1 files changed, 96 insertions, 0 deletions
diff --git a/catapult/systrace/systrace/tracing_agents/android_cgroup_agent.py b/catapult/systrace/systrace/tracing_agents/android_cgroup_agent.py
new file mode 100644
index 00000000..75e0872d
--- /dev/null
+++ b/catapult/systrace/systrace/tracing_agents/android_cgroup_agent.py
@@ -0,0 +1,96 @@
+# Copyright 2020 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.
+
+# Tracing agent that captures cgroup information from /dev/cpuset on
+# an Android device.
+
+import stat
+import py_utils
+
+from devil.android import device_utils
+from systrace import tracing_agents
+from systrace import trace_result
+
+# identify this as trace of cgroup state
+TRACE_HEADER = 'CGROUP DUMP\n'
+
+def add_options(parser): # pylint: disable=unused-argument
+  return None
+
+def try_create_agent(config):
+  if config.target != 'android':
+    return None
+  if not config.atrace_categories:
+    return None
+  # 'sched' contains cgroup events
+  if 'sched' not in config.atrace_categories:
+    return None
+  if config.from_file is not None:
+    return None
+  return AndroidCgroupAgent()
+
+def get_config(options):
+  return options
+
+def parse_proc_cgroups(cgroups, subsys):
+  for line in cgroups.split('\n'):
+    if line.startswith(subsys):
+      return line.split()[1]
+  return '-1'
+
+class AndroidCgroupAgent(tracing_agents.TracingAgent):
+  def __init__(self):
+    super(AndroidCgroupAgent, self).__init__()
+    self._config = None
+    self._device_utils = None
+    self._trace_data = ""
+
+  def __repr__(self):
+    return 'cgroup_data'
+
+  @py_utils.Timeout(tracing_agents.START_STOP_TIMEOUT)
+  def StartAgentTracing(self, config, timeout=None):
+    self._config = config
+    self._device_utils = device_utils.DeviceUtils(
+        self._config.device_serial_number)
+
+    if not self._device_utils.HasRoot():
+      return False
+
+    self._trace_data += self._get_cgroup_info()
+    return True
+
+  @py_utils.Timeout(tracing_agents.START_STOP_TIMEOUT)
+  def StopAgentTracing(self, timeout=None):
+    return True
+
+  @py_utils.Timeout(tracing_agents.GET_RESULTS_TIMEOUT)
+  def GetResults(self, timeout=None):
+    result = TRACE_HEADER + self._trace_data
+    return trace_result.TraceResult('cgroupDump', result)
+
+  def SupportsExplicitClockSync(self):
+    return False
+
+  def RecordClockSyncMarker(self, sync_id, did_record_sync_marker_callback):
+    pass
+
+  def _get_cgroup_info(self):
+    data = []
+    CGROUP_SUBSYS = 'cpuset'
+    CGROUP_ROOT = '/dev/cpuset/'
+
+    cgroups = self._device_utils.ReadFile('/proc/cgroups')
+    header = '# cgroup task attachment\n'
+
+    root_id = parse_proc_cgroups(cgroups, CGROUP_SUBSYS)
+
+    for cgrp in self._device_utils.StatDirectory(CGROUP_ROOT):
+      if not stat.S_ISDIR(cgrp['st_mode']):
+        continue
+      tasks_file = CGROUP_ROOT + cgrp['filename'] + '/tasks'
+      tasks = self._device_utils.ReadFile(tasks_file).split('\n')
+      cgrp_info = '/%s (root=%s) : ' % (cgrp['filename'], root_id)
+      data.append(cgrp_info  + ' '.join(tasks))
+    return cgroups + header + '\n'.join(data) + '\n'