AIX

I am neither a DBA nor an AIX spcialist. We are running Oralce 11G on P5, AIX5.3.
Per Oracle reports we are using 16 CPUs and 8 cores. However when I am looking at nmon report I find the cpu utilization is not load balanced.

Code:

CPU_SUMM	User%	Sys%	Wait%	Idle%
xxx001	 74.2	23.6	1.0	1.3
xxx002	 71.1	10.1	1.9	16.9
xxx003	 85.0	13.9	0.5	0.7
xxx004	 73.9	9.9	1.3	14.9
xxx005	 82.4	10.9	0.5	6.2
xxx006	 68.8	11.2	1.0	19.0
xxx007	 31.2	20.6	0.1	48.1
xxx008	 17.0	27.2	0.2	55.6
xxx009	 0.0	30.1	0.0	69.9
xxx010	 0.0	28.7	0.0	71.3
xxx011	 0.0	27.7	0.0	72.2
xxx012	 0.0	31.2	0.0	68.8
xxx013	 0.0	28.8	0.0	71.2
xxx014	 0.0	32.8	0.0	67.1
xxx015	 0.0	27.3	0.0	72.6
xxx016	 0.1	33.7	0.0	66.2

As you can see we are having some processors experiencing wait time where as some are idling. My question is simple:Are we not supposed to have some load balancing in place that would take care of the above imbalances? A more advanced question would be: What do I need to set in ORACLE/AIX to make the above a more uniformly load balanced system.

it would be a lot more helpful if you would post vmstat -Iwt instead of what you did post - but just so much - oracle is a thread based DB - and if you do not have any work for the cpus, than the cpus are not doing anything in the usersection.
The wait times you see are waiting for IO to finish rather than whatever you think it is.
AIX will ALWAYS load balance across all available cpus - primarily between the first threads of the virtual cpus first before utilizing the second thread. In addition you are doing with AIX 5.3 on p5 out of order processing - that means whatever work is available and whatever processor has the 'correct' section idling - the work will be done no matter if it would be per scheduler the next task or not.

Regards
zxmaus

If you add up column 2 and 3 and 4 and 5 it looks different already...

Code:

CPU_Nr	Busy%	Idle%
xxx001	97.8	2.3
xxx002	81.2	18.8
xxx003	98.9	1.2
xxx004	83.8	16.2
xxx005	93.3	6.7
xxx006	80	20
xxx007	51.8	48.2
xxx008	44.2	55.8
xxx009	30.1	69.9
xxx010	28.7	71.3
xxx011	27.7	72.2
xxx012	31.2	68.8
xxx013	28.8	71.2
xxx014	32.8	67.1
xxx015	27.3	72.6
xxx016	33.8	66.2

scrutinizer:
I think I did not understand your suggestion. coluld you pl explain?

There isn't much to explain. I just added up the CPU busy cycles (column 2 and 3) and the idle cycles (column 4 and 5). I thought perhaps that might give a clearer impression of the load on the various CPU's...