[polymer] Merge of master into polymer10-migration

telemetry/telemetry/internal/platform/tracing_agent/cpu_tracing_agent.py

+# 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.
+
+import json
+import os
+try:
+  import psutil
+except ImportError:
+  psutil = None
+import subprocess
+from threading import Timer
+
+from py_trace_event import trace_time
+from telemetry.internal.platform import tracing_agent
+from telemetry.timeline import trace_data
+
+DEFAULT_MIN_PCPU = 0.1
+
+class ProcessCollector(object):
+
+  def __init__(self, min_pcpu):
+    self._min_pcpu = min_pcpu
+
+  def GetProcesses(self):
+    return NotImplemented
+
+class UnixProcessCollector(ProcessCollector):
+
+  _SHELL_COMMAND = NotImplemented
+  _START_LINE_NUMBER = 1
+  _TOKEN_COUNT = 4
+  _TOKEN_MAP = {
+    'pCpu': 2,
+    'pid': 0,
+    'pMem': 3,
+    'command': 1
+  }
+
+  def __init__(self, min_pcpu, binary_output=False):
+    super(UnixProcessCollector, self).__init__(min_pcpu)
+    self._binary_output = binary_output
+
+  def _ParseLine(self, line):
+    """Parses a line from top output
+
+    Args:
+      line(str): a line from top output that contains the information about a
+                 process.
+
+    Returns:
+      An dictionary with useful information about the process.
+    """
+    token_list = line.strip().split()
+    if len(token_list) != self._TOKEN_COUNT:
+      return None
+    return {attribute_name: token_list[index]
+            for attribute_name, index in self._TOKEN_MAP.items()}
+
+  def GetProcesses(self):
+    """Fetches the top processes returned by top command.
+
+    Returns:
+      A list of dictionaries, each representing one of the top processes.
+    """
+    if self._binary_output:
+      processes = subprocess.check_output(self._SHELL_COMMAND).decode(
+        'ascii').split('\n')
+    else:
+      processes = subprocess.check_output(self._SHELL_COMMAND).split('\n')
+    process_lines = processes[self._START_LINE_NUMBER:]
+    top_processes = []
+    for process_line in process_lines:
+      process = self._ParseLine(process_line)
+      if (not process) or (float(process['pCpu']) < self._min_pcpu):
+        continue
+      top_processes.append(process)
+    return top_processes
+
+
+class WindowsProcessCollector(ProcessCollector):
+  """Class for collecting information about processes on Windows.
+
+  Windows does not have a fast and simple command to list processes, so psutil
+  package is used instead."""
+
+  def __init__(self, min_pcpu):
+    super(WindowsProcessCollector, self).__init__(min_pcpu)
+
+  def GetProcesses(self):
+    data = []
+    for p in psutil.process_iter():
+      try:
+        cpu_percent = p.get_cpu_percent(interval=0)
+        if cpu_percent >= self._min_pcpu:
+          data.append({
+            'pCpu': cpu_percent,
+            'pMem': p.get_memory_percent(),
+            'command': p.name,
+            'pid': p.pid
+          })
+      except psutil.Error:
+        pass
+    data = sorted(data, key=lambda d: d['pCpu'],
+                  reverse=True)
+    return data
+
+
+class LinuxProcessCollector(UnixProcessCollector):
+  """Class for collecting information about processes on Linux.
+
+  Example of Linux command output: '31887 com.app.Webkit 3.4 8.0'"""
+
+  _SHELL_COMMAND = ["ps", "axo", "pid,cmd,pcpu,pmem", "--sort=-pcpu"]
+
+
+  def __init__(self, min_pcpu):
+    super(LinuxProcessCollector, self).__init__(min_pcpu)
+
+
+class MacProcessCollector(UnixProcessCollector):
+  """Class for collecting information about processes on Mac.
+
+  Example of Mac command output:
+  '31887 com.app.Webkit 3.4 8.0'"""
+
+  _SHELL_COMMAND = ['ps', '-arcwwwxo', 'pid command %cpu %mem']
+
+  def __init__(self, min_pcpu):
+    super(MacProcessCollector, self).__init__(min_pcpu, binary_output=True)
+
+
+class CpuTracingAgent(tracing_agent.TracingAgent):
+
+  SNAPSHOT_FREQUENCY = 1.0
+
+  def __init__(self, platform_backend, min_pcpu=DEFAULT_MIN_PCPU):
+    super(CpuTracingAgent, self).__init__(platform_backend)
+    self._snapshot_ongoing = False
+    self._snapshots = []
+    os_name = platform_backend.GetOSName()
+    if  os_name == 'win':
+      self._collector = WindowsProcessCollector(min_pcpu)
+    elif os_name == 'mac':
+      self._collector = MacProcessCollector(min_pcpu)
+    else:
+      self._collector = LinuxProcessCollector(min_pcpu)
+
+  @classmethod
+  def IsSupported(cls, platform_backend):
+    os_name = platform_backend.GetOSName()
+    return (os_name in ['mac', 'linux']) or (os_name == 'win' and psutil)
+
+  def StartAgentTracing(self, config, timeout):
+    assert not self._snapshot_ongoing, (
+           'Agent is already taking snapshots when tracing is started.')
+    if not config.enable_cpu_trace:
+      return False
+    self._snapshot_ongoing = True
+    self._KeepTakingSnapshots()
+    return True
+
+  def _KeepTakingSnapshots(self):
+    """Take CPU snapshots every SNAPSHOT_FREQUENCY seconds."""
+    if not self._snapshot_ongoing:
+      return
+    # Assume CpuTracingAgent shares the same clock domain as telemetry
+    self._snapshots.append((self._collector.GetProcesses(), trace_time.Now()))
+    Timer(self.SNAPSHOT_FREQUENCY, self._KeepTakingSnapshots).start()
+
+  def StopAgentTracing(self):
+    assert self._snapshot_ongoing, (
+           'Agent is not taking snapshots when tracing is stopped.')
+    self._snapshot_ongoing = False
+
+  def CollectAgentTraceData(self, trace_data_builder, timeout=None):
+    assert not self._snapshot_ongoing, (
+           'Agent is still taking snapshots when data is collected.')
+    self._snapshot_ongoing = False
+    data = json.dumps(self._FormatSnapshotsData())
+    trace_data_builder.SetTraceFor(trace_data.CPU_TRACE_DATA, data)
+
+  def _FormatSnapshotsData(self):
+    """Format raw data into Object Event specified in Trace Format document."""
+    pid = os.getpid()
+    return [{
+      'name': 'CPUSnapshots',
+      'ph': 'O',
+      'id': '0x1000',
+      'local': True,
+      'ts': timestamp,
+      'pid': pid,
+      'tid':None,
+      'args': {
+        'processes': snapshot
+      }
+    } for snapshot, timestamp in self._snapshots]