Using decorator for power monitoring.

tools/perf/metrics/power.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 logging
 
 from metrics import Metric
 from telemetry.core.platform import factory
 
 
@@ skipping 61 matching lines @@
 
   def Stop(self, _, tab):
     if not PowerMetric.enabled:
       return
 
     if not tab.browser.platform.CanMonitorPower():
       return
 
     self._StopInternal()
 
-  def AddResults(self, _, results):
+  def AddResults(self, _, results, prefix=''):
     if not self._results:
       return
 
     energy_consumption_mwh = self._results.get('energy_consumption_mwh')
     # Testing for None, as 0 is a valid value.
     if energy_consumption_mwh is not None:
-      results.Add('energy_consumption_mwh', 'mWh', energy_consumption_mwh)
+      results.Add('%senergy_consumption_mwh' % prefix, 'mWh',
+                  energy_consumption_mwh)
 
     component_utilization = self._results.get('component_utilization', {})
     # GPU Frequency.
     gpu_power = component_utilization.get('gpu', {})
     gpu_freq_hz = gpu_power.get('average_frequency_hz')
     # Testing for None, as 0 is a valid value.
     if gpu_freq_hz is not None:
-      results.Add('gpu_average_frequency_hz', 'hz', gpu_freq_hz)
+      results.Add('%sgpu_average_frequency_hz' % prefix, 'hz', gpu_freq_hz)
 
     # Add idle wakeup numbers for all processes.
     for (process_type, stats) in self._results.get('cpu_stats', {}).items():
-      trace_name_for_process = 'idle_wakeups_%s' % (process_type.lower())
+      trace_name_for_process = '%sidle_wakeups_%s' % (prefix,
+                                                      process_type.lower())
       results.Add(trace_name_for_process, 'count', stats)
 
     self._results = None
 
 def _SubtractCpuStats(cpu_stats, start_cpu_stats):
   """Computes number of idle wakeups that occurred over measurement period.
 
   Each of the two cpu_stats arguments is a dict as returned by the
   Browser.cpu_stats call.
 
   Returns:
     A dict of process type names (Browser, Renderer, etc.) to idle wakeup count
     over the period recorded by the input.
   """
   cpu_delta = {}
   for process_type in cpu_stats:
     assert process_type in start_cpu_stats, 'Mismatching process types'
     # Skip any process_types that are empty.
     if (not cpu_stats[process_type]) or (not start_cpu_stats[process_type]):
       continue
     # Skip if IdleWakeupCount is not present.
     if (('IdleWakeupCount' not in cpu_stats[process_type]) or
         ('IdleWakeupCount' not in start_cpu_stats[process_type])):
       continue
     idle_wakeup_delta = (cpu_stats[process_type]['IdleWakeupCount'] -
                         start_cpu_stats[process_type]['IdleWakeupCount'])
     cpu_delta[process_type] = idle_wakeup_delta
   return cpu_delta