As has been stated before, Capacity and Performance is not a casual thing that you can do over lunch. That being said, you can look at a few things. 100% is not a bad thing, modern mainframes are designed to run at 100%. The question is whether things are being delayed. If you have access to RMF data, you can look at the PI (performance index) of individual service classes over a certain interval. This is much easier if you have a tool other than RMF, but you have to use what you have. If the PIs are greater than 1.0, you're being delayed and that's where you're problem is residing.
Not sure how Workload Manager is being used or configured at your shop. Check the coefficients value. Oddly enough, a fair number of shops take the default values (which are wrong) instead of the recommended (which should be the default, but they're not). Not sure what type of box you're using (i.e. z9, z10, etc). Is there a defined capacity set, and is that capacity set higher or lower than the initialization values? This can wreck all sorts of havoc when the system gets busy. Are your catalogs loaded into memory? Kind of difficult to determine where your problem might lie, because it literally could be anything. Adding processors may or may not help, and could actually make things worse. Depending on your box type, increasing the number of processors without increasing the number of MSUs (and thus changing your classification) will lower the number of MIPS each processor will execute per second. If you're running DB2 or think a zIIP might help, you can set PROJECTCPU to YES (in IEAOPT00) and find out. You can also check the values for the percentage of I/O interruptions to be processed through the test pending interrupt. It should be 10,30. Also ERV - then number of CPU service units and address space can absorb when it's possibly causing enqueue contentions. The default is 500, which might be too low for your shop. Good luck. Anne R. Adams DTI, Systems Engineering (302) 298 - 3196 -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of RCG Sent: Wednesday, November 07, 2012 9:30 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: CPU Utilization Dear Group, In one of the shop that I work, I have CPU constraint where the utilization is @ 100% most of the times and that is impacting much of the services which is obvious, I am not a Performance / Capacity expert nor thats my day to day work, Though I am still looking for the ways where we can better the utilization and atleast reduce the impact, additional CPU would definitely resolve that, But that is not something the customer is interested with, I am doing some reading to help tune the performance, Also trying to figure out any batch loads that are of not high priority to run over a non-peak hours which might help a bit to it, Any expert advice on the other ways that i can consider to help would be highly appreciated, Thanks much in advance ! Regards, ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
