In between I posted more than 500 blog entries.
... but now to my topic for today:
When I am looking into z/VSE performance issues, in most cases I am asking customers to install the z/VSE CPU Monitoring Tool (CPUMON).
If you run CPUMON, it will provide the CPU utilization, MSUs, non-parallel share, multiprocessor exploitation and much more for the monitored time period.
It can not replace a performance monitor, however. Performance monitors are available from z/VSE vendors.
Back to CPUMON - just let the tool run for a day or more and use e.g. minute intervals.
If you load the monitored data into a spreadsheet, you can get a line chart with e.g. the CPU utilization, where you see the CPU peaks of your workload.
The additional overhead of the tool is very low. You may not even notice it.
You may use CPUMON also from time to time to get a better understanding of your workload behavior or growth. If you plan to migrate to a new processor, CPUMON may also help to size the new system. But I also recommend to monitor your workload before you migrate to a new processor or z/VSE release and save the data for later comparison with the new environment.
Best would be to monitor days that have comparable workloads. So you can see how the workload behaves on the new system or release.
I also worked with customers - and CPUMON - to improve the batch window. That is if you analyze workload peaks and understand the jobs, that run during that time (additional tools or job accounting data are required to see job start and end times) you may start jobs at less utilized times and so avoid CPU bottlenecks.
Are you interested in the tool ? If so, you may download it from our web page - here.
The zip file also contains a good description how to use the tool.
... and finally an example of a workload.
blue = % CPU utilization, red = % non-parallel utilization, green = max. CPUs, that can be exploited