正则表达式性能问题

           Stopwatch w = new Stopwatch();
           w.Start();
           Regex r = new Regex(@".*", RegexOptions.Compiled );
             Match m = r.Match("aaa");
             if (m.Success)
             {
                 w.Stop();
                 Response.Write(w.Elapsed.TotalSeconds.ToString("0.0000000"));
              
             }