title: Profile cpu and memory usage during py.test execution
body: <p>I am facing the following project. I want to create pictures showing the cpu and memory level during the execution of a set of performance test suites. I would appreciate any suggestion.</p>
  
  <p>Currently the only approach I am considering is to use the command top or the python module <a href="https://pypi.python.org/pypi/psutil" rel="nofollow">psutil</a> and execute them in parallel to the tests. However I was wondering whether there exists already a better approach, may be a py.test plugin.</p>
  
  <p>A nice to have would be be able to compare those parameters from one execution to another.</p>
  
  <p>The tests are executed Under Linux (Ubuntu).</p>