Martin talks Mainframe, sometimes Performance, and whatever other topics take his fancy.
Wouldn’t you like to know where in the machine an LPAR’s memory is? Perhaps not but for some customers it’s more than a matter of idle curiosity. The good news is that RMF will be able to tell you: A recent APAR for z/OS 3.2 Data Gatherer OA68545 exploits information from z17 processors to provide Continue reading "Memories Are Made Of This"
Or “An Indecent Interval”? I’ve written about RMF intervals before when writing about System Recovery Boost. I suppose one lesson of this post is to not assume that all intervals are of equal length. We’ve got pretty used to assuming that a system’s RMF interval is, say, 15 minutes long. We’ve maybe got used Continue reading "Mind The Gap"
It’s possible I’ve written about this before. If so it’s been a while. What I certainly have written about in the past is the SMF 30 Usage Data Section. I will have described how it can be used to describe architectural attributes of an address space or batch job. For example: (I probably shouldn’t go Continue reading "Product CPU Usage A Sometimes Useful Metric"
It is rare to need to evacuate hardware. But being rare is not an excuse to neglect to plan for it. Obviously I ve been sensitised to the question by real customer situations though I don t intend to describe the situations in any detail; This post should prove useful enough without doing that. When I Continue reading "Prepare To Evacuate"
When assessing how well a WLM policy protects key work it’s necessary to understand how much CPU is used at each importance level. \ If there is very little work at a lower importance (higher importance number) a CPU crunch will leave work at this importance level vulnerable to CPU queuing. Let me give a Continue reading "What s Important? CICS Transaction vs Region Goals"
In Engineering Part 8 Remote Access Detection I talked about reasons why LPARs might go cross-drawer. One reason I didn’t give was about memory. (I should perhaps remind you that on modern machines a logical processor accessing Level 4 Cache or memory in another processor drawer incurs a significant performance penalty, showing up Continue reading "Remember Memory"
They were simpler times back then. “Back when?” You might ask. When PR/SM got started in the mid 1980’s a machine might have two or three LPARs. Similarly, when Parallel Sysplex got started the number of members was very small. For reference, a z17 ME1 can have up to 85 LPARs, and a Continue reading "Two Of These Are Not Like The Others"
Modern Machines, Modern Metrics In z17 Sustainability Metrics Part 0 I wrote about the new z17 Sustainability Metrics, or Power Consumption , if you prefer. This post isn t part 1 as I don t intend to go into much detail about what I ve learnt so far. I have learnt things, of course. During the Summer Continue reading "Modern Machines, Modern Metrics"
If the purpose of Version 5 was to add the ability to use Python in the context of md2pptx the purpose of version 6 is to extend md2pptx s automation capabilities still further. This time instead of Python it s AppleScript. The context is different too: With Version 5 the Python support runs the user-supplied code as Continue reading "md2pptx 6 Is Another Big Step Forward"
A while back I experimented with executing user-provided Python. It seemed a small step at the time, but I had a hunch it would turn out to be a much bigger thing. Coding it was straightforward but two things delayed releasing it: Documentation is tricky. The python-pptx API is (necessarily) not for the faint of Continue reading "md2pptx 5 Is A Big Step Forward"
I wondered a while back why I hadn t got mdpre to 1.0. It turns out there were still some things I felt it needed to have it graduate . I suppose I should explain what mdpre actually is. It s a tool for preprocessing text into Markdown, This text is almost Markdown or Markdown+ so you can Continue reading "mdpre Comes Of Age"
A long time ago I wrote blog posts about driving Unix System Services from REXX. My motivation at the time was relatively minor. Now, however, I have a stronger motivation: Python. You might or might not be aware that z/OS has modern Python support and I expect it to keep up very well as Continue reading "REXX And Python"
I’ve had a task on my to-do list for some time now to assess the state of my blog and publish some posts I knew I had drafted. Typically I write posts while in the air as there’s precious little else to do. So I’d written several some with more topicality than others. Continue reading "Well, That s Embarrassing"
I call this Part 0 because I haven t yet seen any data. However I think it useful to start here, rather than waiting for customer data to appear for two reasons: Sharing what data is available is useful. Showing how folklore is built is instructive and useful. As you might expect, I ve been down Continue reading "z17 Sustainability Metrics Part 0"
We were especially keen to get a podcast episode out on the day z17 was announced, having both worked on the launch project in various capacities. So, for once there was a deadline which we actually made. It was a pleasure to record this, with almost every piece of it related to z17. So Continue reading "Mainframe Performance Topics Podcast Episode 36 Telum Like It Is "
