tools/perf/metrics/loading.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 from metrics import Metric
   6 from telemetry.value import scalar
   7
   8 class LoadingMetric(Metric):
   9   """A metric for page loading time based entirely on window.performance"""
  10
  11   def Start(self, page, tab):
  12     raise NotImplementedError()
  13
  14   def Stop(self, page, tab):
  15     raise NotImplementedError()
  16
  17   def AddResults(self, tab, results):
  18     load_timings = tab.EvaluateJavaScript('window.performance.timing')
  19
  20     # NavigationStart relative markers in milliseconds.
  21     load_start = (
  22       float(load_timings['loadEventStart']) - load_timings['navigationStart'])
  23     results.AddValue(scalar.ScalarValue(
  24         results.current_page, 'load_start', 'ms', load_start))
  25
  26     dom_content_loaded_start = (
  27       float(load_timings['domContentLoadedEventStart']) -
  28       load_timings['navigationStart'])
  29     results.AddValue(scalar.ScalarValue(
  30         results.current_page, 'dom_content_loaded_start', 'ms',
  31         dom_content_loaded_start))
  32
  33     fetch_start = (
  34         float(load_timings['fetchStart']) - load_timings['navigationStart'])
  35     results.AddValue(scalar.ScalarValue(
  36         results.current_page, 'fetch_start', 'ms', fetch_start,
  37         important=False))
  38
  39     request_start = (
  40         float(load_timings['requestStart']) - load_timings['navigationStart'])
  41     results.AddValue(scalar.ScalarValue(
  42         results.current_page, 'request_start', 'ms', request_start,
  43         important=False))
  44
  45     # Phase measurements in milliseconds.
  46     domain_lookup_duration = (
  47         float(load_timings['domainLookupEnd']) -
  48         load_timings['domainLookupStart'])
  49     results.AddValue(scalar.ScalarValue(
  50         results.current_page, 'domain_lookup_duration', 'ms',
  51         domain_lookup_duration, important=False))
  52
  53     connect_duration = (
  54         float(load_timings['connectEnd']) - load_timings['connectStart'])
  55     results.AddValue(scalar.ScalarValue(
  56         results.current_page, 'connect_duration', 'ms', connect_duration,
  57         important=False))
  58
  59     request_duration = (
  60         float(load_timings['responseStart']) - load_timings['requestStart'])
  61     results.AddValue(scalar.ScalarValue(
  62         results.current_page, 'request_duration', 'ms', request_duration,
  63         important=False))
  64
  65     response_duration = (
  66         float(load_timings['responseEnd']) - load_timings['responseStart'])
  67     results.AddValue(scalar.ScalarValue(
  68         results.current_page, 'response_duration', 'ms', response_duration,
  69         important=False))