Add a little utility to capture cpu graphs.

R=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31219004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7930 4adac7df-926f-26a2-2b94-8c16560cd09d

tools/cpu/OWNERS

@@ -0,0 +1 @@
+tommi@webrtc.org

tools/cpu/README

@@ -0,0 +1,12 @@
+This directory contains a little utility for doing CPU measurements.
+It requires a Python package, psutil, to be installed.
+See: https://pypi.python.org/pypi/psutil
+
+On mac you can install this package like so:
+sudo ARCHFLAGS='-Wno-error=unused-command-line-argument-hard-error-in-future' easy_install psutil
+
+On Windows:
+- TBD (see link above)
+
+On Linux:
+- TBD (see link above)

tools/cpu/cpu_mon.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+#
+# Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+
+import argparse
+import psutil
+import sys
+
+import numpy
+from matplotlib import pyplot
+
+
+class CpuSnapshot(object):
+  def __init__(self, label):
+    self.label = label
+    self.samples = []
+
+  def Capture(self, sample_count):
+    print ('Capturing %d CPU samples for %s...' %
+           ((sample_count - len(self.samples)), self.label))
+    while len(self.samples) < sample_count:
+      self.samples.append(psutil.cpu_percent(1.0, False))
+
+  def Text(self):
+    return ('%s: avg=%s, median=%s, min=%s, max=%s' %
+            (self.label, numpy.average(self.samples),
+             numpy.median(self.samples),
+             numpy.min(self.samples), numpy.max(self.samples)))
+
+  def Max(self):
+    return numpy.max(self.samples)
+
+
+def GrabCpuSamples(sample_count):
+  print 'Label for snapshot (enter to quit): '
+  label = raw_input().strip()
+  if len(label) == 0:
+    return None
+
+  snapshot = CpuSnapshot(label)
+  snapshot.Capture(sample_count)
+
+  return snapshot
+
+
+def main():
+  print 'How many seconds to capture per snapshot (enter for 60)?'
+  sample_count = raw_input().strip()
+  if len(sample_count) > 0 and int(sample_count) > 0:
+    sample_count = int(sample_count)
+  else:
+    print 'Defaulting to 60 samples.'
+    sample_count = 60
+
+  snapshots = []
+  while True:
+    snapshot = GrabCpuSamples(sample_count)
+    if snapshot == None:
+      break
+    snapshots.append(snapshot)
+
+  if len(snapshots) == 0:
+    print 'no samples captured'
+    return -1
+
+  pyplot.title('CPU usage')
+
+  for s in snapshots:
+    pyplot.plot(s.samples, label=s.Text(), linewidth=2)
+
+  pyplot.legend()
+
+  pyplot.show()
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main())