Move memory-related histogram data collection to metrics/memory.py

tools/perf/metrics/memory.py

 # Copyright 2013 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.
 
 import sys
 
 from metrics import Metric
 from metrics import histogram
 
 _HISTOGRAMS = [
@@ skipping 23 matching lines @@
     self._histogram_start_values = dict()
     self._histogram_delta_values = dict()
 
   def Start(self, page, tab):
     """Start the per-page preparation for this metric.
 
     Here, this consists of recording the start value of all the histograms.
     """
     for h in _HISTOGRAMS:
       histogram_data = histogram.GetHistogramData(h['type'], h['name'], tab)
+      # Histogram data may not be available

[qyearsley, 2013/08/12 20:57:48]

Not sure if it's best not to repeat this comment below, but it seems that
there's no harm in it.

       if not histogram_data:
         continue
       self._histogram_start_values[h['name']] = histogram_data
 
   def Stop(self, page, tab):
     """Prepare the results for this page.
 
     The results are the differences between the current histogram values
     and the values when Start() was called.
     """
     assert self._histogram_start_values, 'Must call Start() first'
     for h in _HISTOGRAMS:
+      # Histogram data may not be available
+      if h['name'] not in self._histogram_start_values:
+        continue
       histogram_data = histogram.GetHistogramData(h['type'], h['name'], tab)
-      self._histogram_delta_values = histogram.SubtractHistogram(
+      self._histogram_delta_values[h['name']] = histogram.SubtractHistogram(

[qyearsley, 2013/08/12 20:57:48]

I forgot to use self._histogram_delta_values as a dictionary here before.

           histogram_data, self._histogram_start_values[h['name']])

[qyearsley, 2013/08/12 20:57:48]

Here (and in AddResults) I'm assuming that if histogram data was set before for
a particular histogram name, then histogram.GetHistogramData will return new
histogram data; I think this is a reasonable assumption.

 
   def AddResults(self, tab, results):
     """Add results for this page to the results object."""
     assert self._histogram_delta_values, 'Must call Stop() first'
     for h in _HISTOGRAMS:
+      # Histogram data may not be available
+      if h['name'] not in self._histogram_delta_values:
+        continue
       histogram_data = self._histogram_delta_values[h['name']]
       results.Add(h['name'], h['units'], histogram_data,
                   data_type='unimportant-histogram')
 
   def AddSummaryResults(self, results):
     """Add summary (overall) results to the results object."""
     self._end_memory_stats = self._browser.memory_stats
     if not self._end_memory_stats['Browser']:
       return
 
@@ skipping 38 matching lines @@
     AddSummariesForProcessTypes(['Gpu'], 'gpu')
     AddSummariesForProcessTypes(['Browser', 'Renderer', 'Gpu'], 'total')
 
     end_commit_charge = self._end_memory_stats['SystemCommitCharge']
     commit_charge_difference = end_commit_charge - self._start_commit_charge
     results.AddSummary('commit_charge', 'kb', commit_charge_difference,
                        data_type='unimportant')
     results.AddSummary('processes', 'count', self._memory_stats['ProcessCount'],
                        data_type='unimportant')