build/android/pylib/perf/perf_control.py

   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 import atexit
   6 import logging
   7
   8 from pylib import android_commands
   9 from pylib.device import device_utils
  10
  11 class PerfControl(object):
  12   """Provides methods for setting the performance mode of a device."""
  13   _CPU_PATH = '/sys/devices/system/cpu'
  14   _KERNEL_MAX = '/sys/devices/system/cpu/kernel_max'
  15
  16   def __init__(self, device):
  17     # TODO(jbudorick) Remove once telemetry gets switched over.
  18     if isinstance(device, android_commands.AndroidCommands):
  19       device = device_utils.DeviceUtils(device)
  20     self._device = device
  21     # this will raise an AdbCommandFailedError if no CPU files are found
  22     self._cpu_files = self._device.RunShellCommand(
  23         'ls -d cpu[0-9]*', cwd=self._CPU_PATH, check_return=True, as_root=True)
  24     assert self._cpu_files, 'Failed to detect CPUs.'
  25     self._cpu_file_list = ' '.join(self._cpu_files)
  26     logging.info('CPUs found: %s', self._cpu_file_list)
  27     self._have_mpdecision = self._device.FileExists('/system/bin/mpdecision')
  28
  29   def SetHighPerfMode(self):
  30     """Sets the highest stable performance mode for the device."""
  31     if not self._device.old_interface.IsRootEnabled():
  32       message = 'Need root for performance mode. Results may be NOISY!!'
  33       logging.warning(message)
  34       # Add an additional warning at exit, such that it's clear that any results
  35       # may be different/noisy (due to the lack of intended performance mode).
  36       atexit.register(logging.warning, message)
  37       return
  38
  39     product_model = self._device.product_model
  40     # TODO(epenner): Enable on all devices (http://crbug.com/383566)
  41     if 'Nexus 4' == product_model:
  42       self._ForceAllCpusOnline(True)
  43       if not self._AllCpusAreOnline():
  44         logging.warning('Failed to force CPUs online. Results may be NOISY!')
  45       self._SetScalingGovernorInternal('performance')
  46     elif 'Nexus 5' == product_model:
  47       self._ForceAllCpusOnline(True)
  48       if not self._AllCpusAreOnline():
  49         logging.warning('Failed to force CPUs online. Results may be NOISY!')
  50       self._SetScalingGovernorInternal('performance')
  51       self._SetScalingMaxFreq(1190400)
  52       self._SetMaxGpuClock(200000000)
  53     else:
  54       self._SetScalingGovernorInternal('performance')
  55
  56   def SetPerfProfilingMode(self):
  57     """Enables all cores for reliable perf profiling."""
  58     self._ForceAllCpusOnline(True)
  59     self._SetScalingGovernorInternal('performance')
  60     if not self._AllCpusAreOnline():
  61       if not self._device.old_interface.IsRootEnabled():
  62         raise RuntimeError('Need root to force CPUs online.')
  63       raise RuntimeError('Failed to force CPUs online.')
  64
  65   def SetDefaultPerfMode(self):
  66     """Sets the performance mode for the device to its default mode."""
  67     if not self._device.old_interface.IsRootEnabled():
  68       return
  69     product_model = self._device.product_model
  70     if 'Nexus 5' == product_model:
  71       if self._AllCpusAreOnline():
  72         self._SetScalingMaxFreq(2265600)
  73         self._SetMaxGpuClock(450000000)
  74
  75     governor_mode = {
  76         'GT-I9300': 'pegasusq',
  77         'Galaxy Nexus': 'interactive',
  78         'Nexus 4': 'ondemand',
  79         'Nexus 5': 'ondemand',
  80         'Nexus 7': 'interactive',
  81         'Nexus 10': 'interactive'
  82     }.get(product_model, 'ondemand')
  83     self._SetScalingGovernorInternal(governor_mode)
  84     self._ForceAllCpusOnline(False)
  85
  86   def GetCpuInfo(self):
  87     online = (output.rstrip() == '1' and status == 0
  88               for (_, output, status) in self._ForEachCpu('cat "$CPU/online"'))
  89     governor = (output.rstrip() if status == 0 else None
  90                 for (_, output, status)
  91                 in self._ForEachCpu('cat "$CPU/cpufreq/scaling_governor"'))
  92     return zip(self._cpu_files, online, governor)
  93
  94   def _ForEachCpu(self, cmd):
  95     script = '; '.join([
  96         'for CPU in %s' % self._cpu_file_list,
  97         'do %s' % cmd,
  98         'echo -n "%~%$?%~%"',
  99         'done'
 100     ])
 101     output = self._device.RunShellCommand(
 102         script, cwd=self._CPU_PATH, check_return=True, as_root=True)
 103     output = '\n'.join(output).split('%~%')
 104     return zip(self._cpu_files, output[0::2], (int(c) for c in output[1::2]))
 105
 106   def _WriteEachCpuFile(self, path, value):
 107     results = self._ForEachCpu(
 108         'test -e "$CPU/{path}" && echo {value} > "$CPU/{path}"'.format(
 109             path=path, value=value))
 110     cpus = ' '.join(cpu for (cpu, _, status) in results if status == 0)
 111     if cpus:
 112       logging.info('Successfully set %s to %r on: %s', path, value, cpus)
 113     else:
 114       logging.warning('Failed to set %s to %r on any cpus')
 115
 116   def _SetScalingGovernorInternal(self, value):
 117     self._WriteEachCpuFile('cpufreq/scaling_governor', value)
 118
 119   def _SetScalingMaxFreq(self, value):
 120     self._WriteEachCpuFile('cpufreq/scaling_max_freq', '%d' % value)
 121
 122   def _SetMaxGpuClock(self, value):
 123     self._device.WriteFile('/sys/class/kgsl/kgsl-3d0/max_gpuclk',
 124                            str(value),
 125                            as_root=True)
 126
 127   def _AllCpusAreOnline(self):
 128     results = self._ForEachCpu('cat "$CPU/online"')
 129     # TODO(epenner): Investigate why file may be missing
 130     # (http://crbug.com/397118)
 131     return all(output.rstrip() == '1' and status == 0
 132                for (cpu, output, status) in results
 133                if cpu != 'cpu0')
 134
 135   def _ForceAllCpusOnline(self, force_online):
 136     """Enable all CPUs on a device.
 137
 138     Some vendors (or only Qualcomm?) hot-plug their CPUs, which can add noise
 139     to measurements:
 140     - In perf, samples are only taken for the CPUs that are online when the
 141       measurement is started.
 142     - The scaling governor can't be set for an offline CPU and frequency scaling
 143       on newly enabled CPUs adds noise to both perf and tracing measurements.
 144
 145     It appears Qualcomm is the only vendor that hot-plugs CPUs, and on Qualcomm
 146     this is done by "mpdecision".
 147
 148     """
 149     if self._have_mpdecision:
 150       script = 'stop mpdecision' if force_online else 'start mpdecision'
 151       self._device.RunShellCommand(script, check_return=True, as_root=True)
 152
 153     if not self._have_mpdecision and not self._AllCpusAreOnline():
 154       logging.warning('Unexpected cpu hot plugging detected.')
 155
 156     if force_online:
 157       self._ForEachCpu('echo 1 > "$CPU/online"')