Well you can trace the awrrpt run...

I suspect (but don't know for sure) that AWR uses DBA_HIST_SYS_TIME_MODEL
for its CPU info... V$SYS_TIME_MODEL CPU values can differ from V$SYSSTAT
ones...

SQL> select
2   a.value/1000000 time_model_seconds,
3   b.value/10000  sysstat_seconds,
4   a.value/1000000 - b.value/10000 missing_seconds
5 from
6   v$sys_time_model a,
7   v$sysstat b
8 where
9   a.stat_name = 'DB CPU'
10 and b.name = 'CPU used by this session'
11 /

TIME_MODEL_SECONDS SYSSTAT_SECONDS MISSING_SECONDS
------------------ --------------- ---------------
    126.997282       4.6276    122.369682


--
Regards,
Tanel Poder
http://blog.tanelpoder.com


> -----Original Message-----
> From: oracle-l-bounce@(protected)
> [mailto:oracle-l-bounce@(protected)
> Fernando Cerri
> Sent: Thursday, November 01, 2007 23:20
> To: oracle-l@(protected)
> Subject: CPU Time calculation in AWR Reports
>
> Hello, list.
>
> At Statspack age, 'CPU Time' value in section 'Top 5 Timed
> Events' was calculated as the difference of 'CPU used by this
> session' values between two snapshots:
>
>                select 'CPU' , (e.value-b.value)/100 time
>                 from stats$sysstat b, stats$sysstat e
>                 where e.snap_id      = :v_eid
>                  and b.snap_id      = :v_bid
>                  and e.name        = 'CPU used
> by this session'
>                  and b.name        = 'CPU used
> by this session';
>
>

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