src/Pure/Admin/isabelle_cronjob.scala

     def log_end(end_date: Date, err: Option[String])
     {
       val elapsed_time = end_date.time - start_date.time
       val msg =
         (if (err.isEmpty) "finished" else "ERROR " + err.get) +
-        (if (elapsed_time.seconds < 3.0) "" else ", elapsed time " + elapsed_time.message_hms)
+        (if (elapsed_time.seconds < 3.0) "" else " (" + elapsed_time.message_hms + " elapsed time)")
       log(end_date, msg)
     }
 
     val log_dir: Path = main_dir + Build_Log.log_subdir(start_date)