tools/profile_chrome/ddms_controller.py

   1 # Copyright 2015 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import os
   6 import re
   7 import time
   8
   9 from profile_chrome import controllers
  10 from profile_chrome import util
  11
  12 _DDMS_SAMPLING_FREQUENCY_US = 100
  13
  14
  15 class DdmsController(controllers.BaseController):
  16   def __init__(self, device, package_info):
  17     controllers.BaseController.__init__(self)
  18     self._device = device
  19     self._package = package_info.package
  20     self._output_file = None
  21     self._supports_sampling = self._SupportsSampling()
  22
  23   def __repr__(self):
  24     return 'ddms profile'
  25
  26   def _SupportsSampling(self):
  27     for line in self._device.RunShellCommand('am --help'):
  28       if re.match(r'.*am profile start.*--sampling', line):
  29         return True
  30     return False
  31
  32   def StartTracing(self, _):
  33     self._output_file = (
  34         '/data/local/tmp/ddms-profile-%s' % util.GetTraceTimestamp())
  35     cmd = 'am profile start '
  36     if self._supports_sampling:
  37       cmd += '--sampling %d ' % _DDMS_SAMPLING_FREQUENCY_US
  38     cmd += '%s %s' % (self._package, self._output_file)
  39     self._device.RunShellCommand(cmd)
  40
  41   def StopTracing(self):
  42     self._device.RunShellCommand('am profile stop %s' % self._package)
  43
  44   def PullTrace(self):
  45     if not self._output_file:
  46       return None
  47
  48     # Wait for the trace file to get written.
  49     time.sleep(1)
  50
  51     host_file = os.path.join(
  52         os.path.curdir, os.path.basename(self._output_file))
  53     self._device.PullFile(self._output_file, host_file)
  54     return host_file