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Dr. Neil Gunther

@drqz.bsky.social

54 followers 26 following 110 posts

Performance analyst, 'rocket scientist' & Xerox PARC alum 🇦🇺🇺🇸 Consultant, author, teacher, physics, math, stats, chem and some 🎸 performance too.

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Dr. Neil Gunther @drqz.bsky.social · Nov 15

Performance issues are always lurking. Better to prepare for them and otherwise prevent them in the future.
Guerrilla Capacity & Performance online classes offer some of the most powerful techniques applied across all platforms. perfdynamics.com/Classes/sche...

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Dr. Neil Gunther @drqz.bsky.social · 2d

I'll forgive the fact that the Bohr atomic model only works for a single orbital electron. (Details)

Dr. Neil Gunther @drqz.bsky.social · 2d

Apart from the fact that this GenAI can't spell ... AFAIK, Bohr never wore a bowtie (but Thomas Edison did) and Schrödinger never sported a mustache (but Max Planck did). 🥸

Dr. Neil Gunther @drqz.bsky.social · 2d

Ordinary AI output requires extraordinary human verification. (Apologies to C. Sagan)

Dr. Neil Gunther @drqz.bsky.social · 3d

Dr. Neil Gunther @drqz.bsky.social · 5d

DR still in progress for AMZN.com itself ... 🧐

Dr. Neil Gunther @drqz.bsky.social · 13d

Productivity: If you want to be more productive, go to sleep.
www.perfdynamics.com/Manifesto/gc...

Dr. Neil Gunther @drqz.bsky.social · 20d

Some performance consequences often overlooked in redundancy plans
perfdynamics.blogspot.com/2014/03/perf...

Performance of N+1 Redundancy

How can you determine the performance impact on SLAs after an N+1 redundant hosting configuration fails over ? This question came up in the...

perfdynamics.blogspot.com

Dr. Neil Gunther @drqz.bsky.social · Sep 18

Out of The Queue Comes ... Amdahl’s Law!
www.perfdynamics.com/Papers/amdsy...

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Dr. Neil Gunther @drqz.bsky.social · Aug 8

RIP James Lovell, commander of Apollo 13 (played by Tom Hanks in the movie of the same name), has died at age 97.

Dr. Neil Gunther @drqz.bsky.social · Aug 7

B. All measurements (data) are wrong ... by definition.
The only question is, can you tolerate the wrongness?
If you're not informed how wrong data is, how can you decide?

Dr. Neil Gunther @drqz.bsky.social · Aug 7

A. Displaying metrics, errors, etc., is not the same thing as displaying metric errors.
1. How it is (old school top)
CPU usage: 5.79 %usr, 4.51 %sys, 89.68 %idl
2. How it could be (nay, SHOULD be)
CPU usage: 5.79 ± 0.29 %usr, 4.51 ± 0.23 %sys, 89.68 ± 4.48 %idl

Dr. Neil Gunther @drqz.bsky.social · Aug 6

Online classroom buzz www.perfdynamics.com/Classes/comm...
What Guerrilla Grads are saying about why you should become an alumnus.
Enroll here www.perfdynamics.com/Classes/sche... 🎓

#performance #engineering #capacity #management #marketplace #trends #GCAP #GDAT #PDQW

Dr. Neil Gunther @drqz.bsky.social · Aug 5

BTW: the Editor-in-Chief is looking for assistant editors and reviewers. Email him at <[email protected]>

Dr. Neil Gunther @drqz.bsky.social · Aug 5

PSA: New open access Journal of Systems Scalability launching.
Editor-in-Chief: Carlos Juiz
www.icck.org/jss
#systems #architecture #performance #scalability

Dr. Neil Gunther @drqz.bsky.social · Aug 1

GCAP Day 10. What you missed:
❥ Avalanche vs. Paxos coordination scalability
❥ Memcache scalability analysis with USL
❥ Queueing models of Kubernetes control and data planes
❥ Class dismissed 📚 🎓🍻

Dr. Neil Gunther @drqz.bsky.social · Jul 31

Never let reality get in the way of a good performance model.

Dr. Neil Gunther @drqz.bsky.social · Jul 31

GCAP Day 9. What you missed:
❥ Rate limiting services via Guerrilla queueing models
❥ Performance visualization tools
❥ Zookeeper scalability analysis with the USL
www.perfdynamics.com/Manifesto/US...

Dr. Neil Gunther @drqz.bsky.social · Jul 30

GCAP Day 8. What you missed:
❥ Linear vs Dynamic programming
❥ Benchmarking/load testing prats and pitfalls
❥ Prelim discussion about Kefka, Kubernetes
❥ What kind of scheduler is in the K8s control plane?

Dr. Neil Gunther @drqz.bsky.social · Jul 29

GCAP Day 7. What you missed:
❥ Python least_squares() seems to be a bloated implementation of codes in the "Numerical Recipes" book.
❥ To apply the USL, use curve_fit() instead.
❥ Multivariate regression: How to reattach (noisy) fingers to amputated daily "numero uno" data

Dr. Neil Gunther @drqz.bsky.social · Jul 28

GCAP Day 6. What you missed:
❥ USL scalability analysis
lnkd.in/gxaaAiww
❥ Student gets PDQ 7.0 running on Python 3.12 👏🎉
lnkd.in/gPzzHiez
❥ Homework Q-5 solved (a) analytically (b) cf. with corresponding PyDQ model
- Discussed why analytic calculation was wrong

Dr. Neil Gunther @drqz.bsky.social · Jul 27

Ditto for the performance analysis & capacity planning of computer systems in general:
- Assume failure
- Plan for resilience
- Monitor everything
- Analyze and predict performance and capacity
- Have an exceptional performance team of skilled experts

lnkd.in/g8eGRnYq

Dr. Neil Gunther @drqz.bsky.social · Jul 25

RIP Chuck Mangione
www.youtube.com/watch?v=c4el...

Chuck Mangione - Feels So Good (The Old Grey Whistle Test, January 16th, 1979)

YouTube video by Chuck Mangione

www.youtube.com

Reposted by Dr. Neil Gunther

Dr. Neil Gunther @drqz.bsky.social · Jun 24

Guerrilla Capacity Planning (GCAP) Online
— EU Edition — registration is now OPEN
Dates: July 21 through August 1, 2025
Times: 1500 - 1900 CET
www.perfdynamics.com/Classes/sche...

Click on the DETAILS box (at the RHS) to register
www.eventbrite.com/e/guerrilla-...

Dr. Neil Gunther @drqz.bsky.social · Jul 3

#TIL Product Solutions Physicist 😳

Dr. Neil Gunther @drqz.bsky.social · Jul 1

I recently discovered the original 1992 paper where I first introduced the concept of barycentric coordinates for visualizing multiprocessor/multicore performance. www.perfdynamics.com/papers.pdf

More modern renditions (animations) can be viewed here www.perfdynamics.com/Tools/tools....