telemetry: Improve perf profiler

build/android/chrome_profiler/perf_controller.py

 # Copyright 2014 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 logging
 import os
 import subprocess
 import sys
 import tempfile
 
 from chrome_profiler import controllers
 
 from pylib import android_commands
 from pylib import constants
+from pylib.perf import perf_control
 
 sys.path.append(os.path.join(constants.DIR_SOURCE_ROOT,
                              'tools',
                              'telemetry'))
 try:
   # pylint: disable=F0401
   from telemetry.core.platform.profiler import android_profiling_helper
   from telemetry.util import support_binaries
 except ImportError:
   android_profiling_helper = None
@@ skipping 23 matching lines @@
         self._device.old_interface, prefix='perf_output')
     self._log_file = tempfile.TemporaryFile()
 
     device_param = (['-s', self._device.old_interface.GetDevice()]
                     if self._device.old_interface.GetDevice() else [])
     cmd = ['adb'] + device_param + \
           ['shell', perf_binary, 'record',
            '--output', self._output_file.name] + _PERF_OPTIONS
     if categories:
       cmd += ['--event', ','.join(categories)]
+    self._perf_control = perf_control.PerfControl(self._device)
+    self._perf_control.ForceAllCpusOnline(True)
     self._perf_process = subprocess.Popen(cmd,
                                           stdout=self._log_file,
                                           stderr=subprocess.STDOUT)
 
   def SignalAndWait(self):
     perf_pids = self._device.old_interface.ExtractPid('perf')
     self._device.old_interface.RunShellCommand(
         'kill -SIGINT ' + ' '.join(perf_pids))
     self._perf_process.wait()
+    self._perf_control.ForceAllCpusOnline(False)
 
   def _FailWithLog(self, msg):
     self._log_file.seek(0)
     log = self._log_file.read()
     raise RuntimeError('%s. Log output:\n%s' % (msg, log))
 
   def PullResult(self, output_path):
     if not self._device.old_interface.FileExistsOnDevice(
         self._output_file.name):
       self._FailWithLog('Perf recorded no data')
@@ skipping 74 matching lines @@
     perf_script_path = os.path.join(constants.DIR_SOURCE_ROOT,
         'tools', 'telemetry', 'telemetry', 'core', 'platform', 'profiler',
         'perf_vis', 'perf_to_tracing.py')
     json_file_name = os.path.basename(perf_profile)
     with open(os.devnull, 'w') as dev_null, \
         open(json_file_name, 'w') as json_file:
       cmd = [perfhost_path, 'script', '-s', perf_script_path, '-i',
              perf_profile, '--symfs', symfs_dir, '--kallsyms', kallsyms]
       subprocess.call(cmd, stdout=json_file, stderr=dev_null)
     return json_file_name