How to find out CPU savings

amolph · New User Joined: 28 Dec 2007 Posts: 4 Location: pune

I have set of jobs which I run through CA7. The set of jobs take 2.5 hours to complete. I have modified the set now and will take only 1 hour to complete. I can easily find out time saving ,however how can I understand ,how much CPU I have saved .

dick scherrer · Posted: Wed Dec 31, 2008 10:47 am

Hello,

Many organizations run monthly reports showing resource usage by job. Often there is a file created of job related data that developers and others may use to generate such reports. You might ask if these exist and review them.

If there is nothing already in place, the info you want will be available in the SMF data.

In either case, you would talk with your scheduling or system support people to find out what is available.

amolph · New User Joined: 28 Dec 2007 Posts: 4 Location: pune

Thanks Dick.
Will check then and get those reports.

dick scherrer · Posted: Wed Dec 31, 2008 10:59 am

You're welcome - good luck

d

expat · Posted: Wed Dec 31, 2008 12:29 pm

Although it is not clear exactly what you did to modify the application, there are a couple of points to think about.

If you have only amended the process order then there will be zero savings.

If you have amended the code or even execution JCL, then there is the possibility that you may have increased CPU consumption.

Also consider what else is running at the same time as your jobs. This workload can affect the elapsed times of your application without any effect on CPU consumption.

amolph · New User Joined: 28 Dec 2007 Posts: 4 Location: pune

Thanks.
I have reduced the work load e.g. taking backup of 10 DBs insted taking backup of 20 in previous case.I think this should save CPU.

expat · Posted: Wed Dec 31, 2008 1:11 pm

But does it compromise data integrity or rerun capability by removing the extra backups ?

Robert Sample · Posted: Wed Dec 31, 2008 5:25 pm

Elapsed time has only a tenuous relationship to CPU time -- a point which cannot be made enough since a lot of people don't understand it. Elapsed time is more affected by system load, WLM definitions, I/O contention, paging, and so forth. Even a simple change like adding buffers to DD statements can cut elapsed time by 80%.

If you want to find CPU savings, you can generally find a summary of the job in the listing, which typically gives TCB and SRB time for the entire job. Add these values and you'll have the CPU time used for the job.