AndroidParf: log max CPU index when running tests

build/android/pylib/perf_tests_helper.py

 # Copyright (c) 2012 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 re
 import sys
 
 import android_commands
 import json
+import logging
 import math
 
 # Valid values of result type.
 RESULT_TYPES = {'unimportant': 'RESULT ',
                 'default': '*RESULT ',
                 'informational': '',
                 'unimportant-histogram': 'HISTOGRAM ',
                 'histogram': '*HISTOGRAM '}
 
 
@@ skipping 125 matching lines @@
 
 
 class PerfControl(object):
   """Provides methods for setting the performance mode of a device."""
   _SCALING_GOVERNOR_FMT = (
       '/sys/devices/system/cpu/cpu%d/cpufreq/scaling_governor')
 
   def __init__(self, adb):
     self._adb = adb
     kernel_max = self._adb.GetFileContents('/sys/devices/system/cpu/kernel_max',
-                                         log_result=False)
+                                           log_result=False)
     assert kernel_max, 'Unable to find /sys/devices/system/cpu/kernel_max'
     self._kernel_max = int(kernel_max[0])
+    logging.info('Maximum CPU index: %d' % self._kernel_max)
     self._original_scaling_governor = self._adb.GetFileContents(
       PerfControl._SCALING_GOVERNOR_FMT % 0,
       log_result=False)[0]
 
   def SetHighPerfMode(self):
     """Sets the highest possible performance mode for the device."""
     self._SetScalingGovernorInternal('performance')
 
   def SetDefaultPerfMode(self):
     """Sets the performance mode for the device to its default mode."""
     product_model = self._adb.GetProductModel()
     governor_mode = {
                     "GT-I9300" : 'pegasusq',
                     "Galaxy Nexus" : 'interactive',
                     "Nexus 4" : 'ondemand',
                     "Nexus 7" : 'interactive',
                     "Nexus 10": 'interactive'
                     }.get(product_model, 'ondemand')
     self._SetScalingGovernorInternal(governor_mode)
 
   def RestoreOriginalPerfMode(self):
     """Resets the original performance mode of the device."""
     self._SetScalingGovernorInternal(self._original_scaling_governor)
 
   def _SetScalingGovernorInternal(self, value):
     for cpu in range(self._kernel_max + 1):
       scaling_governor_file = PerfControl._SCALING_GOVERNOR_FMT % cpu
       if self._adb.FileExistsOnDevice(scaling_governor_file):
+        logging.info('Writing scaling governor mode \'%s\' -> %s' %
+                     (value, scaling_governor_file))
         self._adb.SetProtectedFileContents(scaling_governor_file, value)