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