As usual it s taken us longer than we would like. The usual problem of finding planning and recording slots we can both make applies. But I think the episode turned out well. It was certainly fun to make. So here are the show notes. Episode 35 In Search Of EXCELence? long show notes This episode Continue reading "Mainframe Performance Topics Podcast Episode 35 In Search Of EXCELence? "
It seems to me understanding when an installation s utilities run is important. Why is this? It s because utilities can make systems behave differently from how they usually do. And some of these behaviours can represent a challenge. It s often also valuable to reduce the utility window. What Is A Utility? There is no formal definition Continue reading "Utility Window Detection"
I ve tended to think Affinity Nodes aren t worthy of study because there s little you can do to influence them. However, that doesn t mean one shouldn t understand them. (In this post I m going to say processor when I mean logical processor and affnode when I mean affinity node . Also VL for Vertical High , VM for Continue reading "Engineering Part 9 Perhaps Affinity Nodes Are Interesting After…
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 memory Continue reading "Engineering Part 8 Remote Access Detection"
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 Facility Continue reading "Engineering Part 7 RMF Processor Home Address Fields"
Just a short post to add another AppleScript snippet some might find useful. (There will be performance-related posts along shortly; I have some in the works.) As you know from previous posts under the tag topics, I m automating as much of my Excel use as possible. So here s a short snippet of AppleScript to set Continue reading "Setting Axis Font Sizes In Excel With AppleScript"
In Excel Sorted With AppleScript I mentioned I might have a go at transposing rows and columns in an Excel spreadsheet with AppleScript. I said there were two things I could try each with a different use case: Transposing Rows And Columns In A Spreadsheet Transposing Rows And Columns In A Graph I Continue reading "Excel Two Types Of Transpose"
They say necessity is the mother of invention. But so, I d say, are impatience and frustration. I find the sorting dialog in Excel on Mac a source of both of these. So I wrote some AppleScript to remove some of the friction. I m sharing this because, yet again, I found nothing on the Web to Continue reading "Excel Sorted With AppleScript"
In Automating Microsoft Excel I wrote about some basic manipulation of graphs in Excel for Mac OS, using AppleScript. I m writing about it again because of the paucity of examples on the web. Here is an example that shows how to do a number of things in that vein. tell application 'Microsoft Excel' set c Continue reading "More AppleScript And Excel"
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, along Continue reading "Relating Parked Time To Cores"
Late last year I wrote a blog post: Drawers, Of Course. I ll admit I d half forgotten about it. Now that a few months have passed it s time to write about at least part of it again. So why write about it again now? I ve so much more experience with the instrumentation I described in that Continue reading "Drawers And More"
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 people Continue reading "Drawers, Of Course"
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 "
(This is not a post about plumbing.) 😀 It s been a while since I last wrote about personal automation. And in Stickiness I talked about what makes automations stick for me. This post is about experiments with RFID detection and automation. These actually turned into something I use daily when I m at home. Hobbyist Digital Continue reading "Reduced To A Single Tap"
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 bursty Continue reading "Bursty Batch Small Reprise"
This post is about Coupling Facility sizing particularly when you don t have one to start with. And particularly CPU. (Memory is reasonably catered for with CFSizer whether over the web or now in z/OSMF for z/OS 3.1.) And the reason I m writing about this is because I was recently asked to help size Continue reading "In My Estimation"
Bursty batch is quite common. For example, a customer I m dealing with right now kicks off a burst of batch at 7PM and another burst at 10PM. I doubt that customer is reading this blog post. Another customer has a burst of batch kicking off at 2AM. They probably will read this post. But their Continue reading "Bursty Batch"
I suppose I d better tell you what an E15 exit is else you might not read the rest of the post. 😀 DFSORT (and its competitor) allow you to send records to an exit routine. This happens as the very first thing for processing an individual record. This routine is called an E15 routine . Continue reading "Tips For Debugging A DFSORT E15 Exit"
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 a Continue reading "z16 ICA-SR Structure Service Times"
I hope you can tell that Marna and I had a lot of fun making this episode. I can t recall which of us came up with the cultural reference. But it sort of developed until the aftershow was sort of inevitable. Anyhow here are the show notes for Episode 33. The podcast series is Continue reading "Mainframe Performance Topics Podcast Episode 33 These Boots Were Made "
I m writing this on a flight to Munich, where I m presenting Parallel Sysplex Resiliency at a customer conference. By the way I wonder what happened to the word resilience and what the difference is between that and resiliency . But, it s a trip to a nice city and I expect to run into lots of friends Continue reading "Reporting For Duty?"
