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.
6 """A helper module for parsing JSON objects from perf tests results."""
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):
30 Measuring Call Frequency (FPS):
35 "name": "TestTraceFPS"
40 "name": "TestTraceFPS"
46 json_data: A list of dictonaries each representing a JSON object.
47 name: The 'name' tag to filter on in the JSON file.
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
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.
63 Exception: if entry contains invalid data.
66 def EntryFilter(entry):
67 return entry['cat'] == 'Java' and entry['name'] == name
68 filtered_entries = filter(EntryFilter, json_data)
76 result['type'] = 'Unknown'
77 result['category'] = 'Java'
79 result['data_points'] = []
86 for entry in filtered_entries:
94 result['units'] = 'kb'
99 return float(entry['ts']) / 1000.0
101 result['units'] = 'ms'
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))
109 if (entry['ph'] == 'S' and
110 (result['type'] == 'Unknown' or result['type'] == 'Span')):
111 result['type'] = 'Span'
113 elif ((entry['ph'] == 'F' and result['type'] == 'Span') or
114 (entry['ph'] == 'I' and (result['type'] == 'Unknown' or
115 result['type'] == 'Instant'))):
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
124 result['data_points'].append(delta)
125 if entry['ph'] == 'I':
126 result['type'] = 'Instant'
128 if result['count'] > 0: result['average'] = total_sum / result['count']
133 def GetAverageRunInfoFromJSONString(json_string, name):
134 """Returns the results from GetAverageRunInfo using a JSON string.
137 json_string: The string containing JSON.
138 name: The 'name' tag to filter on in the JSON file.
141 See GetAverageRunInfo Returns section.
143 return GetAverageRunInfo(json.loads(json_string), name)
146 def GetAverageRunInfoFromFile(json_file, name):
147 """Returns the results from GetAverageRunInfo using a JSON file.
150 json_file: The path to a JSON file.
151 name: The 'name' tag to filter on in the JSON file.
154 See GetAverageRunInfo Returns section.
156 with open(json_file, 'r') as f:
158 perf = json.loads(data)
160 return GetAverageRunInfo(perf, name)