[Telemetry] Add memory and IO stats to page cycler

tools/telemetry/telemetry/core/chrome/cros_platform_backend.py

Index: tools/telemetry/telemetry/core/chrome/cros_platform_backend.py
diff --git a/tools/telemetry/telemetry/core/chrome/cros_platform_backend.py b/tools/telemetry/telemetry/core/chrome/cros_platform_backend.py
new file mode 100644
index 0000000000000000000000000000000000000000..03515530ddce859b0111f3f99cd633ecc33cef22
--- /dev/null
+++ b/tools/telemetry/telemetry/core/chrome/cros_platform_backend.py
@@ -0,0 +1,74 @@
+# Copyright (c) 2013 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.
+
+try:
+  import resource  # pylint: disable=F0401
+except ImportError:
+  resource = None  # Not available on all platforms
+
+from telemetry.core.chrome import platform_backend
+
+
+class CrosPlatformBackend(platform_backend.PlatformBackend):
+  def __init__(self, cri):
+    super(CrosPlatformBackend, self).__init__()
+    self._cri = cri
+
+  def _GetFileContents(self, filename):
+    try:
+      return self._cri.GetCmdOutput(['cat', filename])
+    except AssertionError:
+      return ''
+
+  def _GetProcFileDict(self, filename):
+    retval = {}
+    for line in self._GetFileContents(filename).splitlines():
+      line = line.strip()
+      key_val = line.split(':')
+      assert len(key_val) == 2
+      try:
+        retval[key_val[0]] = int(key_val[1].replace('kB', ''))
+      except Exception:
+        pass
+    return retval
+
+  # pylint: disable=W0613
+  def StartRawDisplayFrameRateMeasurement(self, trace_tag):
+    raise NotImplementedError()
+
+  def StopRawDisplayFrameRateMeasurement(self):
+    raise NotImplementedError()
+
+  def IsThermallyThrottled(self):
+    raise NotImplementedError()
+
+  def HasBeenThermallyThrottled(self):
+    raise NotImplementedError()
+
+  def GetSystemCommitCharge(self):
+    meminfo = self._GetProcFileDict('/proc/meminfo')
+    return (meminfo['MemTotal'] - meminfo['MemFree'] - meminfo['Buffers'] -
+            meminfo['Cached'])
+
+  def GetMemoryStats(self, pid):
+    status = self._GetProcFileDict('/proc/%s/status' % pid)
+    stats = self._GetFileContents('/proc/%s/stat' % pid).split(' ')
+    if not status or not stats:
+      return {}
+    return {'VM': int(stats[22]),
+            'VMPeak': status['VmPeak'] * 1024,
+            'WorkingSetSize': int(stats[23]) * resource.getpagesize(),
+            'WorkingSetSizePeak': status['VmHWM'] * 1024}
+
+  def GetChildPids(self, pid):
+    """Retunds a list of child pids of |pid|."""
+    child_pids = []
+    pid_ppid_list = self._cri.GetCmdOutput(
+        ['ps', '-e', '-o', 'pid=', '-o', 'ppid='])
+    for pid_ppid in pid_ppid_list.splitlines():
+      curr_pid, curr_ppid = pid_ppid.split()
+      if int(curr_ppid) == pid:
+        child_pids.append(int(curr_pid))
+        child_pids.extend(self.GetChildPids(int(curr_pid)))
+    return child_pids