Refactor mojo_benchmark.

mojo/devtools/common/devtoolslib/benchmark.py

Index: mojo/devtools/common/devtoolslib/benchmark.py
diff --git a/mojo/devtools/common/devtoolslib/benchmark.py b/mojo/devtools/common/devtoolslib/benchmark.py
new file mode 100644
index 0000000000000000000000000000000000000000..3383dd44439a49cdc802db3c6bb8301a55e76650
--- /dev/null
+++ b/mojo/devtools/common/devtoolslib/benchmark.py
@@ -0,0 +1,103 @@
+# Copyright 2015 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.
+
+"""Logic that drives runs of the benchmarking mojo app and parses its output."""
+
+import os.path
+import re
+
+_BENCHMARK_APP = 'https://core.mojoapps.io/benchmark.mojo'
+
+# Additional time in seconds allocated per shell run to accommodate start-up.
+# The shell should terminate before hitting this time out, it is an error if it
+# doesn't.
+_EXTRA_TIMEOUT = 20
+
+_MEASUREMENT_RESULT_FORMAT = r"""
+^              # Beginning of the line.
+measurement:   # Hard-coded tag.
+\s+(\S+)       # Match measurement spec.
+\s+(\S+)       # Match measurement result.
+$              # End of the line.
+"""
+
+_MEASUREMENT_REGEX = re.compile(_MEASUREMENT_RESULT_FORMAT, re.VERBOSE)
+
+
+def _parse_measurement_results(output):
+  """Parses the measurement results present in the benchmark output and returns
+  the dictionary of correctly recognized and parsed results.
+  """
+  measurement_results = {}
+  output_lines = [line.strip() for line in output.split('\n')]
+  for line in output_lines:
+    match = re.match(_MEASUREMENT_REGEX, line)
+    if match:
+      measurement_spec = match.group(1)
+      measurement_result = match.group(2)
+      try:
+        measurement_results[measurement_spec] = float(measurement_result)
+      except ValueError:
+        pass
+  return measurement_results
+
+
+class Results(object):
+  """Holds results of a benchmark run."""
+
+  def __init__(self, succeeded, error_str, output):
+    self.succeeded = succeeded
+    self.error_str = error_str
+    self.output = output
+    self.measurements = None
+
+
+def run(shell, shell_args, app, duration_seconds, measurements, verbose,
+        android, output_file):
+  """Runs the given benchmark by running `benchmark.mojo` in mojo shell with
+  appropriate arguments and returns the produced output.
+
+  Returns:
+    A tuple of (succeeded, error_msg, output).
+  """
+  timeout = duration_seconds + _EXTRA_TIMEOUT
+  benchmark_args = []
+  benchmark_args.append('--app=' + app)
+  benchmark_args.append('--duration=' + str(duration_seconds))
+
+  device_output_file = None
+  if output_file:
+    if android:
+      device_output_file = os.path.join(shell.get_tmp_dir_path(), output_file)
+      benchmark_args.append('--trace-output=' + device_output_file)
+    else:
+      benchmark_args.append('--trace-output=' + output_file)
+
+  for measurement in measurements:
+    benchmark_args.append(measurement['spec'])
+
+  shell_args = list(shell_args)
+  shell_args.append(_BENCHMARK_APP)
+  shell_args.append('--force-offline-by-default')
+  shell_args.append('--args-for=%s %s' % (_BENCHMARK_APP,
+                                          ' '.join(benchmark_args)))
+
+  if verbose:
+    print 'shell arguments: ' + str(shell_args)
+  return_code, output, did_time_out = shell.run_and_get_output(
+      shell_args, timeout=timeout)
+
+  if did_time_out:
+    return Results(False, 'timed out', output)
+  if return_code:
+    return Results(False, 'return code: ' + str(return_code), output)
+
+  # Pull the trace file even if some measurements are missing, as it can be
+  # useful in debugging.
+  if device_output_file:
+    shell.pull_file(device_output_file, output_file, remove_original=True)
+
+  results = Results(True, None, output)
+  results.measurements = _parse_measurement_results(output)
+  return results