Re: Account DB CPU vs OS CPU

I have do some data reasearch this weekend.

So I got these figures:

Total CPU time available for 1 hour (number of cpu * 3600): 72000 seconds Host CPU Utilization (from dba_hist_sysmetric_summary) for 1 hour average: 97.59%
Database CPU (DB CPU + RMAN cpu + background cpu time from DBA_HIST_SYS_TIME_MODEL) for 1 hour: 53419 seconds which is around 74.19% CPU usage when databases are idle (got this figure from other idle RAC nodes): 18%

So 74.19 + 18 we get 92.19%, quite close to 97.59%. Looks pretty good how Oracle count CPU.

Thanks

--
LSC



On Fri, Sep 25, 2009 at 5:51 AM, Tanel Poder <tanel_at_poderc.com> wrote::



> Hi,

>

> The background processes CPU time is accounted separately from DB CPU ->

> its called "background cpu time"

>

> Tanel.

>

>

> On Fri, Sep 25, 2009 at 2:34 AM, Christo Kutrovsky <

> kutrovsky.oracle_at_gmail.com> wrote:

>

>> How did you measure CPU usage over the period of time ?

>>

>> I can't tell you for sure, but here's a few thinking points.

>> - dbwriter and other background processes - are these accounted in DB CPU

>> ?

>> - LMS processes - are these accounted in DB CPU ?

>> - listener, clusterware, process initialization - those are not accounted

>> for

>>

>>

>> --

>> Christo Kutrovsky

>> Senior Consultant

>> The Pythian Group

>>

>


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