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

     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.

     6 """A helper module for parsing JSON objects from perf tests results."""

     8 import json

    11 def GetAverageRunInfo(json_data, name):

    12   """Summarizes TraceEvent JSON data for performance metrics.

    14   Example JSON Inputs (More tags can be added but these are required):

    15   Measuring Duration:

    16   [

    17     { "cat": "Java",

    18       "ts": 10000000000,

    19       "ph": "S",

    20       "name": "TestTrace"

    21     },

    22     { "cat": "Java",

    23       "ts": 10000004000,

    24       "ph": "F",

    25       "name": "TestTrace"

    26     },

    27     ...

    28   ]

    30   Measuring Call Frequency (FPS):

    31   [

    32     { "cat": "Java",

    33       "ts": 10000000000,

    34       "ph": "I",

    35       "name": "TestTraceFPS"

    36     },

    37     { "cat": "Java",

    38       "ts": 10000004000,

    39       "ph": "I",

    40       "name": "TestTraceFPS"

    41     },

    42     ...

    43   ]

    45   Args:

    46     json_data: A list of dictonaries each representing a JSON object.

    47     name: The 'name' tag to filter on in the JSON file.

    49   Returns:

    50     A dictionary of result data with the following tags:

    51       min: The minimum value tracked.

    52       max: The maximum value tracked.

    53       average: The average of all the values tracked.

    54       count: The number of times the category/name pair was tracked.

    55       type: The type of tracking ('Instant' for instant tags and 'Span' for

    56             begin/end tags.

    57       category: The passed in category filter.

    58       name: The passed in name filter.

    59       data_points: A list of all of the times used to generate this data.

    60       units: The units for the values being reported.

    62   Raises:

    63     Exception: if entry contains invalid data.

    64   """

    66   def EntryFilter(entry):

    67     return entry['cat'] == 'Java' and entry['name'] == name

    68   filtered_entries = filter(EntryFilter, json_data)

    70   result = {}

    72   result['min'] = -1

    73   result['max'] = -1

    74   result['average'] = 0

    75   result['count'] = 0

    76   result['type'] = 'Unknown'

    77   result['category'] = 'Java'

    78   result['name'] = name

    79   result['data_points'] = []

    80   result['units'] = ''

    82   total_sum = 0

    84   last_val = 0

    85   val_type = None

    86   for entry in filtered_entries:

    87     if not val_type:

    88       if 'mem' in entry:

    89         val_type = 'mem'

    91         def GetVal(entry):

    92           return entry['mem']

    94         result['units'] = 'kb'

    95       elif 'ts' in entry:

    96         val_type = 'ts'

    98         def GetVal(entry):

    99           return float(entry['ts']) / 1000.0

   101         result['units'] = 'ms'

   102       else:

   103         raise Exception('Entry did not contain valid value info: %s' % entry)

   105     if not val_type in entry:

   106       raise Exception('Entry did not contain expected value type "%s" '

   107                       'information: %s' % (val_type, entry))

   108     val = GetVal(entry)

   109     if (entry['ph'] == 'S' and

   110         (result['type'] == 'Unknown' or result['type'] == 'Span')):

   111       result['type'] = 'Span'

   112       last_val = val

   113     elif ((entry['ph'] == 'F' and result['type'] == 'Span') or

   114           (entry['ph'] == 'I' and (result['type'] == 'Unknown' or

   115                                    result['type'] == 'Instant'))):

   116       if last_val > 0:

   117         delta = val - last_val

   118         if result['min'] == -1 or result['min'] > delta:

   119           result['min'] = delta

   120         if result['max'] == -1 or result['max'] < delta:

   121           result['max'] = delta

   122         total_sum += delta

   123         result['count'] += 1

   124         result['data_points'].append(delta)

   125       if entry['ph'] == 'I':

   126         result['type'] = 'Instant'

   127         last_val = val

   128   if result['count'] > 0: result['average'] = total_sum / result['count']

   130   return result

   133 def GetAverageRunInfoFromJSONString(json_string, name):

   134   """Returns the results from GetAverageRunInfo using a JSON string.

   136   Args:

   137     json_string: The string containing JSON.

   138     name: The 'name' tag to filter on in the JSON file.

   140   Returns:

   141     See GetAverageRunInfo Returns section.

   142   """

   143   return GetAverageRunInfo(json.loads(json_string), name)

   146 def GetAverageRunInfoFromFile(json_file, name):

   147   """Returns the results from GetAverageRunInfo using a JSON file.

   149   Args:

   150     json_file: The path to a JSON file.

   151     name: The 'name' tag to filter on in the JSON file.

   153   Returns:

   154     See GetAverageRunInfo Returns section.

   155   """

   156   with open(json_file, 'r') as f:

   157     data = f.read()

   158     perf = json.loads(data)

   160   return GetAverageRunInfo(perf, name)

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