RE: Better CPU's Same Workload - CPU Utilization Remains the Same...

  • From: "Crisler, Jon" <Jon.Crisler@xxxxxxx>
  • To: <oracledbawannabe@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 16 Jul 2010 15:56:03 -0400

You should add up your total cpu's on the old 3 node cluster, and
compare total cpu power (check on to the new system.  It might
be that your total CPU power did not increase, or only increased

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Oracle Dba Wannabe
Sent: Friday, July 16, 2010 2:12 PM
To: oracledbawannabe@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: Better CPU's Same Workload - CPU Utilization Remains the

In addition to the logical io, now that I think about, we are probably
doing more sorts per node on 2 nodes compared to 3, another reason why
utilization may not have dropped. But is this and the additional io
enough to contribute to similar cpu utilization levels. Is it possible
to measure how much more cpu is working on additional logical io's?

On Fri Jul 16th, 2010 1:51 PM EDT Oracle Dba Wannabe wrote:

>Hi All,
>We recently had a change in hardware, where servers that were about 4-5
>old (SUN) were replaced with new ones (HP) - processors with better
>Generally on these old boxes (3 Node RAC). CPU utilization was
at about 
>85-90%. Now on these new servers (2 Node RAC, the workload
remains the 
>same based on  AWR transactions per second, user calls, etc.
>However I notice with the new hardware, that the same SQL now spends
less CPU 
>time for example if a particular SQL took around .4 seconds it now
takes .2 - 
>this difference is seen through pretty much all SQL statements. The
trouble is 
>though, that the CPU utilization remains the same too on these new
servers. Is 
>it correct to think that with SQL queries using less cpu time that
there would 
>be more idle time than before and hence less utilization?
>Oh as, I wrote this I just realized, since we've gone from 3 nodes to 2
nodes - 
>each box does more logical i/o than it used to - so perhaps this may
explain why 
>utilization has not dropped?
>On a side note, this question isn't about what the best utilization is,
or that 
>I'd like to drop my utilization - Just trying to understand what's
going on so I 
>can explain to management why their new hardware is showing the levels
>utilization that it is.




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