Expert: Concise Systems/Laird Scranton - 3/14/2001

Question
Is the batch environment in the AS/400 supposed to run at 99 to ++++ % CPU usage at times? Why/Why not?  

Answer
The CPU usage percentage on the Work With System Status (WRKSYSSTS) screen indicates what percentage of the time the system was in use, so anytime a long continuous batch job is running, the system will be in use nearly 100% of the time it runs. That doesn't mean the system is overburdened - just that it was in use during that time. Better indicators of how well your system is performing are the database-fault and non-database fault rates for each storage pool.  The higher these numbers are, the less efficiently the system is running. Numbers from .1 through 2.00 in any given pool indicate a well-tuned/well-balanced system. The numbers may jump up for a short time and then fall back down - that's normal and perfectly OK.  For best results, reset the statistics on the screen every 10 minutes or so - otherwise, over a long time period, the highs and lows will simply average out and not give you a very good picture of how your system is performing.

Performance tuning is an easy way to improve your system response time for not much work or cost.  The right technical person can tune your system in under a day, and you will probably see a noticable difference in throughput.

The key question to ask yourself about system performance is whether your users are happy with their response time. If they are, you don't have a problem.  Otherwise, it makes sense to take steps to improve it.

Laird Scranton
Concise Systems