This post is about whether to run coupling facility (CF) LPARs using general purpose processors (GCPs). It might be in the category of “you can but do you think you should?” I’d like to tackle this from three angles: And the reason I’m writing about this now is the usual one: Recent customer experiences and Continue reading "CF LPARs In The GCP Pool?"
Three recent events led to this blog post: I was driving a while back and listening to podcasts. Two in particular by highly experienced podcasters who are very articulate. Meanwhile I d just completed editing a podcast episode of my own. (This was Episode 32, which you might have listened to already.) And a few weeks Continue reading "Like You Know?"
Episode 32 was, as always a slow train coming. I think it s a fun one as well as being informative. It was really good to have Scott back, and we recorded in the Poughkeepsie studio, just after SHARE Atlanta, March 2023. Talking of which, the aftershow relates to SHARE. It s a classic example of Continue reading "Mainframe Performance Topics Podcast Episode 32 Scott Free "
They say beauty is in the eye of the beholder. But I hope you ll agree this is a pretty interesting graph. It is, in fact, highly evolved but that evolution is a story for another time and place. I want to talk about what it s showing me in the hope your performance kitbag Continue reading "A Very Interesting Graph"
I was about to comment it’s been a while since I wrote about WLM but, in researching for this post, I discover it isn’t. The last post was WLM-Managed Initiators And zIIP. I seem to be telling a lot of customers their WLM service definition really needs some maintenance. In fact it’s every customer I’ve Continue reading "When Good Service Definitions Turn Bad"
I loftily talk about architecture a lot. What I m really getting at is gleaning an understanding of an installation s components hardware and software and some appreciation of what they re for, as well as how they behave. When I started doing Performance and Capacity many years ago I was less sensitive to Continue reading "Heading Back Into Db2- Architecture Part 1"
When I see an 8-byte field in a record I think of three possibilities, but I m prepared to discover the field in question is none of them. The three prime possibilities are: A character field A 64-bit counter A STCK value An interesting case occurs in SMF 74 Subtype 4: Two similar fields R744SVER Continue reading "Coupling Facility Structure Versions"
This is the first blog post I’ve written on my new work MacBook Pro. While it’s been a lot of work moving over it’s a better place as it’s an Apple Silicon M1 Max machine with lots of memory and disk space. That’s nice, but what’s the relevance to podcasting? Well, it’s very warm here Continue reading "Mainframe Performance Topics Podcast Episode 31 “Take It To The Macs”"
One item in the z/OS 2.5 announcement caught my eye. Now 2.5 is becoming more prevalent it s worth talking about it. It is zIIP and WLM-Managed Initiators. WLM-Managed Initiators The purpose of WLM-Managed Initiators is to balance system conditions against batch job initiation needs: Start too many initiators and you can cause CPU thrashing. Start Continue reading "WLM-Managed Initiators And zIIP"
I ve written several times about System Recovery Boost (SRB) so I ll try to make this one a quick one. For reference, previous posts were: Really Starting Something SRB And SMF Third Time’s The Charm For SRB – Or Is it? From that last one s title it clearly wasn t (the end of the matter). It s worth Continue reading "SRB And Shutdown"
For quite a while now I ve been able to do useful CPU analysis down at the individual logical processor level. In fact this post follows on from Engineering Part Five z14 IOPs at a discreet distance. I can t believe I haven t written about Defined Capacity Capping before but apparently I haven t. Continue reading "Engineering Part Six Defined Capacity Capping Considered Harmful?"
It s been a mighty long time since Marna and I got a podcast episode out and actually we started planning this episode long ago. It s finding good times to record that does it to us, as planning can be a bit more asynchronous. Hopefully this delay has enabled some of you to catch up Continue reading "Mainframe Performance Topics Podcast Episode 30 “Choices Choices”"
Passing reference to Blondes Have More Fun Or Do They?. Yeah, I know, it s a tortuous link. 🙂 And, nah, I never did own that album. 🙂 I first wrote about System Recovery Boost (SRB) and Recovery Process Boost (RPB) in SRB And SMF. Let me quote one passage from it: It should also Continue reading "Third Time s The Charm For SRB Or Is it?"
Question: What s brown and sticky? Answer: A stick. 🙂 It s not that kind of stickiness I m talking about. I ve experimented with lots of technologies over the years hardware, software, and services. Some of them have stuck and many of them haven t. I think it s worth exploring what makes some technologies stick(y) and some not Continue reading "Stickiness"