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 histogram_util
  16 from metrics import power
  17 from telemetry.core import util
  18 from telemetry.page import page_test
  19 from telemetry.value import histogram
  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     power.PowerMetric.CustomizeBrowserOptions(options)
  38
  39   def WillStartBrowser(self, browser):
  40     self._first_page_in_pageset = True
  41     self._power_metric = power.PowerMetric(browser, TabSwitching.SAMPLE_TIME)
  42
  43   def TabForPage(self, page, browser):
  44     if self._first_page_in_pageset:
  45       # The initial browser window contains a single tab, navigate that tab
  46       # rather than creating a new one.
  47       self._first_page_in_pageset = False
  48       return browser.tabs[0]
  49
  50     return browser.tabs.New()
  51
  52   def StopBrowserAfterPage(self, browser, page):
  53     # Restart the browser after the last page in the pageset.
  54     return len(browser.tabs) >= len(page.page_set.pages)
  55
  56   def ValidateAndMeasurePage(self, page, tab, results):
  57     """On the last tab, cycle through each tab that was opened and then record
  58     a single histogram for the tab switching metric."""
  59     if len(tab.browser.tabs) != len(page.page_set.pages):
  60       return
  61
  62     # Measure power usage of tabs after quiescence.
  63     util.WaitFor(tab.HasReachedQuiescence, 60)
  64
  65     if tab.browser.platform.CanMonitorPower():
  66       self._power_metric.Start(page, tab)
  67       time.sleep(TabSwitching.SAMPLE_TIME)
  68       self._power_metric.Stop(page, tab)
  69       self._power_metric.AddResults(tab, results,)
  70
  71     histogram_name = 'MPArch.RWH_TabSwitchPaintDuration'
  72     histogram_type = histogram_util.BROWSER_HISTOGRAM
  73     display_name = 'MPArch_RWH_TabSwitchPaintDuration'
  74     first_histogram = histogram_util.GetHistogram(
  75         histogram_type, histogram_name, tab)
  76     prev_histogram = first_histogram
  77
  78     for i in xrange(len(tab.browser.tabs)):
  79       t = tab.browser.tabs[i]
  80       t.Activate()
  81       def _IsDone():
  82         cur_histogram = histogram_util.GetHistogram(
  83             histogram_type, histogram_name, tab)
  84         diff_histogram = histogram_util.SubtractHistogram(
  85             cur_histogram, prev_histogram)
  86         return diff_histogram
  87       util.WaitFor(_IsDone, 30)
  88       prev_histogram = histogram_util.GetHistogram(
  89           histogram_type, histogram_name, tab)
  90
  91     last_histogram = histogram_util.GetHistogram(
  92         histogram_type, histogram_name, tab)
  93     diff_histogram = histogram_util.SubtractHistogram(last_histogram,
  94         first_histogram)
  95
  96     results.AddSummaryValue(
  97         histogram.HistogramValue(None, display_name, '',
  98                                  raw_value_json=diff_histogram,
  99                                  important=False))