Add script to update perf_expectations.json.

tools/perf_expectations/make_expectations.py

Index: tools/perf_expectations/make_expectations.py
diff --git a/tools/perf_expectations/make_expectations.py b/tools/perf_expectations/make_expectations.py
new file mode 100755
index 0000000000000000000000000000000000000000..4fbee2075928382ba2101a3a096e3a070bab6387
--- /dev/null
+++ b/tools/perf_expectations/make_expectations.py
@@ -0,0 +1,239 @@
+#!/usr/bin/python
+# Copyright (c) 2010 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 math
+import optparse
+import re
+import simplejson
+import subprocess
+import sys
+import time
+import urllib2
+
+
+__version__ = '1.0'
+DEFAULT_EXPECTATIONS_FILE = 'perf_expectations.json'
+DEFAULT_VARIANCE = 0.05
+USAGE = ''
+
+
+def ReadFile(filename):
+  try:
+    file = open(filename, 'r')
+  except IOError, e:
+    print >> sys.stderr, ('I/O Error reading file %s(%s): %s' %
+                         (filename, e.errno, e.strerror))
+    raise e
+  if not file:
+    return None
+  contents = file.read()
+  file.close()
+  return contents
+
+
+def ConvertJsonIntoDict(string):
+  """Read a JSON string and convert its contents into a Python datatype."""
+  if len(string) == 0:
+    print >> sys.stderr, ('Error could not parse empty string')
+    raise Exception('JSON data missing')
+
+  try:
+    json = simplejson.loads(string)
+  except ValueError, e:
+    print >> sys.stderr, ('Error parsing string: "%s"' % string)
+    raise e
+  return json
+
+
+# Floating point representation of last time we fetched a URL.
+last_fetched_at = None
+def FetchUrlContents(url):
+  global last_fetched_at
+  if last_fetched_at and ((time.time() - last_fetched_at) <= 0.5):
+    # Sleep for half a second to avoid overloading the server.
+    time.sleep(0.5)
+  try:
+    last_fetched_at = time.time()
+    connection = urllib2.urlopen(url)
+  except urllib2.HTTPError, e:
+    if e.code == 404:
+      return None
+    raise e
+  text = connection.read().strip()
+  connection.close()
+  return text
+
+
+def WriteJson(filename, data, keys):
+  """Write a list of |keys| in |data| to the file specified in |filename|."""
+  try:
+    file = open(filename, 'w')
+  except IOError, e:
+    print >> sys.stderr, ('I/O Error writing file %s(%s): %s' %
+                          (filename, e.errno, e.strerror))
+    return False
+  jsondata = []
+  for key in keys:
+    rowdata = []
+    for subkey in ['reva', 'revb', 'improve', 'regress']:
+      if subkey in data[key]:
+        rowdata.append('"%s": %s' % (subkey, data[key][subkey]))
+    jsondata.append('"%s": {%s}' % (key, ', '.join(rowdata)))
+  jsondata.append('"load": true')
+  json = '{%s\n}' % ',\n '.join(jsondata)
+  file.write(json + '\n')
+  file.close()
+  return True
+
+
+def Main(args):
+  parser = optparse.OptionParser(usage=USAGE, version=__version__)
+  options, args = parser.parse_args(args)
+
+  # Get the list of summaries for a test.
+  base_url = 'http://build.chromium.org/f/chromium/perf'
+  perf = ConvertJsonIntoDict(ReadFile(DEFAULT_EXPECTATIONS_FILE))
+
+  # Fetch graphs.dat for this combination.
+  perfkeys = perf.keys()
+  # In perf_expectations.json, ignore the 'load' key.
+  perfkeys.remove('load')
+  perfkeys.sort()
+
+  write_new_expectations = False
+  for key in perfkeys:
+    value = perf[key]
+    variance = DEFAULT_VARIANCE
+
+    # Skip expectations that are missing a reva or revb.  We can't generate
+    # expectations for those.
+    if not(value.has_key('reva') and value.has_key('revb')):
+      print '%s (skipping, missing revision range)' % key
+      continue
+    revb = int(value['revb'])
+    reva = int(value['reva'])
+
+    # Ensure that reva is less than revb.
