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build/util/lib/common/perf_tests_results_helper.py

Index: build/util/lib/common/perf_tests_results_helper.py
diff --git a/build/util/lib/common/perf_tests_results_helper.py b/build/util/lib/common/perf_tests_results_helper.py
new file mode 100644
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+++ b/build/util/lib/common/perf_tests_results_helper.py
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+# 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 re
+import sys
+
+import json
+import logging
+import math
+
+import perf_result_data_type
+
+
+# Mapping from result type to test output
+RESULT_TYPES = {perf_result_data_type.UNIMPORTANT: 'RESULT ',
+                perf_result_data_type.DEFAULT: '*RESULT ',
+                perf_result_data_type.INFORMATIONAL: '',
+                perf_result_data_type.UNIMPORTANT_HISTOGRAM: 'HISTOGRAM ',
+                perf_result_data_type.HISTOGRAM: '*HISTOGRAM '}
+
+
+def _EscapePerfResult(s):
+  """Escapes |s| for use in a perf result."""
+  return re.sub('[\:|=/#&,]', '_', s)
+
+
+def FlattenList(values):
+  """Returns a simple list without sub-lists."""
+  ret = []
+  for entry in values:
+    if isinstance(entry, list):
+      ret.extend(FlattenList(entry))
+    else:
+      ret.append(entry)
+  return ret
+
+
+def GeomMeanAndStdDevFromHistogram(histogram_json):
+  histogram = json.loads(histogram_json)
+  # Handle empty histograms gracefully.
+  if not 'buckets' in histogram:
+    return 0.0, 0.0
+  count = 0
+  sum_of_logs = 0
+  for bucket in histogram['buckets']:
+    if 'high' in bucket:
+      bucket['mean'] = (bucket['low'] + bucket['high']) / 2.0
+    else:
+      bucket['mean'] = bucket['low']
+    if bucket['mean'] > 0:
+      sum_of_logs += math.log(bucket['mean']) * bucket['count']
+      count += bucket['count']
+
+  if count == 0:
+    return 0.0, 0.0
+
+  sum_of_squares = 0
+  geom_mean = math.exp(sum_of_logs / count)
+  for bucket in histogram['buckets']:
+    if bucket['mean'] > 0:
+      sum_of_squares += (bucket['mean'] - geom_mean) ** 2 * bucket['count']
+  return geom_mean, math.sqrt(sum_of_squares / count)
+
+
+def _ValueToString(v):
+  # Special case for floats so we don't print using scientific notation.
+  if isinstance(v, float):
+    return '%f' % v
+  else:
+    return str(v)
+
+
+def _MeanAndStdDevFromList(values):
+  avg = None
+  sd = None
+  if len(values) > 1:
+    try:
+      value = '[%s]' % ','.join([_ValueToString(v) for v in values])
+      avg = sum([float(v) for v in values]) / len(values)
+      sqdiffs = [(float(v) - avg) ** 2 for v in values]
+      variance = sum(sqdiffs) / (len(values) - 1)
+      sd = math.sqrt(variance)
+    except ValueError:
+      value = ', '.join(values)
+  else:
+    value = values[0]
+  return value, avg, sd
+
+
+def PrintPages(page_list):
+  """Prints list of pages to stdout in the format required by perf tests."""
+  print 'Pages: [%s]' % ','.join([_EscapePerfResult(p) for p in page_list])
+
+
+def PrintPerfResult(measurement, trace, values, units,
+                    result_type=perf_result_data_type.DEFAULT,
+                    print_to_stdout=True):
+  """Prints numerical data to stdout in the format required by perf tests.
+
+  The string args may be empty but they must not contain any colons (:) or
+  equals signs (=).
+  This is parsed by the buildbot using:
+  http://src.chromium.org/viewvc/chrome/trunk/tools/build/scripts/slave/process_log_utils.py
+
+  Args:
+    measurement: A description of the quantity being measured, e.g. "vm_peak".
+        On the dashboard, this maps to a particular graph. Mandatory.
+    trace: A description of the particular data point, e.g. "reference".
+        On the dashboard, this maps to a particular "line" in the graph.
+        Mandatory.
+    values: A list of numeric measured values. An N-dimensional list will be
+        flattened and treated as a simple list.
+    units: A description of the units of measure, e.g. "bytes".
+    result_type: Accepts values of perf_result_data_type.ALL_TYPES.
+    print_to_stdout: If True, prints the output in stdout instead of returning
+        the output to caller.
+
+    Returns:
+      String of the formated perf result.
+  """
+  assert perf_result_data_type.IsValidType(result_type), \
+         'result type: %s is invalid' % result_type
+
+  trace_name = _EscapePerfResult(trace)
+
+  if (result_type == perf_result_data_type.UNIMPORTANT or
+      result_type == perf_result_data_type.DEFAULT or
+      result_type == perf_result_data_type.INFORMATIONAL):
+    assert isinstance(values, list)
+    assert '/' not in measurement
+    flattened_values = FlattenList(values)
+    assert len(flattened_values)
+    value, avg, sd = _MeanAndStdDevFromList(flattened_values)
+    output = '%s%s: %s%s%s %s' % (
+        RESULT_TYPES[result_type],
+        _EscapePerfResult(measurement),
+        trace_name,
+        # Do not show equal sign if the trace is empty. Usually it happens when
+        # measurement is enough clear to describe the result.
+        '= ' if trace_name else '',
+        value,
+        units)
+  else:
+    assert perf_result_data_type.IsHistogram(result_type)
+    assert isinstance(values, list)
+    # The histograms can only be printed individually, there's no computation
+    # across different histograms.
+    assert len(values) == 1
+    value = values[0]
+    output = '%s%s: %s= %s %s' % (
+        RESULT_TYPES[result_type],
+        _EscapePerfResult(measurement),
+        trace_name,
+        value,
+        units)
+    avg, sd = GeomMeanAndStdDevFromHistogram(value)
+
+  if avg:
+    output += '\nAvg %s: %f%s' % (measurement, avg, units)
+  if sd:
+    output += '\nSd  %s: %f%s' % (measurement, sd, units)
+  if print_to_stdout:
+    print output
+    sys.stdout.flush()
+  return output