The Tor Browser: media/webrtc/trunk/build/android/pylib/perf_tests

     1 # Copyright (c) 2012 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.

     5 import re

     7 import android_commands

     8 import math

    10 # Valid values of result type.

    11 RESULT_TYPES = {'unimportant': 'RESULT ',

    12                 'default': '*RESULT ',

    13                 'informational': ''}

    16 def _EscapePerfResult(s):

    17   """Escapes |s| for use in a perf result."""

    18   # Colons (:) and equal signs (=) are not allowed, and we chose an arbitrary

    19   # limit of 40 chars.

    20   return re.sub(':|=', '_', s[:40])

    23 def PrintPerfResult(measurement, trace, values, units, result_type='default',

    24                     print_to_stdout=True):

    25   """Prints numerical data to stdout in the format required by perf tests.

    27   The string args may be empty but they must not contain any colons (:) or

    28   equals signs (=).

    30   Args:

    31     measurement: A description of the quantity being measured, e.g. "vm_peak".

    32     trace: A description of the particular data point, e.g. "reference".

    33     values: A list of numeric measured values.

    34     units: A description of the units of measure, e.g. "bytes".

    35     result_type: A  tri-state that accepts values of ['unimportant', 'default',

    36         'informational']. 'unimportant' prints RESULT, 'default' prints *RESULT

    37         and 'informational' prints nothing.

    38     print_to_stdout: If True, prints the output in stdout instead of returning

    39         the output to caller.

    41     Returns:

    42       String of the formated perf result.

    43   """

    44   assert result_type in RESULT_TYPES, 'result type: %s is invalid' % result_type

    46   assert isinstance(values, list)

    47   assert len(values)

    48   assert '/' not in measurement

    49   avg = None

    50   sd = None

    51   if len(values) > 1:

    52     try:

    53       value = '[%s]' % ','.join([str(v) for v in values])

    54       avg = sum([float(v) for v in values]) / len(values)

    55       sqdiffs = [(float(v) - avg) ** 2 for v in values]

    56       variance = sum(sqdiffs) / (len(values) - 1)

    57       sd = math.sqrt(variance)

    58     except ValueError:

    59       value = ", ".join(values)

    60   else:

    61     value = values[0]

    63   trace_name = _EscapePerfResult(trace)

    64   output = '%s%s: %s%s%s %s' % (

    65     RESULT_TYPES[result_type],

    66     _EscapePerfResult(measurement),

    67     trace_name,

    68     # Do not show equal sign if the trace is empty. Usually it happens when

    69     # measurement is enough clear to describe the result.

    70     '= ' if trace_name else '',

    71     value,

    72     units)

    73   if avg:

    74     output += '\nAvg %s: %f%s' % (measurement, avg, units)

    75   if sd:

    76     output += '\nSd  %s: %f%s' % (measurement, sd, units)

    77   if print_to_stdout:

    78     print output

    79   return output

    82 class PerfTestSetup(object):

    83   """Provides methods for setting up a device for perf testing."""

    84   _DROP_CACHES = '/proc/sys/vm/drop_caches'

    85   _SCALING_GOVERNOR = '/sys/devices/system/cpu/cpu%d/cpufreq/scaling_governor'

    87   def __init__(self, adb):

    88     self._adb = adb

    89     num_cpus = self._adb.GetFileContents('/sys/devices/system/cpu/online',

    90                                          log_result=False)

    91     assert num_cpus, 'Unable to find /sys/devices/system/cpu/online'

    92     self._num_cpus = int(num_cpus[0].split('-')[-1])

    93     self._original_scaling_governor = None

    95   def DropRamCaches(self):

    96     """Drops the filesystem ram caches for performance testing."""

    97     if not self._adb.IsRootEnabled():

    98       self._adb.EnableAdbRoot()

    99     self._adb.RunShellCommand('sync')

   100     self._adb.RunShellCommand('echo 3 > ' + PerfTestSetup._DROP_CACHES)

   102   def SetUp(self):

   103     """Sets up performance tests."""

   104     if not self._original_scaling_governor:

   105       self._original_scaling_governor = self._adb.GetFileContents(

   106           PerfTestSetup._SCALING_GOVERNOR % 0,

   107           log_result=False)[0]

   108       self._SetScalingGovernorInternal('performance')

   109     self.DropRamCaches()

   111   def TearDown(self):

   112     """Tears down performance tests."""

   113     if self._original_scaling_governor:

   114       self._SetScalingGovernorInternal(self._original_scaling_governor)

   115     self._original_scaling_governor = None

   117   def _SetScalingGovernorInternal(self, value):

   118     for cpu in range(self._num_cpus):

   119       self._adb.RunShellCommand(

   120           ('echo %s > ' + PerfTestSetup._SCALING_GOVERNOR) % (value, cpu))

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