1 # Copyright 2014 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 threading 6 import zlib 7 8 from devil.utils import cmd_helper 9 10 from profile_chrome import controllers 11 from profile_chrome import util 12 13 14 _SYSTRACE_OPTIONS = [ 15 # Compress the trace before sending it over USB. 16 '-z', 17 # Use a large trace buffer to increase the polling interval. 18 '-b', '16384' 19 ] 20 21 # Interval in seconds for sampling systrace data. 22 _SYSTRACE_INTERVAL = 15 23 24 _TRACING_ON_PATH = '/sys/kernel/debug/tracing/tracing_on' 25 26 27 class SystraceController(controllers.BaseController): 28 def __init__(self, device, categories, ring_buffer): 29 controllers.BaseController.__init__(self) 30 self._device = device 31 self._categories = categories 32 self._ring_buffer = ring_buffer 33 self._done = threading.Event() 34 self._thread = None 35 self._trace_data = None 36 37 def __repr__(self): 38 return 'systrace' 39 40 @staticmethod 41 def GetCategories(device): 42 return device.RunShellCommand('atrace --list_categories') 43 44 def StartTracing(self, _): 45 self._thread = threading.Thread(target=self._CollectData) 46 self._thread.start() 47 48 def StopTracing(self): 49 self._done.set() 50 51 def PullTrace(self): 52 self._thread.join() 53 self._thread = None 54 if self._trace_data: 55 output_name = 'systrace-%s' % util.GetTraceTimestamp() 56 with open(output_name, 'w') as out: 57 out.write(self._trace_data) 58 return output_name 59 60 def IsTracingOn(self): 61 result = self._RunAdbShellCommand(['cat', _TRACING_ON_PATH]) 62 return result.strip() == '1' 63 64 def _RunAdbShellCommand(self, command): 65 # We use a separate interface to adb because the one from AndroidCommands 66 # isn't re-entrant. 67 # TODO(jbudorick) Look at providing a way to unhandroll this once the 68 # adb rewrite has fully landed. 69 device_param = (['-s', str(self._device)] if str(self._device) else []) 70 cmd = ['adb'] + device_param + ['shell'] + command 71 return cmd_helper.GetCmdOutput(cmd) 72 73 def _RunATraceCommand(self, command): 74 cmd = ['atrace', '--%s' % command] + _SYSTRACE_OPTIONS + self._categories 75 return self._RunAdbShellCommand(cmd) 76 77 def _ForceStopAtrace(self): 78 # atrace on pre-M Android devices cannot be stopped asynchronously 79 # correctly. Use synchronous mode to force stop. 80 cmd = ['atrace', '-t', '0'] 81 return self._RunAdbShellCommand(cmd) 82 83 def _CollectData(self): 84 trace_data = [] 85 self._RunATraceCommand('async_start') 86 try: 87 while not self._done.is_set(): 88 self._done.wait(_SYSTRACE_INTERVAL) 89 if not self._ring_buffer or self._done.is_set(): 90 trace_data.append( 91 self._DecodeTraceData(self._RunATraceCommand('async_dump'))) 92 finally: 93 trace_data.append( 94 self._DecodeTraceData(self._RunATraceCommand('async_stop'))) 95 if self.IsTracingOn(): 96 self._ForceStopAtrace() 97 self._trace_data = ''.join([zlib.decompress(d) for d in trace_data]) 98 99 @staticmethod 100 def _DecodeTraceData(trace_data): 101 try: 102 trace_start = trace_data.index('TRACE:') 103 except ValueError: 104 raise RuntimeError('Systrace start marker not found') 105 trace_data = trace_data[trace_start + 6:] 106 107 # Collapse CRLFs that are added by adb shell. 108 if trace_data.startswith('\r\n'): 109 trace_data = trace_data.replace('\r\n', '\n') 110 111 # Skip the initial newline. 112 return trace_data[1:] 113
