1 # Copyright 2013 The Chromium Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 6 import logging 7 8 9 class PerfControl(object): 10 """Provides methods for setting the performance mode of a device.""" 11 _SCALING_GOVERNOR_FMT = ( 12 '/sys/devices/system/cpu/cpu%d/cpufreq/scaling_governor') 13 _KERNEL_MAX = '/sys/devices/system/cpu/kernel_max' 14 15 def __init__(self, adb): 16 self._adb = adb 17 kernel_max = self._adb.GetFileContents(PerfControl._KERNEL_MAX, 18 log_result=False) 19 assert kernel_max, 'Unable to find %s' % PerfControl._KERNEL_MAX 20 self._kernel_max = int(kernel_max[0]) 21 logging.info('Maximum CPU index: %d', self._kernel_max) 22 self._original_scaling_governor = self._adb.GetFileContents( 23 PerfControl._SCALING_GOVERNOR_FMT % 0, 24 log_result=False)[0] 25 26 def SetHighPerfMode(self): 27 """Sets the highest possible performance mode for the device.""" 28 self._SetScalingGovernorInternal('performance') 29 30 def SetDefaultPerfMode(self): 31 """Sets the performance mode for the device to its default mode.""" 32 product_model = self._adb.GetProductModel() 33 governor_mode = { 34 'GT-I9300': 'pegasusq', 35 'Galaxy Nexus': 'interactive', 36 'Nexus 4': 'ondemand', 37 'Nexus 7': 'interactive', 38 'Nexus 10': 'interactive' 39 }.get(product_model, 'ondemand') 40 self._SetScalingGovernorInternal(governor_mode) 41 42 def RestoreOriginalPerfMode(self): 43 """Resets the original performance mode of the device.""" 44 self._SetScalingGovernorInternal(self._original_scaling_governor) 45 46 def _SetScalingGovernorInternal(self, value): 47 for cpu in range(self._kernel_max + 1): 48 scaling_governor_file = PerfControl._SCALING_GOVERNOR_FMT % cpu 49 if self._adb.FileExistsOnDevice(scaling_governor_file): 50 logging.info('Writing scaling governor mode \'%s\' -> %s', 51 value, scaling_governor_file) 52 self._adb.SetProtectedFileContents(scaling_governor_file, value) 53
