Fix bisect script to match a results with {mean, stddev} format.

tools/bisect-perf-regression.py

 #!/usr/bin/env python
 # Copyright (c) 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.
 
 """Performance Test Bisect Tool
 
 This script bisects a series of changelists using binary search. It starts at
 a bad revision where a performance metric has regressed, and asks for a last
 known-good revision. It will then binary search across this revision range by
@@ skipping 1927 matching lines @@
     """Attempts to parse a metric in the format RESULT <graph>: <trace>= ...
 
     Args:
       metric: The metric as a list of [<trace>, <value>] strings.
       text: The text to parse the metric values from.
 
     Returns:
       A list of floating point numbers found.
     """
     # Format is: RESULT <graph>: <trace>= <value> <units>
-    metric_formatted = re.escape('RESULT %s: %s=' % (metric[0], metric[1]))
+    metric_re = re.escape('RESULT %s: %s=' % (metric[0], metric[1]))
+
+    # The log will be parsed looking for format:
+    # <*>RESULT <graph_name>: <trace_name>= <value>
+    single_result_re = re.compile(
+        metric_re + '\s*(?P<VALUE>[-]?\d*(\.\d*)?)')
+
+    # The log will be parsed looking for format:
+    # <*>RESULT <graph_name>: <trace_name>= [<value>,value,value,...]
+    multi_results_re = re.compile(
+        metric_re + '\s*\[\s*(?P<VALUES>[-]?[\d\., ]+)\s*\]')
+
+    # The log will be parsed looking for format:
+    # <*>RESULT <graph_name>: <trace_name>= {<mean>, <std deviation>}
+    mean_stddev_re = re.compile(
+        metric_re +
+        '\s*\{\s*(?P<MEAN>[-]?\d*(\.\d*)?),\s*(?P<STDDEV>\d+(\.\d*)?)\s*\}')
 
     text_lines = text.split('\n')
     values_list = []
-
     for current_line in text_lines:
       # Parse the output from the performance test for the metric we're
       # interested in.
-      metric_re = metric_formatted +\
-                  "(\s)*(?P<values>[0-9]+(\.[0-9]*)?)"
-      metric_re = re.compile(metric_re)
-      regex_results = metric_re.search(current_line)
-
-      if not regex_results is None:
-        values_list += [regex_results.group('values')]
-      else:
-        metric_re = metric_formatted +\
-                    "(\s)*\[(\s)*(?P<values>[0-9,.]+)\]"
-        metric_re = re.compile(metric_re)
-        regex_results = metric_re.search(current_line)
-
-        if not regex_results is None:
-          metric_values = regex_results.group('values')
-
-          values_list += metric_values.split(',')
+      single_result_match = single_result_re.search(current_line)
+      multi_results_match = multi_results_re.search(current_line)
+      mean_stddev_match = mean_stddev_re.search(current_line)
+      if (not single_result_match is None and
+          single_result_match.group('VALUE')):
+        values_list += [single_result_match.group('VALUE')]
+      elif (not multi_results_match is None and
+            multi_results_match.group('VALUES')):
+        metric_values = multi_results_match.group('VALUES')
+        values_list += metric_values.split(',')
+      elif (not mean_stddev_match is None and
+            mean_stddev_match.group('MEAN')):
+        values_list += [mean_stddev_match.group('MEAN')]
 
     values_list = [float(v) for v in values_list if IsStringFloat(v)]
 
     # If the metric is times/t, we need to sum the timings in order to get
     # similar regression results as the try-bots.
     metrics_to_sum = [['times', 't'], ['times', 'page_load_time'],
         ['cold_times', 'page_load_time'], ['warm_times', 'page_load_time']]
 
     if metric in metrics_to_sum:
       if values_list:
@@ skipping 1910 matching lines @@
       # The perf dashboard scrapes the "results" step in order to comment on
       # bugs. If you change this, please update the perf dashboard as well.
       bisect_utils.OutputAnnotationStepStart('Results')
     print 'Error: %s' % e.message
     if opts.output_buildbot_annotations:
       bisect_utils.OutputAnnotationStepClosed()
   return 1
 
 if __name__ == '__main__':
   sys.exit(main())