[Telemetry] Output average GPU frequency from power metric

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 67 matching lines @@
 
     self._StopInternal()
 
   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)
 
+    gpu_freq_hz = (
+        self._results['component_utilization']['gpu']['average_frequency_mhz'])
+    results.Add('gpu_average_frequency_hz', 'hz', gpu_freq_hz)

[tonyg, 2014/04/01 16:19:43]

Seems like we're missing the multiplication from mhz to hz.

Perhaps the unittest should check for this stat in the test that is based on a
static powermetrics output file.

Finally, should we check for the existence of 'gpu' and 'average_frequency_mhz'
before trying to access it and just silently not output this stat if
unavailable?

+
     # Add idle wakeup numbers for all processes.
     for process_type in self._results['cpu_stats']:
       trace_name_for_process = 'idle_wakeups_%s' % (process_type.lower())
       results.Add(trace_name_for_process, 'count',
                   self._results['cpu_stats'][process_type])
 
     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
     idle_wakeup_delta = (cpu_stats[process_type]['IdleWakeupCount'] -
                         start_cpu_stats[process_type]['IdleWakeupCount'])
     cpu_delta[process_type] = idle_wakeup_delta
   return cpu_delta