tools: Local tests for the speculative prefetch predictor.

tools/resource_prefetch_predictor/prefetch_benchmark.py

+#!/usr/bin/python
+#
+# Copyright 2016 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.
+
+"""Loads a web page with speculative prefetch, and collects loading metrics."""
+
+import argparse
+import logging
+import os
+import sys
+import time
+
+_SRC_PATH = os.path.abspath(os.path.join(
+    os.path.dirname(__file__), os.pardir, os.pardir))
+
+sys.path.append(os.path.join(
+    _SRC_PATH, 'tools', 'android', 'customtabs_benchmark', 'scripts'))
+import customtabs_benchmark
+import device_setup
+
+sys.path.append(os.path.join(_SRC_PATH, 'tools', 'android', 'loading'))
+from options import OPTIONS
+
+sys.path.append(os.path.join(_SRC_PATH, 'build', 'android'))
+import devil_chromium
+
+sys.path.append(os.path.join(_SRC_PATH, 'third_party', 'catapult', 'devil'))
+from devil.android.sdk import intent
+
+import prefetch_predictor_common
+
+
+_EXTERNAL_PREFETCH_FLAG = (
+    '--speculative-resource-prefetching=enabled-external-only')
+
+
+def _CreateArgumentParser():
+  """Creates and returns the argument parser."""
+  parser = argparse.ArgumentParser(
+      ('Loads a URL with the resource_prefetch_predictor and prints loading '
+       'metrics.'), parents=[OPTIONS.GetParentParser()])
+  parser.add_argument('--device', help='Device ID')
+  parser.add_argument('--database',
+                      help=('File containing the predictor database, as '
+                            'obtained from generate_database.py.'))
+  parser.add_argument('--url', help='URL to load.')
+  parser.add_argument('--prefetch_delay_ms',
+                      help='Prefetch delay in ms. -1 to disable prefetch.')
+  return parser
+
+
+def _Setup(device, database_filename):
+  """Sets up a device and returns an instance of RemoteChromeController."""
+  chrome_controller = prefetch_predictor_common.Setup(device, [''])
+  chrome_package = OPTIONS.ChromePackage()
+  device.ForceStop(chrome_package.package)
+  chrome_controller.ResetBrowserState()
+  device_database_filename = prefetch_predictor_common.DatabaseDevicePath()
+  owner = group = None
+
+  # Make sure that the speculative prefetch predictor is enabled to ensure
+  # that the disk database is re-created.
+  command_line_path = '/data/local/tmp/chrome-command-line'
+  with device_setup.FlagReplacer(
+      device, command_line_path, ['--disable-fre', _EXTERNAL_PREFETCH_FLAG]):
+    # Launch Chrome for the first time to recreate the local state.
+    launch_intent = intent.Intent(
+        action='android.intent.action.MAIN',
+        package=chrome_package.package,
+        activity=chrome_package.activity)
+    device.StartActivity(launch_intent, blocking=True)
+    time.sleep(5)
+    device.ForceStop(chrome_package.package)
+    assert device.FileExists(device_database_filename)
+    stats = device.StatPath(device_database_filename)
+    owner = stats['st_owner']
+    group = stats['st_group']
+  # Now push the database. Needs to be done after the first launch, otherwise
+  # the profile directory is owned by root. Also change the owner of the
+  # database, since adb push sets it to root.
+  database_content = open(database_filename, 'r').read()
+  device.WriteFile(device_database_filename, database_content, force_push=True)
+  command = 'chown %s:%s \'%s\'' % (owner, group, device_database_filename)
+  device.RunShellCommand(command, as_root=True)
+
+
+def _Go(device, url, prefetch_delay_ms):
+  disable_prefetch = prefetch_delay_ms == -1
+  chrome_args = (customtabs_benchmark.CHROME_ARGS
+                 + ['--trace-startup', '--trace-startup-duration=20'])

[pasko, 2016/11/30 12:53:46]

what do we use from --trace-startup?

[Benoit L, 2016/11/30 15:25:50]

Debugging. The trace is there, easy to look at it.
Do you want this removed?

[pasko, 2016/11/30 15:32:30]

no, not at all. I was wondering whether something relys on it, in which case I
wanted to know what, coz that would have been an interesting wtf. Can you just
drop a comment saying that this is not essential for operation of the benchmark,
just extra events for debugging?

+  if not disable_prefetch:
+    chrome_args.append(_EXTERNAL_PREFETCH_FLAG)
+  prefetch_mode = 'disabled' if disable_prefetch else 'speculative_prefetch'
+  result = customtabs_benchmark.RunOnce(
+      device, url, warmup=True, speculation_mode=prefetch_mode,
+      delay_to_may_launch_url=2000,
+      delay_to_launch_url=max(0, prefetch_delay_ms), cold=False,
+      chrome_args=chrome_args, reset_chrome_state=False)
+  print customtabs_benchmark.ParseResult(result)
+
+
+def main():
+  logging.basicConfig(level=logging.INFO)
+  devil_chromium.Initialize()
+
+  parser = _CreateArgumentParser()
+  args = parser.parse_args()
+  OPTIONS.SetParsedArgs(args)
+  device = prefetch_predictor_common.FindDevice(args.device)
+  if device is None:
+    logging.error('Could not find device: %s.', args.device)
+    sys.exit(1)
+
+  _Setup(device, args.database)
+  _Go(device, args.url, int(args.prefetch_delay_ms))
+
+
+if __name__ == '__main__':
+  main()