Adding dumpsys based power monitor for android.

tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py

Index: tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
diff --git a/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py b/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
new file mode 100644
index 0000000000000000000000000000000000000000..fae8a47ff1605ba584fcc2252d63cd23dcbbd4be
--- /dev/null
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
@@ -0,0 +1,93 @@
+# 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 telemetry.core.platform.power_monitor as power_monitor
+
+import csv
+
+from collections import defaultdict
+
+
+class DumpsysPowerMonitor(power_monitor.PowerMonitor):
+  """PowerMonitor that relies on the dumpsys batterystats to monitor the power
+  consumption of a single android application. This measure uses a heuristic
+  and is the same information end-users see with the battery application.
+  """
+  def __init__(self, adb):
+    """Constructor.
+
+    Args:
+        adb: adb proxy.
+    """
+    super(DumpsysPowerMonitor, self).__init__()
+    self._adb = adb
+    self._browser = None
+
+  def CanMonitorPower(self):
+    return self._adb.CanControlUsbCharging()
+
+  def StartMonitoringPower(self, browser):
+    assert not self._browser, (
+        'Must call StopMonitoringPower().')
+    self._browser = browser
+    # Disable the charging of the device over USB. This is necessary because the
+    # device only collects information about power usage when the device is not
+    # charging.
+    self._adb.DisableUsbCharging()
+
+  def StopMonitoringPower(self):
+    assert self._browser, (
+        'StartMonitoringPower() not called.')
+    try:
+      self._adb.EnableUsbCharging()
+      # pylint: disable=W0212
+      package = self._browser._browser_backend.package
+      # By default, 'dumpsys batterystats' measures power consumption during the
+      # last unplugged period.
+      result = self._adb.RunShellCommand('dumpsys batterystats -c %s' % package)
+      assert result, 'Dumpsys produced no output'
+      return DumpsysPowerMonitor.ParseSamplingOutput(package, result)
+    finally:
+      self._browser = None
+
+  @staticmethod
+  def ParseSamplingOutput(package, dumpsys_output):
+    """Parse output of 'dumpsys batterystats -c'
+
+    Returns:
+        Dictionary in the format returned by StopMonitoringPower().
+    """
+    # csv columns
+    DUMP_VERSION_INDEX = 0
+    COLUMN_TYPE_INDEX = 3
+    PACKAGE_UID_INDEX = 4
+    PWI_POWER_COMSUMPTION_INDEX = 5
+    PWI_UID_INDEX = 1
+    PWI_AGGREGATION_INDEX = 2
+    PWI_SUBTYPE_INDEX = 4
+    csvreader = csv.reader(dumpsys_output)
+    entries_by_type = defaultdict(list)
+    for entry in csvreader:
+      if len(entry) < 4 or entry[DUMP_VERSION_INDEX] != '7':
+        continue
+      entries_by_type[entry[COLUMN_TYPE_INDEX]].append(entry)
+    # Find the uid of for the given package.
+    assert package in entries_by_type, 'Expected package not found'
+    assert len(entries_by_type[package]) == 1, 'Multiple entries for package.'
+    uid = entries_by_type[package][0][PACKAGE_UID_INDEX]
+    consumptions_mah = [float(entry[PWI_POWER_COMSUMPTION_INDEX])
+                        for entry in entries_by_type['pwi']
+                        if entry[PWI_UID_INDEX] == uid and
+                        entry[PWI_AGGREGATION_INDEX] == 't' and
+                        entry[PWI_SUBTYPE_INDEX] == 'uid']
+    consumption_mah = sum(consumptions_mah)
+    # Converting at a nominal voltage of 4.0V, as those values are obtained by a
+    # heuristic, and 4.0V is the voltage we set when using a monsoon device.
+    consumption_mwh = consumption_mah * 4.0
+    # Raw power usage samples.
+    out_dict = {}
+    out_dict['identifier'] = 'dumpsys'
+    out_dict['power_samples_mw'] = []
+    out_dict['energy_consumption_mwh'] = consumption_mwh
+    return out_dict