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All posts
A Note On Velocity
Not to be confused with Notational Velocity . A recent customer situation reminded me of how our code calculates velocity.
It’s worth sharing with you. The standard way of calculating velocity is to compute (Using Samples)/(Using Samples + Delay Samples) and convert to a percentage by multiplying by 100. [1] The numbers are all recorded in SMF Type 72 Subtype 3. We have two main graphs... [More]
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Twitter Polls: An Early View
It’s very early days for Twitter Polls but I think they have promise. So here’s a post on my experience with them in their infancy. [1] The point of writing about it is twofold: To encourage others to try it - both as a pollster and as a respondent [2] . To encourage Twitter to tweak it a bit. I’m always looking for ways to interact with people. As you probably know Twitter is... [More]
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A Parked Topic
In IRD And Hiperdispatch - Wrong ’Em Boyo I briefly mentioned the concepts of Parking and Unparking. It wasn’t appropriate to cover them in depth there. So I’ll talk about them now, focusing on the RMF instrumentation. But first a brief discussion on Parking versus IRD Logical Processor Management. IRD could - without Hiperdispatch - vary logical processors on and offline. [1]... [More]
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IRD And Hiperdispatch - Wrong 'Em Boyo
Applying the maxim “the customer is always right” this week revealed a bug in my analysis code.
It also gave me the opportunity to write about how RMF sees the interaction between IRD Weight Management and Hiperdispatch. [1] But let me start with some brief, basic information about the technologies in question.
If only this proves useful the blog post will still have been worthwhile.... [More]
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A Picture Of Dedication
Sometimes a little visual tweak can make all the difference.
This post is about one such case. Actually the code change to achieve it was quite complex but the visual rearrangement is simple. I have a number of customers with Integrated Coupling Facility (ICF) processor pools with both dedicated and shared Coupling Facility (CF) processors. For Production most people (sensibly) define their ICF... [More]
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Good Things Come in Threes?
It's that time of year when I start to think about writing conference presentations for user groups and conferences in 2016.
Already I have three in mind, with varying degrees of sketchiness.
Their working titles are: He Picks On CICS Fun With DDF So You Want To Be A Better Performance Specialist? I don't want to “design by committee ” and as for focus groups yeugh! But I... [More]
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Captivating Capture Ratios
I don’t think I’ve written about the concept of Capture Ratio [1] before.
To be honest it’s kind of a “nerdy” or “internal” thing.
But a recent experience suggests to me it is interesting, even if only for the wrong reason. What Is Capture Ratio? Not all CPU in a z/OS system can be attributed to a service class:
If you add up all the CPU in SMF... [More]
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Offline Processors Can't Hurt You
Or can they? Actually I can’t answer that question.
I’m aware my blog gets distributed in Development in Poughkeepsie (at very least) so maybe one of them can give a far better answer than I can. Though this post isn’t meant to address this in its entirety I have a point of view: A long time ago I learnt there were processor-related control blocks in 24-Bit Virtual. Though in... [More]
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And Latency Once More
This is about the third time I’ve written about this, and it probably won’t be the last. [1] I was presenting to customers about the Coupling Facility Path Latency statistics I’ve previously spoken of when one of them told me of the following incident.
I’m sure he won’t mind me sharing it without you, so long as I don’t identify the source. The customer has two... [More]
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The CPU That You Do
It’s difficult to write about a live situation for two reasons: You don’t want to spoil the surprise. You mustn’t expose the customer. Actually, make that three reasons: You don’t know how it’s actually going to turn out. So why am I writing at all? Well, the big engagement my team are involved in exemplifies the method for tuning CPU down, with a twist or two of its... [More]
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Slide Over A Bit More - Responsive Design
I’ve played some more since I wrote Slide Over A Bit , most notably from the perspective of developing a web app that acts as a Slide View widget. This post addresses some of the issues. In particular: Offline web apps, a feature of HTML 5. Responsive design - writing a web app that works well in Slide View mode while still looking OK in Full Screen mode. Remote hosting. I wrote a better... [More]
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Slide Over A Bit
The last post hit both the “Mainframe” and “Performance” aspects of this blog.
This one is firmly in the “Topics” category. [1] You might’ve noticed a slew of announcements from Apple recently, and iOS 9 and OS X 10.11 “El Capitan” delivery. [2] I’d like to talk here about one feature of iOS 9 that is more useful than it appears at first... [More]
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CICS and Batch DB2 Identifiers
DB2 Accounting Trace names are a(n endless) [1] source of fascination to me. As many of you know, bridging the gap between DB2 and callers and the environment is permanently an imperative for me. These names might be cryptic but they can usually be related to non-DB2 concepts. As I’m about to explain this to colleagues at work I thought I might as well explain it to the world (or at least my... [More]
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What's The Latency Really?
In What’s The Latency, Kenneth? I talked about Coupling Facility Link distance and OA37826.
The whole supposition was that you might want to know about really long links. A recent situation showed me that short distances might be a different and interesting matter. So what’s a microsecond or two amongst friends? Well, 1μs represents 100m of distance and 2μs represents 200m.
This is,... [More]
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The Right Curves?
In true IBM fashion this post features graphs without scales. [1] My aim is to share a rhetorical device I used in a recent customer workshop.
I hope you find it useful. [2] The customer was worried about a piece of hardware whose responsiveness had deteriorated over the past year, but got better in recent days, coinciding with some tuning changes they’d made.
This graph shows that:... [More]
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