a4ac 100644
--- a/tools/perf/measurements/smoothness.py
+++ b/tools/perf/measurements/smoothness.py
@@ -2,29 +2,37 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from metrics import power
 from metrics import smoothness
 from telemetry.page import page_measurement
 
+
 class Smoothness(page_measurement.PageMeasurement):
   def __init__(self):
     super(Smoothness, self).__init__('smoothness')
-    self._metric = None
+    self._smoothness_metric = None
+    self._power_metric = None
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs('--enable-gpu-benchmarking')
+    power.PowerMetric.CustomizeBrowserOptions(options)
 
   def CanRunForPage(self, page):
     return hasattr(page, 'smoothness')
 
   def WillRunActions(self, page, tab):
-    self._metric = smoothness.SmoothnessMetric()
-    self._metric.Start(page, tab)
+    self._power_metric = power.PowerMetric()
+    self._power_metric.Start(page, tab)
+    self._smoothness_metric = smoothness.SmoothnessMetric()
+    self._smoothness_metric.Start(page, tab)
 
   def DidRunAction(self, page, tab, action):
-    self._metric.AddActionToIncludeInMetric(action)
+    self._smoothness_metric.AddActionToIncludeInMetric(action)
 
   def DidRunActions(self, page, tab):
-    self._metric.Stop(page, tab)
+    self._power_metric.Stop(page, tab)
+    self._smoothness_metric.Stop(page, tab)
 
   def MeasurePage(self, page, tab, results):
-    self._metric.AddResults(tab, results)
+    self._power_metric.AddResults(tab, results)
+    self._smoothness_metric.AddResults(tab, results)
diff --git a/tools/perf/metrics/power.py b/tools/perf/metrics/power.py
new file mode 100644
index 0000000..32461ce
--- /dev/null
+++ b/tools/perf/metrics/power.py
@@ -0,0 +1,48 @@
+# 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 logging
+
+from metrics import Metric
+
+
+class PowerMetric(Metric):
+  """A metric for measuring power usage."""
+
+  _enabed = True
+
+  def __init__(self):
+    super(PowerMetric, self).__init__()
+    self._results = None
+
+  @classmethod
+  def CustomizeBrowserOptions(cls, options):
+    PowerMetric._enabed = options.report_root_metrics
+
+  def Start(self, _, tab):
+    if not PowerMetric._enabed:
+      return
+
+    if not tab.browser.platform.CanMonitorPowerAsync():
+      logging.warning("System doesn't support async power monitoring.")
+      return
+
+    tab.browser.platform.StartMonitoringPowerAsync()
+
+  def Stop(self, _, tab):
+    if not PowerMetric._enabed:
+      return
+
+    if not tab.browser.platform.CanMonitorPowerAsync():
+      return
+
+    self._results = tab.browser.platform.StopMonitoringPowerAsync()
+
+  def AddResults(self, _, results):
+    if not self._results:
+      return
+
+    energy_consumption_mwh = self._results['energy_consumption_mwh']
+    results.Add('energy_consumption_mwh', 'mWh', energy_consumption_mwh)
+    self._results = None
diff --git a/tools/perf/unit-info.json b/tools/perf/unit-info.json
index 0986211a..b5f5150 100644
--- a/tools/perf/unit-info.json
+++ b/tools/perf/unit-info.json
@@ -68,6 +68,10 @@
   "milliseconds-per-frame": {
     "improvement_direction": "down"
   },
+  "mWh": {
+    "improvement_direction": "down",
+    "why": "Fewer milliwatt-hours means less energy consumed."
+  },
   "objects (bigger is better)": {
     "improvement_direction": "up",
     "why": "Used in spaceport benchmark."
diff --git a/tools/telemetry/telemetry/core/platform/mac_platform_backend.py b/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
index fbf519c..5f27c35 100644
--- a/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
+++ b/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import ctypes
+import logging
 import os
 import plistlib
 import signal
@@ -35,9 +36,15 @@ class MacPlatformBackend(posix_platform_backend.PosixPlatformBackend):
       self._powermetrics_output_file = tempfile.NamedTemporaryFile().name
       args = [self.binary_path, '-f', 'plist', '-i',
           '%d' % SAMPLE_INTERVAL_MS, '-u', self._powermetrics_output_file]
-      # TODO(jeremy): Need to ensure command is run as root user.
+
+      # powermetrics writes lots of output to stderr, don't echo unless verbose
+      # logging enabled.
+      stderror_destination = subprocess.PIPE
+      if logging.getLogger().isEnabledFor(logging.DEBUG):
+        stderror_destination = None
+
       self._powermetrics_process = subprocess.Popen(args,
-          stdout=subprocess.PIPE)
+          stdout=subprocess.PIPE, stderr=stderror_destination)
 
     def StopMonitoringPowerAsync(self):
       assert self._powermetrics_process, (