Getting the CPU Performence Of Android Device

private String ReadCPUinfo()
 {
  ProcessBuilder cmd;
  String result="";

  try{
   String[] args = {"/system/bin/cat", "/proc/cpuinfo"};
   cmd = new ProcessBuilder(args);

   Process process = cmd.start();
   InputStream in = process.getInputStream();
   byte[] re = new byte[1024];
   while(in.read(re) != -1){
    System.out.println(new String(re));
    result = result + new String(re);
   }
   in.close();
  } catch(IOException ex){
   ex.printStackTrace();
  }
  return result;
 }