Engineering – Part 8 – Remote Access Detection

The fact we’re up to “Part 8” illustrates there’s a lot to talk about once you take performance analysis down to the individual logical / physical processor level. Many people have talked about the need to avoid LPARs crossing processor drawer boundaries. There are good reasons for this – because access to cache or memoryContinue reading “Engineering – Part 8 – Remote Access Detection”

Engineering – Part 7 – RMF Processor Home Address Fields

I was recently asked where I was getting the home addresses for logical processors from in RMF SMF 70. I will agree the fields I use are not that easy to interpret – so here’s my go at making them more accessible. Along the way I’ll also talk about SMF 74 Subtype 4 Coupling FacilityContinue reading “Engineering – Part 7 – RMF Processor Home Address Fields”

Relating Parked Time To Cores

In Drawers And More I mentioned Parking with the words One day I’ll be able to colour VL’s according to whether they are parked or not – or rather fractions of the interval they’re parked. That’s a not very difficult fix for the python code. Well, that proved as simple as I thought. So, alongContinue reading “Relating Parked Time To Cores”

Drawers, Of Course

This post is about processor drawers and how the topic might influence your LPAR design. Introduction Once upon a time drawers and books were very simple. If you wanted a certain number of processors – whether GCP, zIIP, zAAP, IFL, or ICF – that determined the number of drawers you had. (I’m still hearing peopleContinue reading “Drawers, Of Course”

Mainframe Performance Topics Podcast Episode 34 “Homeward Bound”

We started planning this one quite a while ago. Thankfully our topics tend to be evergreen – in that they’re still topical for quite a while. In that vein I know we are gaining new listeners and they aren’t all starting with the latest episode. Anyway, our schedules have been their usual hectic selves –Continue reading “Mainframe Performance Topics Podcast Episode 34 “Homeward Bound””

Bursty Batch – Small Reprise

In Bursty Batch I talked about how some customers have large amounts of batch work coming in all at once, and how a new WLM function in z/OS 3.1 might be handy in catering for it. And it subsequently occurred to me there is a cheap-to-collect and therefore almost universal method of assessing how burstyContinue reading “Bursty Batch – Small Reprise”

z16 ICA-SR Structure Service Times

It was recently brought to my attention that CFLEVEL 25, made available with IBM z16, improved ICA-SR links. (I don’t know why I didn’t spot this before – but it’s documented in several places, including IBM Db2 13 for z/OS Performance Topics, an interesting Redbook. (I actually read this from cover to cover during aContinue reading “z16 ICA-SR Structure Service Times”