+    if reva > revb:
+      temp = reva
+      reva = revb
+      revb = temp
+
+    # Get the system/test/graph/tracename and reftracename for the current key.
+    matchData = re.match(r'^([^/]+)\/([^/]+)\/([^/]+)\/([^/]+)$', key)
+    if not matchData:
+      print '%s (skipping, cannot parse key)' % key
+      continue
+    system = matchData.group(1)
+    test = matchData.group(2)
+    graph = matchData.group(3)
+    tracename = matchData.group(4)
+    reftracename = tracename + '_ref'
+
+    # Create the summary_url and get the json data for that URL.
+    # FetchUrlContents() may sleep to avoid overloading the server with
+    # requests.
+    summary_url = '%s/%s/%s/%s-summary.dat' % (base_url, system, test, graph)
+    summaryjson = FetchUrlContents(summary_url)
+    if not summaryjson:
+      print '%s (skipping, missing json data)' % key
+      continue
+
+    summarylist = summaryjson.split('\n')
+    trace_values = {}
+    for trace in [tracename, reftracename]:
+      trace_values.setdefault(trace, {})
+
+    # Find the high and low values for each of the traces.
+    scanning = False
+    printed_error = False
+    for line in summarylist:
+      json = ConvertJsonIntoDict(line)
+      if int(json['rev']) <= revb:
+        scanning = True
+      if int(json['rev']) < reva:
+        break
+
+      # We found the upper revision in the range.  Scan for trace data until we
+      # find the lower revision in the range.
+      if scanning:
+        for trace in [tracename, reftracename]:
+          if trace not in json['traces']:
+            if not printed_error:
+              print '%s (error)' % key
+              printed_error = True
+            print '  trace %s missing' % trace
+            continue
+          if type(json['traces'][trace]) != type([]):
+            if not printed_error:
+              print '%s (error)' % key
+              printed_error = True
+            print '  trace %s format not recognized' % trace
+            continue
+          try:
+            tracevalue = float(json['traces'][trace][0])
+          except ValueError:
+            if not printed_error:
+              print '%s (error)' % key
+              printed_error = True
+            print '  trace %s value error: %s' % (
+                trace, str(json['traces'][trace][0]))
+            continue
+
+          for bound in ['high', 'low']:
+            trace_values[trace].setdefault(bound, tracevalue)
+
+          trace_values[trace]['high'] = max(trace_values[trace]['high'],
+                                            tracevalue)
+          trace_values[trace]['low'] = min(trace_values[trace]['low'],
+                                           tracevalue)
+
+    if 'high' not in trace_values[tracename]:
+      print '%s (skipping, no suitable traces matched)' % key
+      continue
+
+    # Calculate assuming high deltas are regressions and low deltas are
+    # improvements.
+    regress = (float(trace_values[tracename]['high']) -
+               float(trace_values[reftracename]['low']))
+    improve = (float(trace_values[tracename]['low']) -
+               float(trace_values[reftracename]['high']))
+    # If the existing values assume regressions are low deltas relative to
+    # improvements, swap our regress and improve.  This value must be a
+    # scores-like result.
+    if perf[key]['regress'] < perf[key]['improve']:
+      temp = regress
+      regress = improve
+      improve = temp
+    if regress < improve:
+      regress = int(math.floor(regress - abs(regress*variance)))
+      improve = int(math.ceil(improve + abs(improve*variance)))
+    else:
+      improve = int(math.floor(improve - abs(improve*variance)))
+      regress = int(math.ceil(regress + abs(regress*variance)))
+
+    if (perf[key]['regress'] == regress and perf[key]['improve'] == improve):
+      print '%s (no change)' % key
+      continue
+
+    write_new_expectations = True
+    print key
+    print '  before = %s' % perf[key]
+    print '  traces = %s' % trace_values
+    perf[key]['regress'] = regress
+    perf[key]['improve'] = improve
+    print '  after = %s' % perf[key]
+
+  if write_new_expectations:
+    print 'writing expectations... ',
+    WriteJson(DEFAULT_EXPECTATIONS_FILE, perf, perfkeys)
+    print 'done'
+  else:
+    print 'no updates made'
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv))