code: def get_passenger_cpu_usage(self, dict_stats):
          
          try:
              proc1 = subprocess.Popen(
                  ["top", "-b", "-n", "2"],
                  stdout=subprocess.PIPE)
              (std_out, std_err) = proc1.communicate()
          except OSError:
              return (-1)
  
          re_lspaces = re.compile("^\s*")
          re_digit = re.compile("^\d")
          overall_cpu = 0
          for raw_line in std_out.splitlines():
              line = re_lspaces.sub("", raw_line)
              if not re_digit.match(line):
                  continue
  
              line_splitted = line.split()
              if line_splitted[0] in dict_stats["apache_procs"]:
                  overall_cpu += float(line_splitted[8])
              elif line_splitted[0] in dict_stats["nginx_procs"]:
                  overall_cpu += float(line_splitted[8])
              elif line_splitted[0] in dict_stats["passenger_procs"]:
                  overall_cpu += float(line_splitted[8])
  
          return overall_cpu
docs: Execute % top; and return STDOUT.