How to find the sessions that are using most CPUs? (Oracle)

Here is a handy script I usually use.

check_cpu.sql

prompt ====================================================
prompt == Start of check_cpu.sql
prompt ====================================================

prompt ====================================================
prompt == Check CPU notes
prompt == OS level CPU usage can be monitor by top or topas
prompt == Where you should be able to pin point the top
prompt == process ID
prompt == 
prompt ====================================================
prompt ====================================================
prompt == Show top 20 CPU usage sessions
prompt ====================================================
set lines 300
set pages 300
col machine format a20
col program format a30
col name format a30
select * from
(SELECT se.username, ss.sid,se.machine,se.program, name, se.status, ROUND (value/100) "CPU Usage Seconds", se.sql_id
FROM v$session se, v$sesstat ss, v$statname st
WHERE ss.statistic# = st.statistic#
    AND name LIKE  '%CPU used by this session%'
   AND se.sid = ss.SID 
   AND se.username IS NOT NULL
  ORDER BY value DESC)
where rownum <=20;


prompt ====================================================
prompt == Check Sql Text related to above sql_id
prompt ====================================================
SET LONG 100000 
select sql_id, SQL_TEXT from v$SQL where SQL_ID in (
select sql_id from
(SELECT se.username, ss.sid,se.machine,se.program, name, se.status, ROUND (value/100) "CPU Usage Seconds", se.sql_id
FROM v$session se, v$sesstat ss, v$statname st
WHERE ss.statistic# = st.statistic#
    AND name LIKE  '%CPU used by this session%'
   AND se.sid = ss.SID 
   AND se.username IS NOT NULL
  ORDER BY value DESC)
where rownum <=20
);

prompt ====================================================
prompt == End of check_cpu.sql
prompt ====================================================