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..ed2894867d3ba36a87964a95001922f25a366778
--- /dev/null
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
@@ -0,0 +1,78 @@
+# 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):

[jeremy, 2014/04/03 11:16:30]

Can you add a header comment, especially interesting is the guarantees and
precision of this power monitor vs other types of power monitoring.

[qsr, 2014/04/03 12:02:43]

Done.

+  def __init__(self, adb):

[jeremy, 2014/04/03 11:16:30]

Comment input parameters

[qsr, 2014/04/03 12:02:43]

Done.

+    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
+    self._adb.DisableUsbCharging()

[jeremy, 2014/04/03 11:16:30]

What does this line do exactly? Can you add a comment?

[qsr, 2014/04/03 12:02:43]

Done.

+
+  def StopMonitoringPower(self):
+    assert self._browser, (
+        'StartMonitoringPower() not called.')
+    try:
+      self._adb.EnableUsbCharging()
+      package = self._browser._browser_backend.package
+      result = self._adb.RunShellCommand('dumpsys batterystats -c %s' % package)

[jeremy, 2014/04/03 11:16:30]

I take it that dumpsys measures from disable->enable ?

[qsr, 2014/04/03 12:02:43]

Done.

+      assert result, 'DumpSys produced no output'

[jeremy, 2014/04/03 11:16:30]

nit: Dumpsys per capitalization in
http://source.android.com/devices/tech/input/dumpsys.html .

[qsr, 2014/04/03 12:02:43]

Done.

+      return DumpsysPowerMonitor.ParseSamplingOutput(package, result)
+    finally:
+      self._browser = None
+
+  @staticmethod
+  def ParseSamplingOutput(package, dumpsys_output):

[jeremy, 2014/04/03 11:16:30]

Do you also get any kind of stat which could give an indication of how hard the
GPU is working?

[qsr, 2014/04/03 12:02:43]

 Not at this moment. When/If android starts collecting this data, we should get
it for free.

+    """Parse output of 'dumpsys batterystats -c'
+
+    Returns:
+        Dictionary in the format returned by StopMonitoringPower().
+    """
+    # cvs columns

[jeremy, 2014/04/03 11:16:30]

nit: s/cvs/csv/

[qsr, 2014/04/03 12:02:43]

Done.

+    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

[jeremy, 2014/04/03 11:16:30]

nit: .

[qsr, 2014/04/03 12:02:43]

Done.

+    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_mha = [float(entry[PWI_POWER_COMSUMPTION_INDEX])

[jeremy, 2014/04/03 11:16:30]

_mah ?

[qsr, 2014/04/03 12:02:43]

Done.

+                        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_mha)
+    # 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