Telemetry: featurize tab_switching test for compressed swap performance

tools/perf/measurements/tab_switching.py

Index: tools/perf/measurements/tab_switching.py
diff --git a/tools/perf/measurements/tab_switching.py b/tools/perf/measurements/tab_switching.py
index 41290dc07de244e293b794f3c951467bfae2d0d0..b6fa5414162b5fa3a32e6b76f929ae2c8993576c 100644
--- a/tools/perf/measurements/tab_switching.py
+++ b/tools/perf/measurements/tab_switching.py
@@ -10,6 +10,7 @@ between when a tab was first requested to be shown, and when it was painted.
 Power usage is also measured.
 """
 
+import optparse

[aiolos (Not reviewing), 2015/04/03 18:16:39]

argparse should be used instead of optparse.

 import time
 
 from metrics import power
@@ -30,6 +31,26 @@ class TabSwitching(page_test.PageTest):
     self._first_page_in_pageset = True
     self._power_metric = None
 
+  @classmethod
+  def AddCommandLineArgs(cls, parser):

[aiolos (Not reviewing), 2015/04/03 18:16:39]

This shouldn't be specified via commandline arg.

+    group = optparse.OptionGroup(parser, 'Tab switching options')
+    group.add_option('--cycle-count',
+                     dest='cycle_count',
+                     default=1,
+                     type='int',
+                     help='Number of times the tab set is cycled through.')
+    # Use a high polling frequency throughout the test when checking for
+    # completion of a tab switch.  We may have to change this when running
+    # in a VM instrumented to get memory access statistics, because of the
+    # huge slowdown factor.
+    group.add_option('--poll-interval',
+                     dest='poll_interval',
+                     default=0.1,
+                     type='float',
+                     help='Poll interval when checking for completion '
+                     'of a tab switch.')
+    parser.add_option_group(group)
+
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs([
         '--enable-stats-collection-bindings'
@@ -77,18 +98,23 @@ class TabSwitching(page_test.PageTest):
         histogram_type, histogram_name, tab)
     prev_histogram = first_histogram
 
-    for i in xrange(len(tab.browser.tabs)):
-      t = tab.browser.tabs[i]
-      t.Activate()
-      def _IsDone():
-        cur_histogram = histogram_util.GetHistogram(
+    for _ in xrange(self.options.cycle_count):
+      for i in xrange(len(tab.browser.tabs)):
+        t = tab.browser.tabs[i]
+        t.Activate()
+        def _IsDone():
+          cur_histogram = histogram_util.GetHistogram(
+              histogram_type, histogram_name, tab)
+          diff_histogram = histogram_util.SubtractHistogram(
+              cur_histogram, prev_histogram)
+          return diff_histogram.count != 0
+        # Use a fixed poll interval when detecting the completion of a
+        # tab switch to reduce variance as the system gets slow, for
+        # instance because of swapping.
+        util.WaitFor(
+            _IsDone, 30, fixed_poll_interval=self.options.poll_interval)
+        prev_histogram = histogram_util.GetHistogram(
             histogram_type, histogram_name, tab)
-        diff_histogram = histogram_util.SubtractHistogram(
-            cur_histogram, prev_histogram)
-        return diff_histogram
-      util.WaitFor(_IsDone, 30)
-      prev_histogram = histogram_util.GetHistogram(
-          histogram_type, histogram_name, tab)
 
     last_histogram = histogram_util.GetHistogram(
         histogram_type, histogram_name, tab)