Add cpu_stats for the browser

Implementing linux_backend for now.

BUG=263959

Review URL: https://chromiumcodereview.appspot.com/23717016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221897 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/browser.py

@@ -167,6 +167,35 @@ class Browser(object):
         self._platform_backend.GetSystemCommitCharge()
     return result
 
+  @property
+  def cpu_stats(self):
+    """Returns a dict of cpu statistics for the system.
+    { 'Browser': {
+        'CpuProcessTime': S,
+        'TotalTime': T
+      },
+      'Gpu': {
+        'CpuProcessTime': S,
+        'TotalTime': T
+      },
+      'Renderer': {
+        'CpuProcessTime': S,
+        'TotalTime': T
+      }
+    }
+    Any of the above keys may be missing on a per-platform basis.
+    """
+    result = self._GetStatsCommon(self._platform_backend.GetCpuStats)
+    del result['ProcessCount']
+
+    # We want a single time value, not the sum for all processes.
+    for process_type in result:
+      # Skip any process_types that are empty
+      if not len(result[process_type]):
+        continue
+      result[process_type].update(self._platform_backend.GetCpuTimestamp())
+    return result
+
   @property
   def io_stats(self):
     """Returns a dict of IO statistics for the browser:

tools/telemetry/telemetry/core/platform/linux_platform_backend.py

@@ -29,6 +29,14 @@ class LinuxPlatformBackend(posix_platform_backend.PosixPlatformBackend):
     meminfo_contents = self._GetFileContents('/proc/meminfo')
     return proc_util.GetSystemCommitCharge(meminfo_contents)
 
+  def GetCpuStats(self, pid=None):
+    stats = self._GetFileContents('/proc/%s/stat' % pid).split()
+    return proc_util.GetCpuStats(stats)
+
+  def GetCpuTimestamp(self):
+    timer_list = self._GetFileContents('/proc/timer_list')
+    return proc_util.GetTimestampJiffies(timer_list)
+
   def GetMemoryStats(self, pid):
     status = self._GetFileContents('/proc/%s/status' % pid)
     stats = self._GetFileContents('/proc/%s/stat' % pid).split()

tools/telemetry/telemetry/core/platform/platform_backend.py

@@ -31,6 +31,12 @@ class PlatformBackend(object):
   def GetSystemCommitCharge(self):
     raise NotImplementedError()
 
+  def GetCpuStats(self, pid):  # pylint: disable=W0613
+    return {}
+
+  def GetCpuTimestamp(self):  # pylint: disable=W0613
+    return {}
+
   def GetMemoryStats(self, pid):  # pylint: disable=W0613
     return {}
 

tools/telemetry/telemetry/core/platform/proc_util.py

@@ -22,6 +22,18 @@ def _GetProcFileDict(contents):
   return retval
 
 
+def _GetProcJiffies(timer_list):
+  """Parse '/proc/timer_list' output and returns the first jiffies attribute.
+
+  Multi-CPU machines will have multiple 'jiffies:' lines, all of which will be
+  essentially the same.  Return the first one."""
+  for line in timer_list.splitlines():
+    if line.startswith('jiffies:'):
+      _, value = line.split(':')
+      return value
+  raise Exception('Unable to find jiffies from /proc/timer_list')
+
+
 def GetSystemCommitCharge(meminfo_contents):
   meminfo = _GetProcFileDict(meminfo_contents)
   return (_ConvertKbToByte(meminfo['MemTotal'])
@@ -30,6 +42,25 @@ def GetSystemCommitCharge(meminfo_contents):
           - _ConvertKbToByte(meminfo['Cached']))
 
 
+def GetCpuStats(stats, add_children=False):
+  utime = float(stats[13])
+  stime = float(stats[14])
+  cutime = float(stats[15])
+  cstime = float(stats[16])
+
+  cpu_process_jiffies = utime + stime
+  if add_children:
+    cpu_process_jiffies += cutime + cstime
+
+  return {'CpuProcessTime': cpu_process_jiffies}
+
+
+def GetTimestampJiffies(timer_list):
+  """Return timestamp of system in jiffies."""
+  total_jiffies = float(_GetProcJiffies(timer_list))
+  return {'TotalTime': total_jiffies}
+
+
 def GetMemoryStats(status_contents, stats):
   status = _GetProcFileDict(status_contents)
   if not status or not stats or 'Z' in status['State']: