tools/perf/measurements/startup.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 import json
   6
   7 from telemetry.page import page_measurement
   8
   9 class Startup(page_measurement.PageMeasurement):
  10   """Performs a measurement of Chromium's startup performance.
  11
  12   This test must be invoked with either --warm or --cold on the command line. A
  13   cold start means none of the Chromium files are in the disk cache. A warm
  14   start assumes the OS has already cached much of Chromium's content. For warm
  15   tests, you should repeat the page set to ensure it's cached.
  16   """
  17
  18   HISTOGRAMS_TO_RECORD = {
  19     'messageloop_start_time' :
  20         'Startup.BrowserMessageLoopStartTimeFromMainEntry',
  21     'window_display_time' : 'Startup.BrowserWindowDisplay',
  22     'open_tabs_time' : 'Startup.BrowserOpenTabs'}
  23
  24   def __init__(self):
  25     super(Startup, self).__init__(needs_browser_restart_after_each_run=True)
  26
  27   def AddCommandLineOptions(self, parser):
  28     parser.add_option('--cold', action='store_true',
  29                       help='Clear the OS disk cache before performing the test')
  30     parser.add_option('--warm', action='store_true',
  31                       help='Start up with everything already cached')
  32
  33   def CustomizeBrowserOptions(self, options):
  34     # TODO: Once the bots start running benchmarks, enforce that either --warm
  35     # or --cold is explicitly specified.
  36     # assert options.warm != options.cold, \
  37     #     "You must specify either --warm or --cold"
  38     if options.cold:
  39       browser_options = options.browser_options
  40       browser_options.clear_sytem_cache_for_browser_and_profile_on_start = True
  41     else:
  42       self.discard_first_result = True
  43
  44     options.AppendExtraBrowserArgs([
  45         '--enable-stats-collection-bindings'
  46     ])
  47
  48   def MeasurePage(self, page, tab, results):
  49     get_histogram_js = 'statsCollectionController.getBrowserHistogram("%s")'
  50
  51     for display_name, histogram_name in self.HISTOGRAMS_TO_RECORD.iteritems():
  52       result = tab.EvaluateJavaScript(get_histogram_js % histogram_name)
  53       result = json.loads(result)
  54       measured_time = 0
  55
  56       if 'sum' in result:
  57         # For all the histograms logged here, there's a single entry so sum
  58         # is the exact value for that entry.
  59         measured_time = result['sum']
  60       elif 'buckets' in result:
  61         measured_time = \
  62             (result['buckets'][0]['high'] + result['buckets'][0]['low']) / 2
  63
  64       results.Add(display_name, 'ms', measured_time)