Android: splits cache_control and perf_control.

build/android/pylib/perf/perf_control.py

+# Copyright 2013 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
+
+
+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')
+  _KERNEL_MAX = '/sys/devices/system/cpu/kernel_max'
+
+  def __init__(self, adb):
+    self._adb = adb
+    kernel_max = self._adb.GetFileContents(PerfControl._KERNEL_MAX,
+                                           log_result=False)
+    assert kernel_max, 'Unable to find %s' % PerfControl._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)