Comments on: Limit/restrict CPU% for a job in AS400

By: philpl1jb

philpl1jb — Thu, 04 Mar 2010 02:53:28 +0000

As pointed out in all responses. The AS/400 operating system optimizes the active job load, this is generally considered a good thing. Changing the run priority and inserting delays will favor other jobs, but when it’s not delayed your job will still get the unused resources. But we could .. help you make a “fake” version of WRKACTJOB that shows 2%.
Phil

By: tomliotta

tomliotta — Wed, 03 Mar 2010 21:16:37 +0000

…when my job is running, people (the other users on the system) see the CPU% and are scary to submit/release their jobs.

IMO, no one who doesn’t understand what “CPU %” means should even see the “CPU %” figure for that exact reason. You cannot satisfy people who don’t know the meaning of what they’re saying.

As already asked and not yet answered — What is the time interval for a percentage? And how are you figuring the 2% value?

Until those questions are answered by you, there is no valid answer to your question because there isn’t enough information about it yet.

Tom

By: vvnmurty

vvnmurty — Wed, 03 Mar 2010 15:10:17 +0000

I am in a way not satisfied with any of the responses got so far on this task. My main purpose is; when my job is running, people (the other users on the system) see the CPU% and are scary to submit/release their jobs. Even for a nano second, my job should not show above a certain percentage of CPU usage. I reiterate even if the system or the processor (as the other friends say), is absolutely free, my job should not show more than a 5 or 10% CPU usage.

Even if I put a delay job (as suggested by one of the members), I am not getting the required result. My file is an old file of 10 year history data with 80 GB (you are right, it is 80 GB), even if I process 10000 records in it, system takes a lot time to set my pointer to the required records.

Can anybody throw some light on this. I belive if there are members from IBM they can resolve this fast.

By: vatchy

vatchy — Fri, 19 Feb 2010 15:42:10 +0000

Try using the CL command DlyJob. Process some number of records – experiment with this – and then delay the job for 2-3 seconds. A little testing should give you the results that you need. You can use QCmdExc to execute the DlyJob command from an RPG program.

By: mcl

mcl — Thu, 18 Feb 2010 21:22:52 +0000

If the system is not doing anything else, why do you care if your job gets all the CPU? The O/S is doing what it is supposed to be doing. Don’t try to fix it!

You can throttle a job to use less CPU, but that really only becomes apparent when the system is busy.

Regards
Mike

By: tomliotta

tomliotta — Wed, 17 Feb 2010 21:00:06 +0000

I have to run the job with say a maximum of 2% CPU.

What is the time interval for a percentage? That’s important because your job will use 100% of the CPU during the times that it is actually running. Control over, say, a 30-minute interval is easier than over a 1-minute interval.

Whether some system function manages your CPU usage or some monitor of your own does it, it will take more CPU to execute the controlling process if it must track smaller intervals. For a 2% maximum threshold, you might start spending resources to keep your job under control that start to approach the resources of the job itself.

So, how are figuring the 2% value?

Tom