tools/perf/measurements/tab_switching.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 """The tab switching measurement.
   6
   7 This measurement opens pages in different tabs. After all the tabs have opened,
   8 it cycles through each tab in sequence, and records a histogram of the time
   9 between when a tab was first requested to be shown, and when it was painted.
  10 Power usage is also measured.
  11 """
  12
  13 import time
  14
  15 from metrics import power
  16 from telemetry.core import util
  17 from telemetry.page import page_test
  18 from telemetry.value import histogram
  19 from telemetry.value import histogram_util
  20
  21 # TODO: Revisit this test once multitab support is finalized.
  22
  23 class TabSwitching(page_test.PageTest):
  24
  25   # Amount of time to measure, in seconds.
  26   SAMPLE_TIME = 30
  27
  28   def __init__(self):
  29     super(TabSwitching, self).__init__()
  30     self._first_page_in_pageset = True
  31     self._power_metric = None
  32
  33   def CustomizeBrowserOptions(self, options):
  34     options.AppendExtraBrowserArgs([
  35         '--enable-stats-collection-bindings'
  36     ])
  37     # Enable background networking so we can test its impact on power usage.
  38     options.disable_background_networking = False
  39     power.PowerMetric.CustomizeBrowserOptions(options)
  40
  41   def WillStartBrowser(self, platform):
  42     self._first_page_in_pageset = True
  43     self._power_metric = power.PowerMetric(platform, TabSwitching.SAMPLE_TIME)
  44
  45   def TabForPage(self, page, browser):
  46     if self._first_page_in_pageset:
  47       # The initial browser window contains a single tab, navigate that tab
  48       # rather than creating a new one.
  49       self._first_page_in_pageset = False
  50       return browser.tabs[0]
  51
  52     return browser.tabs.New()
  53
  54   def StopBrowserAfterPage(self, browser, page):
  55     # Restart the browser after the last page in the pageset.
  56     return len(browser.tabs) >= len(page.page_set.pages)
  57
  58   def ValidateAndMeasurePage(self, page, tab, results):
  59     """On the last tab, cycle through each tab that was opened and then record
  60     a single histogram for the tab switching metric."""
  61     if len(tab.browser.tabs) != len(page.page_set.pages):
  62       return
  63
  64     # Measure power usage of tabs after quiescence.
  65     util.WaitFor(tab.HasReachedQuiescence, 60)
  66
  67     if tab.browser.platform.CanMonitorPower():
  68       self._power_metric.Start(page, tab)
  69       time.sleep(TabSwitching.SAMPLE_TIME)
  70       self._power_metric.Stop(page, tab)
  71       self._power_metric.AddResults(tab, results,)
  72
  73     histogram_name = 'MPArch.RWH_TabSwitchPaintDuration'
  74     histogram_type = histogram_util.BROWSER_HISTOGRAM
  75     display_name = 'MPArch_RWH_TabSwitchPaintDuration'
  76     first_histogram = histogram_util.GetHistogram(
  77         histogram_type, histogram_name, tab)
  78     prev_histogram = first_histogram
  79
  80     for i in xrange(len(tab.browser.tabs)):
  81       t = tab.browser.tabs[i]
  82       t.Activate()
  83       def _IsDone():
  84         cur_histogram = histogram_util.GetHistogram(
  85             histogram_type, histogram_name, tab)
  86         diff_histogram = histogram_util.SubtractHistogram(
  87             cur_histogram, prev_histogram)
  88         return diff_histogram
  89       util.WaitFor(_IsDone, 30)
  90       prev_histogram = histogram_util.GetHistogram(
  91           histogram_type, histogram_name, tab)
  92
  93     last_histogram = histogram_util.GetHistogram(
  94         histogram_type, histogram_name, tab)
  95     diff_histogram = histogram_util.SubtractHistogram(last_histogram,
  96         first_histogram)
  97
  98     results.AddSummaryValue(
  99         histogram.HistogramValue(None, display_name, 'ms',
 100                                  raw_value_json=diff_histogram,
 101                                  important=False))