build/android/pylib/instrumentation/json_perf_parser.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
   6 """A helper module for parsing JSON objects from perf tests results."""
   7
   8 import json
   9
  10
  11 def GetAverageRunInfo(json_data, name):
  12   """Summarizes TraceEvent JSON data for performance metrics.
  13
  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   ]
  29
  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   ]
  44
  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.
  48
  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.
  61
  62   Raises:
  63     Exception: if entry contains invalid data.
  64   """
  65
  66   def EntryFilter(entry):
  67     return entry['cat'] == 'Java' and entry['name'] == name
  68   filtered_entries = filter(EntryFilter, json_data)
  69
  70   result = {}
  71
  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'] = ''
  81
  82   total_sum = 0
  83
  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'
  90
  91         def GetVal(entry):
  92           return entry['mem']
  93
  94         result['units'] = 'kb'
  95       elif 'ts' in entry:
  96         val_type = 'ts'
  97
  98         def GetVal(entry):
  99           return float(entry['ts']) / 1000.0
 100
 101         result['units'] = 'ms'
 102       else:
 103         raise Exception('Entry did not contain valid value info: %s' % entry)
 104
 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:
 129     result['average'] = total_sum / result['count']
 130
 131   return result
 132
 133
 134 def GetAverageRunInfoFromJSONString(json_string, name):
 135   """Returns the results from GetAverageRunInfo using a JSON string.
 136
 137   Args:
 138     json_string: The string containing JSON.
 139     name: The 'name' tag to filter on in the JSON file.
 140
 141   Returns:
 142     See GetAverageRunInfo Returns section.
 143   """
 144   return GetAverageRunInfo(json.loads(json_string), name)
 145
 146
 147 def GetAverageRunInfoFromFile(json_file, name):
 148   """Returns the results from GetAverageRunInfo using a JSON file.
 149
 150   Args:
 151     json_file: The path to a JSON file.
 152     name: The 'name' tag to filter on in the JSON file.
 153
 154   Returns:
 155     See GetAverageRunInfo Returns section.
 156   """
 157   with open(json_file, 'r') as f:
 158     data = f.read()
 159     perf = json.loads(data)
 160
 161   return GetAverageRunInfo(perf, name)