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 """
  11
  12 import time
  13
  14 from metrics import cpu
  15 from metrics import histogram_util
  16 from telemetry.core import util
  17 from telemetry.page import page_measurement
  18 from telemetry.page import page_runner
  19
  20 # TODO: Revisit this test once multitab support is finalized.
  21
  22 class TabSwitching(page_measurement.PageMeasurement):
  23   def __init__(self):
  24     super(TabSwitching, self).__init__()
  25     self._cpu_metric = None
  26
  27   def CustomizeBrowserOptions(self, options):
  28     options.AppendExtraBrowserArgs([
  29         '--enable-stats-collection-bindings'
  30     ])
  31
  32   def DidStartBrowser(self, browser):
  33     self._cpu_metric = cpu.Cpu(browser)
  34
  35   def CanRunForPage(self, page):
  36     return not page.page_set.pages.index(page)
  37
  38   def DidNavigateToPage(self, page, tab):
  39     for i in xrange(1, len(page.page_set.pages)):
  40       t = tab.browser.tabs.New()
  41
  42       # We create a test_stub to be able to call 'navigate_steps' on pages
  43       test_stub = page_measurement.PageMeasurement()
  44       page_state = page_runner.PageState()
  45       page_state.PreparePage(page.page_set.pages[i], t)
  46       page_state.ImplicitPageNavigation(page.page_set.pages[i], t, test_stub)
  47
  48     # Start tracking cpu load after all pages have loaded.
  49     self._cpu_metric.Start(page, tab)
  50
  51   def MeasurePage(self, page, tab, results):
  52     """Although this is called MeasurePage, we're actually using this function
  53     to cycle through each tab that was opened via DidNavigateToPage and
  54     then record a single histogram for the tab switching metric.
  55     """
  56     # Calculate the idle cpu load before any actions are done.
  57     time.sleep(.5)
  58     self._cpu_metric.Stop(page, tab)
  59     self._cpu_metric.AddResults(tab, results,
  60                                 'idle_cpu_utilization')
  61
  62     histogram_name = 'MPArch.RWH_TabSwitchPaintDuration'
  63     histogram_type = histogram_util.BROWSER_HISTOGRAM
  64     first_histogram = histogram_util.GetHistogram(
  65         histogram_type, histogram_name, tab)
  66     prev_histogram = first_histogram
  67
  68     for i in xrange(len(tab.browser.tabs)):
  69       t = tab.browser.tabs[i]
  70       t.Activate()
  71       def _IsDone():
  72         cur_histogram = histogram_util.GetHistogram(
  73             histogram_type, histogram_name, tab)
  74         diff_histogram = histogram_util.SubtractHistogram(
  75             cur_histogram, prev_histogram)
  76         return diff_histogram
  77       util.WaitFor(_IsDone, 30)
  78       prev_histogram = histogram_util.GetHistogram(
  79           histogram_type, histogram_name, tab)
  80
  81     last_histogram = histogram_util.GetHistogram(
  82         histogram_type, histogram_name, tab)
  83     diff_histogram = histogram_util.SubtractHistogram(last_histogram,
  84         first_histogram)
  85
  86     results.AddSummary(histogram_name, '', diff_histogram,
  87         data_type='unimportant-histogram')