Telemetry / Memory benchmark fix: Separate histograms for different tests.

tools/perf/perf_tools/memory_benchmark.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 from telemetry import multi_page_benchmark
+from telemetry import util
 
 MEMORY_HISTOGRAMS = [
     {'name': 'V8.MemoryExternalFragmentationTotal', 'units': 'percent'},
     {'name': 'V8.MemoryHeapSampleTotalCommitted', 'units': 'kb'},
     {'name': 'V8.MemoryHeapSampleTotalUsed', 'units': 'kb'},
     {'name': 'Memory.RendererUsed', 'units': 'kb'}]
 
 BROWSER_MEMORY_HISTOGRAMS =  [
     {'name': 'Memory.BrowserUsed', 'units': 'kb'}]
 
 class MemoryBenchmark(multi_page_benchmark.MultiPageBenchmark):
   def __init__(self):
     super(MemoryBenchmark, self).__init__('stress_memory')
+    self._baselines = dict()
+
+  def WillNavigateToPage(self, page, tab):

[nduca, 2013/02/12 18:33:15]

not sure i'd call this baselines. The word 'Baselines' usually is used in the
context of test expectations. These are start values, more like.

[marja, 2013/02/13 16:09:30]

Done.

+    for histogram in MEMORY_HISTOGRAMS:
+      name = histogram['name']

[nduca, 2013/02/12 18:33:15]

How about a histogram measurement object?

HistogramMeasurement(hsto name)

willmeasure:
m.start()

didmeasure:
m.getvalue()

[marja, 2013/02/13 16:09:30]

Done.

+      data = self._GetHistogramFromDomAutomation(tab, 'getHistogram', name)
+      if data:
+        self._baselines[page.url + name] = data
+    for histogram in BROWSER_MEMORY_HISTOGRAMS:
+      name = histogram['name']
+      data = self._GetHistogramFromDomAutomation(tab, 'getBrowserHistogram',
+                                                 name)
+      if data:
+        self._baselines[page.url + name] = data
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArg('--dom-automation')
     # For a hard-coded set of Google pages (such as GMail), we produce custom
     # memory histograms (V8.Something_gmail) instead of the generic histograms
     # (V8.Something), if we detect that a renderer is only rendering this page
     # and no other pages. For this test, we need to disable histogram
     # customizing, so that we get the same generic histograms produced for all
     # pages.
     options.AppendExtraBrowserArg('--disable-histogram-customizer')
     options.AppendExtraBrowserArg('--memory-metrics')
 
   def CanRunForPage(self, page):
     return hasattr(page, 'stress_memory')
 
   def MeasurePage(self, page, tab, results):
     for histogram in MEMORY_HISTOGRAMS:
-      self._GetHistogramFromDomAutomation(tab, 'getHistogram', histogram,
-                                          results)
+      name = histogram['name']
+      data = self._GetHistogramFromDomAutomation(tab, 'getHistogram', name)
+      self._AddHistogramResult(histogram, page, data, results)
     for histogram in BROWSER_MEMORY_HISTOGRAMS:
-      self._GetHistogramFromDomAutomation(tab, 'getBrowserHistogram', histogram,
-                                          results)
+      name = histogram['name']
+      data = self._GetHistogramFromDomAutomation(tab, 'getBrowserHistogram',
+                                                 name)
+      self._AddHistogramResult(histogram, page, data, results)
 
-  def _GetHistogramFromDomAutomation(self, tab, func, histogram, results):
-    name = histogram['name']
+  def _GetHistogramFromDomAutomation(self, tab, func, name):
     js = ('window.domAutomationController.%s ? '
           'window.domAutomationController.%s("%s") : ""' % (func, func, name))
-    data = tab.EvaluateJavaScript(js)
-    if data:
-      results.Add(name.replace('.', '_'), histogram['units'], data,
-                  data_type='histogram')
+    return tab.EvaluateJavaScript(js)
+
+  def _AddHistogramResult(self, histogram, page, data, results):
+    if not data:
+      return
+    name = histogram['name']
+    if page.url + name not in self._baselines:
+      return
+    results.Add(name.replace('.', '_'), histogram['units'],
+                util.SubtractHistogram(data, self._baselines[page.url + name]),
+                data_type='histogram')